WorldWideScience

Sample records for scanning probe tools

  1. Scanning Probe Optical Tweezers: a new tool to study DNA-protein interactions

    NARCIS (Netherlands)

    Huisstede, J.H.G.

    2006-01-01

    The main goal of the work described in this thesis is to construct a microscope in which OT and scanning probe microscopy (SPM) are combined, to be able to localize proteins while simultaneously controlling the tension within the DNA molecule. This apparatus enables the study of the effect of

  2. Magnetic hydroxyapatite coatings as a new tool in medicine: A scanning probe investigation

    Energy Technology Data Exchange (ETDEWEB)

    Gambardella, A., E-mail: a.gambardella@biomec.ior.it [Laboratorio di NanoBiotecnologie (NaBi), Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, I-40136 Bologna (Italy); Bianchi, M. [Laboratorio di NanoBiotecnologie (NaBi), Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, I-40136 Bologna (Italy); Kaciulis, S.; Mezzi, A.; Brucale, M. [Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Consiglio Nazionale delle Ricerche, Via Salaria km 29.300, P.O. Box 10, 00015 Monterotondo Staz, Roma (Italy); Cavallini, M. [Magnetic Nanostructures for Spintronics and Nanomedicine, CNR-ISMN, Via Gobetti 101, 40129 Bologna (Italy); Herrmannsdoerfer, T.; Chanda, G.; Uhlarz, M. [Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden (Germany); Cellini, A.; Pedna, M.F. [Unità Operativa Microbiologia Laboratorio Unico del Centro Servizi AUSL della Romagna, Pievesestina, Cesena (Italy); Sambri, V. [Unità Operativa Microbiologia Laboratorio Unico del Centro Servizi AUSL della Romagna, Pievesestina, Cesena (Italy); Dipartimento di Medicina Specialistica, Diagnostica e Sperimentale (DIMES), Università degli Studi di Bologna, Via Zamboni 33, 40126 Bologna (Italy); Marcacci, M.; Russo, A. [Laboratorio di NanoBiotecnologie (NaBi), Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, I-40136 Bologna (Italy); Laboratorio di Biomeccanica ed Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Via di Barbiano1/10, I-40136 Bologna (Italy)

    2016-05-01

    Hydroxyapatite films enriched with magnetite have been fabricated via a Pulsed Plasma Deposition (PPD) system with the final aim of representing a new platform able to disincentivate bacterial adhesion and biofilm formation. The chemical composition and magnetic properties of films were respectively examined by X-ray photoelectron spectroscopy (XPS) and Superconducting Quantum Interference Device (SQUID) measurements. The morphology and conductive properties of the magnetic films were investigated via a combination of scanning probe technologies including atomic force microscopy (AFM), electrostatic force microscopy (EFM), and scanning tunneling microscopy (STM). Interestingly, the range of adopted techniques allowed determining the preservation of the chemical composition and magnetic properties of the deposition target material while STM analysis provided new insights on the presence of surface inhomogeneities, revealing the presence of magnetite-rich islands over length scales compatible with the applications. Finally, preliminary results of bacterial adhesion tests, indicated a higher ability of magnetic hydroxyapatite films to reduce Escherichia coli adhesion at 4 h from seeding compared to control hydroxyapatite films. - Highlights: • Pulsed Plasma Deposition technique is used to deposit magnetite-rich films of hydroxyapatite for antibacterial purposes. • The preservation of the chemical composition and magnetic properties of the deposition target material is demonstrated. • Scanning tunnelling microscopy is employed for the first time to reveal the presence of magnetite-rich states at the surface. • Preliminary tests suggest that Mag HA films hamper the adhesion of Escherichia coli compared to not magnetic films.

  3. Scanning probe microscopy

    International Nuclear Information System (INIS)

    Mainsbridge, B.

    1994-01-01

    In late 1959, Richard Feynman observed that manoeuvring atoms was something that could be done in principle but has not been done, 'because we are too big'. In 1982, the scanning tunnelling microscope (STM) was invented and is now a central tool for the construction of nanoscale devices in what was known as molecular engineering, and now, nanotechnology. The principles of the microscope are outlined and references are made to other scanning devices which have evolved from the original invention. The method of employment of the STM as a machine tool is described and references are made to current speculations on applications of the instrument in nanotechnology. A short bibliography on this topic is included. 27 refs., 7 figs

  4. Scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mainsbridge, B [Murdoch Univ., WA (Australia). School of Mathematical and Physical Sciences

    1994-12-31

    In late 1959, Richard Feynman observed that manoeuvring atoms was something that could be done in principle but has not been done, `because we are too big`. In 1982, the scanning tunnelling microscope (STM) was invented and is now a central tool for the construction of nanoscale devices in what was known as molecular engineering, and now, nanotechnology. The principles of the microscope are outlined and references are made to other scanning devices which have evolved from the original invention. The method of employment of the STM as a machine tool is described and references are made to current speculations on applications of the instrument in nanotechnology. A short bibliography on this topic is included. 27 refs., 7 figs.

  5. Nanobits: customizable scanning probe tips

    DEFF Research Database (Denmark)

    Kumar, Rajendra; Shaik, Hassan Uddin; Sardan Sukas, Özlem

    2009-01-01

    We present here a proof-of-principle study of scanning probe tips defined by planar nanolithography and integrated with AFM probes using nanomanipulation. The so-called 'nanobits' are 2-4 mu m long and 120-150 nm thin flakes of Si3N4 or SiO2, fabricated by electron beam lithography and standard s...

  6. Scanning vector Hall probe microscopy

    International Nuclear Information System (INIS)

    Cambel, V.; Gregusova, D.; Fedor, J.; Kudela, R.; Bending, S.J.

    2004-01-01

    We have developed a scanning vector Hall probe microscope for mapping magnetic field vector over magnetic samples. The microscope is based on a micromachined Hall sensor and the cryostat with scanning system. The vector Hall sensor active area is ∼5x5 μm 2 . It is realized by patterning three Hall probes on the tilted faces of GaAs pyramids. Data from these 'tilted' Hall probes are used to reconstruct the full magnetic field vector. The scanning area of the microscope is 5x5 mm 2 , space resolution 2.5 μm, field resolution ∼1 μT Hz -1/2 at temperatures 10-300 K

  7. Scanning probe microscopy competency development

    Energy Technology Data Exchange (ETDEWEB)

    Hawley, M.E.; Reagor, D.W.; Jia, Quan Xi [and others

    1998-12-31

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The project collaborators developed an ultra-high vacuum scanning tunneling microscope (UHV-STM) capability, integrated it with existing scanning probe microscopes, and developed new, advanced air-based scanning force techniques (SPMs). Programmatic, basic, and industrially related laboratory research requires the existence of SPMs, as well as expertise capable of providing local nano-scale information. The UHV-STM capability, equipped with load-lock system and several surface science techniques, will allow introduction, examination, and reaction of surfaces prepared under well-controlled vacuum conditions, including the examination of morphology and local bonding associated with the initial stages of film growth under controlled growth conditions. The resulting capabilities will enable the authors to respond to a variety of problems requiring local characterization of conducting and nonconducting surfaces in liquids, air, and UHV.

  8. Large Scale Scanning Probe Microscope "Making Shear Force Scanning visible."

    NARCIS (Netherlands)

    Bosma, E.; Offerhaus, Herman L.; van der Veen, Jan T.; van der Veen, J.T.; Segerink, Franciscus B.; Wessel, I.M.

    2010-01-01

    We describe a demonstration of a scanning probe microscope with shear-force tuning fork feedback. The tuning fork is several centimeters long, and the rigid fiber is replaced by a toothpick. By scaling this demonstration to visible dimensions the accessibility of shear-force scanning and tuning fork

  9. Scanning probe lithography for nanoimprinting mould fabrication

    International Nuclear Information System (INIS)

    Luo Gang; Xie Guoyong; Zhang Yongyi; Zhang Guoming; Zhang Yingying; Carlberg, Patrick; Zhu Tao; Liu Zhongfan

    2006-01-01

    We propose a rational fabrication method for nanoimprinting moulds by scanning probe lithography. By wet chemical etching, different kinds of moulds are realized on Si(110) and Si(100) surfaces according to the Si crystalline orientation. The structures have line widths of about 200 nm with a high aspect ratio. By reactive ion etching, moulds with patterns free from the limitation of Si crystalline orientation are also obtained. With closed-loop scan control of a scanning probe microscope, the length of patterned lines is more than 100 μm by integrating several steps of patterning. The fabrication process is optimized in order to produce a mould pattern with a line width about 10 nm. The structures on the mould are further duplicated into PMMA resists through the nanoimprinting process. The method of combining scanning probe lithography with wet chemical etching or reactive ion etching (RIE) provides a resistless route for the fabrication of nanoimprinting moulds

  10. Developments in Scanning Hall Probe Microscopy

    Science.gov (United States)

    Chouinard, Taras; Chu, Ricky; David, Nigel; Broun, David

    2009-05-01

    Low temperature scanning Hall probe microscopy is a sensitive means of imaging magnetic structures with high spatial resolution and magnetic flux sensitivity approaching that of a Superconducting Quantum Interference Device. We have developed a scanning Hall probe microscope with novel features, including highly reliable coarse positioning, in situ optimization of sensor-sample alignment and capacitive transducers for linear, long range positioning measurement. This has been motivated by the need to reposition accurately above fabricated nanostructures such as small superconducting rings. Details of the design and performance will be presented as well as recent progress towards time-resolved measurements with sub nanosecond resolution.

  11. An interchangeable scanning Hall probe/scanning SQUID microscope

    International Nuclear Information System (INIS)

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin; Chen, Tse-Jun; Wang, M. J.; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung

    2014-01-01

    We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10 −7 T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La 2/3 Ca 1/3 MnO 3 thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K

  12. An interchangeable scanning Hall probe/scanning SQUID microscope

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Tse-Jun; Wang, M. J. [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei City 25137, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2014-08-15

    We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10{sup −7} T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.

  13. Scanning probe microscopy experiments in microgravity

    International Nuclear Information System (INIS)

    Drobek, Tanja; Reiter, Michael; Heckl, Wolfgang M.

    2004-01-01

    The scanning probe microscopy setups are small, lightweight and do not require vacuum or high voltage supply. In addition, samples can be investigated directly without further preparation. Therefore, these techniques are well-suited for applications in space, in particular, for operation on the International Space Station (ISS) or for high resolution microscopy on planetary missions. A feasibility study for a scanning tunneling microscopy setup was carried out on a parabolic flight campaign in November 2001 in order to test the technical setup for microgravity applications. With a pocket-size design microscope, a graphite surface was imaged under ambient conditions. Atomic resolution was achieved although the quality of the images was inferior in comparison to laboratory conditions. Improvements for future scanning probe microscopy experiments in microgravity are suggested

  14. Aligned ion implementation using scanning probes

    Energy Technology Data Exchange (ETDEWEB)

    Persaud, A

    2006-12-12

    A new technique for precision ion implantation has been developed. A scanning probe has been equipped with a small aperture and incorporated into an ion beamline, so that ions can be implanted through the aperture into a sample. By using a scanning probe the target can be imaged in a non-destructive way prior to implantation and the probe together with the aperture can be placed at the desired location with nanometer precision. In this work first results of a scanning probe integrated into an ion beamline are presented. A placement resolution of about 120 nm is reported. The final placement accuracy is determined by the size of the aperture hole and by the straggle of the implanted ion inside the target material. The limits of this technology are expected to be set by the latter, which is of the order of 10 nm for low energy ions. This research has been carried out in the context of a larger program concerned with the development of quantum computer test structures. For that the placement accuracy needs to be increased and a detector for single ion detection has to be integrated into the setup. Both issues are discussed in this thesis. To achieve single ion detection highly charged ions are used for the implantation, as in addition to their kinetic energy they also deposit their potential energy in the target material, therefore making detection easier. A special ion source for producing these highly charged ions was used and their creation and interactions with solids of are discussed in detail. (orig.)

  15. Aligned ion implantation using scanning probes

    International Nuclear Information System (INIS)

    Persaud, A.

    2006-01-01

    A new technique for precision ion implantation has been developed. A scanning probe has been equipped with a small aperture and incorporated into an ion beamline, so that ions can be implanted through the aperture into a sample. By using a scanning probe the target can be imaged in a non-destructive way prior to implantation and the probe together with the aperture can be placed at the desired location with nanometer precision. In this work first results of a scanning probe integrated into an ion beamline are presented. A placement resolution of about 120 nm is reported. The final placement accuracy is determined by the size of the aperture hole and by the straggle of the implanted ion inside the target material. The limits of this technology are expected to be set by the latter, which is of the order of 10 nm for low energy ions. This research has been carried out in the context of a larger program concerned with the development of quantum computer test structures. For that the placement accuracy needs to be increased and a detector for single ion detection has to be integrated into the setup. Both issues are discussed in this thesis. To achieve single ion detection highly charged ions are used for the implantation, as in addition to their kinetic energy they also deposit their potential energy in the target material, therefore making detection easier. A special ion source for producing these highly charged ions was used and their creation and interactions with solids of are discussed in detail. (orig.)

  16. Full information acquisition in scanning probe microscopy and spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jesse, Stephen; Belianinov, Alex; Kalinin, Sergei V.; Somnath, Suhas

    2017-04-04

    Apparatus and methods are described for scanning probe microscopy and spectroscopy based on acquisition of full probe response. The full probe response contains valuable information about the probe-sample interaction that is lost in traditional scanning probe microscopy and spectroscopy methods. The full probe response is analyzed post data acquisition using fast Fourier transform and adaptive filtering, as well as multivariate analysis. The full response data is further compressed to retain only statistically significant components before being permanently stored.

  17. Scanning probe recognition microscopy investigation of tissue scaffold properties

    Science.gov (United States)

    Fan, Yuan; Chen, Qian; Ayres, Virginia M; Baczewski, Andrew D; Udpa, Lalita; Kumar, Shiva

    2007-01-01

    Scanning probe recognition microscopy is a new scanning probe microscopy technique which enables selective scanning along individual nanofibers within a tissue scaffold. Statistically significant data for multiple properties can be collected by repetitively fine-scanning an identical region of interest. The results of a scanning probe recognition microscopy investigation of the surface roughness and elasticity of a series of tissue scaffolds are presented. Deconvolution and statistical methods were developed and used for data accuracy along curved nanofiber surfaces. Nanofiber features were also independently analyzed using transmission electron microscopy, with results that supported the scanning probe recognition microscopy-based analysis. PMID:18203431

  18. Metrological large range scanning probe microscope

    International Nuclear Information System (INIS)

    Dai Gaoliang; Pohlenz, Frank; Danzebrink, Hans-Ulrich; Xu Min; Hasche, Klaus; Wilkening, Guenter

    2004-01-01

    We describe a metrological large range scanning probe microscope (LR-SPM) with an Abbe error free design and direct interferometric position measurement capability, aimed at versatile traceable topographic measurements that require nanometer accuracy. A dual-stage positioning system was designed to achieve both a large measurement range and a high measurement speed. This dual-stage system consists of a commercially available stage, referred to as nanomeasuring machine (NMM), with a motion range of 25 mmx25 mmx5 mm along x, y, and z axes, and a compact z-axis piezoelectric positioning stage (compact z stage) with an extension range of 2 μm. The metrological LR-SPM described here senses the surface using a stationary fixed scanning force microscope (SFM) head working in contact mode. During operation, lateral scanning of the sample is performed solely by the NMM. Whereas the z motion, controlled by the SFM signal, is carried out by a combination of the NMM and the compact z stage. In this case the compact z stage, with its high mechanical resonance frequency (greater than 20 kHz), is responsible for the rapid motion while the NMM simultaneously makes slower movements over a larger motion range. To reduce the Abbe offset to a minimum the SFM tip is located at the intersection of three interferometer measurement beams orientated in x, y, and z directions. To improve real time performance two high-end digital signal processing (DSP) systems are used for NMM positioning and SFM servocontrol. Comprehensive DSP firmware and Windows XP-based software are implemented, providing a flexible and user-friendly interface. The instrument is able to perform large area imaging or profile scanning directly without stitching small scanned images. Several measurements on different samples such as flatness standards, nanostep height standards, roughness standards as well as sharp nanoedge samples and 1D gratings demonstrate the outstanding metrological capabilities of the instrument

  19. Tools to probe the universe

    International Nuclear Information System (INIS)

    Lagage, P.O.; Augueres, J.L.; Amiaux, J.; Cara, Ch.; Fontignie, J.; Rio, Y.; Fermon, C.; Pannetier-Lecoeur, M.; De Vismes, A.; Cordier, B.; Fesquet, M.; Ferrando, Ph.; Authier, M.; Pantin, E.; Glicenstein, J.F.; Boulade, O.; Refregier, A.; Stolarczyk, Th.; Agnese, P.; Rodriguez, L.; Agnese, P.; Pigot, C.; Duband, L.; Limousin, O.; Delagnes, E.; Turck-Chieze, S.; Carton, P.H.; Starck, J.L.; Bournaud, F.; Teyssier, R.; Audit, E.; Brun, A.S.; Leca, P.; Menache, Ch.; Pomarede, D.; Thooris, B.; Meis, C.

    2009-01-01

    This special issue of Clefs CEA journal is entirely devoted to astrophysics and to the exploration and probing of the Universe. The second part of this dossier, described here, makes a status of the tools used to probe the universe: telescopes, imaging spectrometers, data processing and simulation. Content: A - Telescopes of the future: 1. Seeing further out: JWST: looking back on a past 13 billion years old, Space specifics: the learning curve to know-how, Fabricating a corona-graph mask, SVOM, a satellite to detect the explosions of the first stars to be formed in the Universe; 2. Seeing more precisely: SIMBOL-X, pioneering formation flying, ELT/METIS, a 42-meter giant, One hundred telescopes for the CTA arrays; 3. Seeing wider: Euclid, mapping the extragalactic sky, ANTARES: the neutrino, another cosmic messenger; B - The new generation of imaging spectrometers: Observing the Universe in the submillimeter spectral region, The X-ray Universe, Space cryo-coolers, Out in the extreme, tumultuous Universe, Probing the Sun with GOLF-NG, Focus: From light to imagery; C - Data analysis in astrophysics; D - Numerical simulation in astrophysics: Information technology and theoretical predictions in astrophysics, Supercomputers for a better understanding of the Universe, The visualization of astrophysical simulations, Godunov, a numerical platform for education and research

  20. Confocal scanning microscopy with multiple optical probes for high speed measurements and better imaging

    Science.gov (United States)

    Chun, Wanhee; Lee, SeungWoo; Gweon, Dae-Gab

    2008-02-01

    Confocal scanning microscopy (CSM) needs a scanning mechanism because only one point information of specimen can be obtained. Therefore the speed of the confocal scanning microscopy is limited by the speed of the scanning tool. To overcome this limitation from scanning tool we propose another scanning mechanism. We make three optical probes in the specimen under confocal condition of each point. Three optical probes are moved by beam scanning mechanism with shared resonant scanning mirror (RM) and galvanometer driven mirror (GM). As each optical probe scan allocated region of the specimen, information from three points is obtained simultaneously and image acquisition time is reduced. Therefore confocal scanning microscopy with multiple optical probes is expected to have three times faster speed of the image acquisition than conventional one. And as another use, multiple optical probes to which different light wavelength is applied can scan whole same region respectively. It helps to obtain better contrast image in case of specimens having different optical characteristics for specific light wavelength. In conclusion confocal scanning microscopy with multiple optical probes is useful technique for views of image acquisition speed and image quality.

  1. Scanning probe methods applied to molecular electronics

    Energy Technology Data Exchange (ETDEWEB)

    Pavlicek, Niko

    2013-08-01

    Scanning probe methods on insulating films offer a rich toolbox to study electronic, structural and spin properties of individual molecules. This work discusses three issues in the field of molecular and organic electronics. An STM head to be operated in high magnetic fields has been designed and built up. The STM head is very compact and rigid relying on a robust coarse approach mechanism. This will facilitate investigations of the spin properties of individual molecules in the future. Combined STM/AFM studies revealed a reversible molecular switch based on two stable configurations of DBTH molecules on ultrathin NaCl films. AFM experiments visualize the molecular structure in both states. Our experiments allowed to unambiguously determine the pathway of the switch. Finally, tunneling into and out of the frontier molecular orbitals of pentacene molecules has been investigated on different insulating films. These experiments show that the local symmetry of initial and final electron wave function are decisive for the ratio between elastic and vibration-assisted tunneling. The results can be generalized to electron transport in organic materials.

  2. The Scanning Theremin Microscope: A Model Scanning Probe Instrument for Hands-On Activities

    Science.gov (United States)

    Quardokus, Rebecca C.; Wasio, Natalie A.; Kandel, S. Alex

    2014-01-01

    A model scanning probe microscope, designed using similar principles of operation to research instruments, is described. Proximity sensing is done using a capacitance probe, and a mechanical linkage is used to scan this probe across surfaces. The signal is transduced as an audio tone using a heterodyne detection circuit analogous to that used in…

  3. Improved controlled atmosphere high temperature scanning probe microscope

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Wu, Yuehua; Jacobsen, Torben

    2013-01-01

    fuel cells and electrolyzer cells. Here, we report on advanced improvements of our original controlled atmosphere high temperature scanning probe microscope, CAHT-SPM. The new microscope can employ a broad range of the scanning probe techniques including tapping mode, scanning tunneling microscopy......, scanning tunneling spectroscopy, conductive atomic force microscopy, and Kelvin probe force microscopy. The temperature of the sample can be as high as 850 °C. Both reducing and oxidizing gases such as oxygen, hydrogen, and nitrogen can be added in the sample chamber and the oxygen partial pressure (pO2...

  4. Scanning microscopic four-point conductivity probes

    DEFF Research Database (Denmark)

    Petersen, Christian Leth; Hansen, Torben Mikael; Bøggild, Peter

    2002-01-01

    A method for fabricating microscopic four-point probes is presented. The method uses silicon-based microfabrication technology involving only two patterning steps. The last step in the fabrication process is an unmasked deposition of the conducting probe material, and it is thus possible to select...... the conducting material either for a silicon wafer or a single probe unit. Using shadow masking photolithography an electrode spacing (pitch) down to 1.1 mum was obtained, with cantilever separation down to 200 run. Characterisation measurements have shown the microscopic probes to be mechanically very flexible...

  5. Scanning probe microscope simulator for the assessment of noise in scanning probe microscopy controllers

    International Nuclear Information System (INIS)

    Wutscher, T.; Niebauer, J.; Giessibl, F. J.

    2013-01-01

    We present an electronic circuit that allows to calibrate and troubleshoot scanning probe microscopy (SPM) controllers with respect to their noise performance. The control signal in an SPM is typically highly nonlinear—the tunneling current in scanning tunneling microscopy (STM) varies exponentially with distance. The exponential current-versus-voltage characteristics of diodes allow to model the current dependence in STM. Additional inputs allow to simulate the effects of external perturbations and the reactions of the control electronics. We characterized the noise performance of the feedback controller using the apparent topography roughness of recorded images. For a comparison of different STM controllers, an optimal gain parameter was determined by exploring settling times through a rectangular perturbation signal. We used the circuit to directly compare the performance of two types of SPM controllers used in our laboratory

  6. Fabrication of all diamond scanning probes for nanoscale magnetometry

    OpenAIRE

    Appel Patrick; Neu Elke; Ganzhorn Marc; Barfuss Arne; Batzer Marietta; Gratz Micha; Tschoepe Andreas; Maletinsky Patrick

    2016-01-01

    The electronic spin of the nitrogen vacancy (NV) center in diamond forms an atomically sized, highly sensitive sensor for magnetic fields. To harness the full potential of individual NV centers for sensing with high sensitivity and nanoscale spatial resolution, NV centers have to be incorporated into scanning probe structures enabling controlled scanning in close proximity to the sample surface. Here, we present an optimized procedure to fabricate single-crystal, all-diamond scanning probes s...

  7. Monolithically Integrated, Mechanically Resilient Carbon-Based Probes for Scanning Probe Microscopy

    Science.gov (United States)

    Kaul, Anupama B.; Megerian, Krikor G.; Jennings, Andrew T.; Greer, Julia R.

    2010-01-01

    Scanning probe microscopy (SPM) is an important tool for performing measurements at the nanoscale in imaging bacteria or proteins in biology, as well as in the electronics industry. An essential element of SPM is a sharp, stable tip that possesses a small radius of curvature to enhance spatial resolution. Existing techniques for forming such tips are not ideal. High-aspect-ratio, monolithically integrated, as-grown carbon nanofibers (CNFs) have been formed that show promise for SPM applications by overcoming the limitations present in wet chemical and separate substrate etching processes.

  8. Nanobits - exchangable and customisable scanning probe tips

    DEFF Research Database (Denmark)

    Yildiz, Izzet

    dimensions: tips suitable for imaging high-aspect ratio structures and sidewall profiles were designed. Tip diameters in the order of 30 nm were reproducibly obtained with the FIB milling and the smallest tip diameter achieved was ... process by providing direct picking up of the NanoBits by the AFM probe was investigated. Two different bending mechanisms were studied for out-of-plane bending studies: FIB irradiation- and the residual stress-driven bending in bimorph structures. With FIB irradiation studies, NanoBits were demonstrated...... of the structure which may be starting at 170°C. The fabricated NanoBits were assembled and their performance as AFM probes were tested at OFFIS. The NanoBits were successfully picked up by a microgripper, collected in a cartridge and mounted to an AFM probe. Performances of the assembled high-aspect-ratio Nano...

  9. Nanopatterning reconfigurable magnetic landscapes via thermally assisted scanning probe lithography

    Science.gov (United States)

    Albisetti, E.; Petti, D.; Pancaldi, M.; Madami, M.; Tacchi, S.; Curtis, J.; King, W. P.; Papp, A.; Csaba, G.; Porod, W.; Vavassori, P.; Riedo, E.; Bertacco, R.

    2016-06-01

    The search for novel tools to control magnetism at the nanoscale is crucial for the development of new paradigms in optics, electronics and spintronics. So far, the fabrication of magnetic nanostructures has been achieved mainly through irreversible structural or chemical modifications. Here, we propose a new concept for creating reconfigurable magnetic nanopatterns by crafting, at the nanoscale, the magnetic anisotropy landscape of a ferromagnetic layer exchange-coupled to an antiferromagnetic layer. By performing localized field cooling with the hot tip of a scanning probe microscope, magnetic structures, with arbitrarily oriented magnetization and tunable unidirectional anisotropy, are reversibly patterned without modifying the film chemistry and topography. This opens unforeseen possibilities for the development of novel metamaterials with finely tuned magnetic properties, such as reconfigurable magneto-plasmonic and magnonic crystals. In this context, we experimentally demonstrate spatially controlled spin wave excitation and propagation in magnetic structures patterned with the proposed method.

  10. Scanning Probe Microscopy at 650 °C in Air

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Jacobsen, Torben; Nørgaard, Anne-Mette

    2009-01-01

    The controlled atmosphere high temperature scanning probe microscope was designed to study the electrical properties of surfaces at elevated temperatures by using the probe as an electrode. The capability of a simultaneous acquisition of topographical and electrical data for the same surface area...

  11. Characterization of coating probe with Ti-DLC for electrical scanning probe microscope

    International Nuclear Information System (INIS)

    Shia Xiaolei; Guo Liqiu; Bai Yang; Qiao Lijie

    2011-01-01

    In electrical scanning probe microscope (ESPM) applications, the wear and conductivity of the probe are undoubtedly serious concerns since they affect the integrity of the measurements. This study investigates the characterization of Ti doped diamond-like-carbon (DLC) as coating material on a silicon cantilever for ESPM. We deposited a layer of Ti-DLC thin film on the surface of Si cantilever by magnetron sputtering. The morphology and composition of the Ti-DLC films were characterized by scanning electron microscopy and Raman spectroscopy, respectively. We also compared the wear resistance, electric conductivity and scanning image quality of the Ti-DLC-coated probes with those of commercially available conductive probes. The results showed that the electric conductivity and the scanning image quality of the Ti-DLC-coated probes were the same as the commercial conductive probes, while the wear resistance and service life was significantly better.

  12. Optical characterication of probes for photon scanning tunnelling microscopy

    DEFF Research Database (Denmark)

    Vohnsen, Brian; Bozhevolnyi, Sergey I.

    1999-01-01

    The photon scanning tunnelling microscope is a well-established member of the family of scanning near-field optical microscopes used for optical imaging at the sub-wavelength scale. The quality of the probes, typically pointed uncoated optical fibres, used is however difficult to evaluate...

  13. Scanning probe microscopy in material science and biology

    International Nuclear Information System (INIS)

    Cricenti, A; Colonna, S; Girasole, M; Gori, P; Ronci, F; Longo, G; Dinarelli, S; Luce, M; Rinaldi, M; Ortenzi, M

    2011-01-01

    A review of the activity of scanning probe microscopy at our Institute is presented, going from instrumentation to software development of scanning tunnelling microscopy, atomic force microscopy and scanning near-field optical microscopy (SNOM). Some of the most important experiments in material science and biology performed by our group through the years with these SPM techniques will be presented. Finally, infrared applications by coupling a SNOM with a free electron laser will also be presented.

  14. Is scanning in probed order recall articulatory?

    Science.gov (United States)

    Farrell, Simon; Lelièvre, Anna

    2009-09-01

    We consider how theories of serial recall might apply to other short-term memory tasks involving recall of order. In particular, we consider the possibility that when participants are cued to recall an item at an arbitrary position in a sequence, they covertly serially recall the list up to the cued position. One question is whether such "scanning" is articulatory in nature. Two experiments are presented in which the syllabic length of words preceding and following target positions were manipulated, to test the prediction of an articulatory-based mechanism that time to recall an item at a particular position will depend on the number of preceding long words. Although latency was dependent on target position, no word length effects on latency were observed. Additionally, the effects of word length on accuracy replicate recent demonstrations in serial recall that recall accuracy is dependent on the word length of all list items, not just that of target items, in line with distinctiveness assumptions. It is concluded that if scanning does occur, it is not carried out by covert or overt articulation.

  15. Four-probe measurements with a three-probe scanning tunneling microscope

    International Nuclear Information System (INIS)

    Salomons, Mark; Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A.

    2014-01-01

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe

  16. Four-probe measurements with a three-probe scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Salomons, Mark [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Martins, Bruno V. C.; Zikovsky, Janik; Wolkow, Robert A., E-mail: rwolkow@ualberta.ca [National Institute for Nanotechnology, National Research Council of Canada, Edmonton, Alberta T6G 2M9 (Canada); Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada)

    2014-04-15

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

  17. Four-probe measurements with a three-probe scanning tunneling microscope.

    Science.gov (United States)

    Salomons, Mark; Martins, Bruno V C; Zikovsky, Janik; Wolkow, Robert A

    2014-04-01

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

  18. Nanofabrication of magnetic scanned-probe microscope sensors

    International Nuclear Information System (INIS)

    Chong, B.K.

    2001-10-01

    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 Scanning Electromagnetic Force Microscopy (eMFM) were designed and constructed at the apex of Silicon attractive mode cantilever probes. The process demonstrates good control over sensor parameters. Results indicated controllability of Hall bar junction sizes (spatial resolution) to below 100nm and Coil diameter sizes to below 500nm with minimum sizes down to 50nm and 270nm respectively. The process has shown its flexibility to accommodate different material systems. The same technology was used to fabricate multiple devices such as double Hall bars on a tip as well as a small electro-magnet coil probe co-defined with the Hall probe to form a magnetic imaging / modification probe. A conventional Non-Contact mode AFM employing heterodyne interferometry and in-house built electronics was modified for SHPM and eMFM. These probes had been scanned over a commercial computer hard disk. These microscopes showed the capability of resolving magnetic bits and topographic information independently and simultaneously. All scanning 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

  19. Logarithmic axicon characterized by scanning optical probe system.

    Science.gov (United States)

    Cao, Zhaolou; Wang, Keyi; Wu, Qinglin

    2013-05-15

    A scanning optical probe system is proposed to measure a logarithmic axicon (LA) with subwavelength resolution. Multiple plane intensity profiles measured by a fiber probe are interpreted by solving an optimization problem to get the phase retardation function (PRF) of the LA. Experimental results show that this approach can accurately obtain the PRF with which the optical path difference of the generated quasi-nondiffracting beam in the propagation is calculated.

  20. Gold nanocone probes for near-field scanning optical microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zeeb, Bastian; Schaefer, Christian; Nill, Peter; Fleischer, Monika; Kern, Dieter P. [Institute of Applied Physics, University of Tuebingen, Auf der Morgenstelle 10, 72076 Tuebingen (Germany)

    2010-07-01

    Apertureless near-field scanning optical microscopy (ANSOM) provides the possibility to collect simultaneously high-resolution topographical and sub-diffraction limited optical information from a surface. When optically excited, the scanning probes act as optical antennae with a strong near-field enhancement near the tip apex. Spatial resolution and optical near-field enhancement depend strongly on the properties and geometry of the scanning probe - in particular on very sharp tip radii. Various possibilities for fabricating good antennae have been pursued. Most commonly, scanning probes consist of electrochemically etched gold wires which are sharp but not well-defined in geometry. We present two different approaches for ultra sharp and well-defined antennae based upon fabricating gold nanocones with a tip radius smaller than 10 nm which can be used in ANSOM. A transfer process is presented that can be used to attach single gold nanocones to non-metallic probes such as sharp glass fiber tips. Alternatively, new processes are presented to fabricate cones directly on pillars of different materials such as silicon or bismuth, which can be applied to cantilever tips for ANSOM scanning applications.

  1. Soft control of scanning probe microscope with high flexibility.

    Science.gov (United States)

    Liu, Zhenghui; Guo, Yuzheng; Zhang, Zhaohui; Zhu, Xing

    2007-01-01

    Most commercial scanning probe microscopes have multiple embedded digital microprocessors and utilize complex software for system control, which is not easily obtained or modified by researchers wishing to perform novel and special applications. In this paper, we present a simple and flexible control solution that just depends on software running on a single-processor personal computer with real-time Linux operating system to carry out all the control tasks including negative feedback, tip moving, data processing and user interface. In this way, we fully exploit the potential of a personal computer in calculating and programming, enabling us to manipulate the scanning probe as required without any special digital control circuits and related technical know-how. This solution has been successfully applied to a homemade ultrahigh vacuum scanning tunneling microscope and a multiprobe scanning tunneling microscope.

  2. In Situ Scanning Probe Microscopy and New Perspectives in Analytical Chemistry

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Zhang, Jingdong; Chi, Qijin

    1999-01-01

    The resolution of scanning probe microscopies is unpresedented but the techniques are fraught with limitations as analytical tools. These limitations and their relationship to the physical mechanisms of image contrast are first discussed. Some new options based on in situ STM, which hold prospect...

  3. Nanomanipulation and nanofabrication with multi-probe scanning tunneling microscope: from individual atoms to nanowires.

    Science.gov (United States)

    Qin, Shengyong; Kim, Tae-Hwan; Wang, Zhouhang; Li, An-Ping

    2012-06-01

    The wide variety of nanoscale structures and devices demands novel tools for handling, assembly, and fabrication at nanoscopic positioning precision. The manipulation tools should allow for in situ characterization and testing of fundamental building blocks, such as nanotubes and nanowires, as they are built into functional devices. In this paper, a bottom-up technique for nanomanipulation and nanofabrication is reported by using a 4-probe scanning tunneling microscope (STM) combined with a scanning electron microscope (SEM). The applications of this technique are demonstrated in a variety of nanosystems, from manipulating individual atoms to bending, cutting, breaking carbon nanofibers, and constructing nanodevices for electrical characterizations. The combination of the wide field of view of SEM, the atomic position resolution of STM, and the flexibility of multiple scanning probes is expected to be a valuable tool for rapid prototyping in the nanoscience and nanotechnology.

  4. Scanning tunneling microscopy III theory of STM and related scanning probe methods

    CERN Document Server

    Güntherodt, Hans-Joachim

    1996-01-01

    Scanning Tunneling Microscopy III provides a unique introduction to the theoretical foundations of scanning tunneling microscopy and related scanning probe methods. The different theoretical concepts developed in the past are outlined, and the implications of the theoretical results for the interpretation of experimental data are discussed in detail. Therefore, this book serves as a most useful guide for experimentalists as well as for theoreticians working in the filed of local probe methods. In this second edition the text has been updated and new methods are discussed.

  5. The art of SPM : scanning probe microscopy in materials science

    NARCIS (Netherlands)

    Loos, J.

    2005-01-01

    In this Progress Report, outstanding scientific applications of scanning probe microscopy (SPM) in the field of materials science and the latest technique developments are introduced and discussed. Besides being able to image the organization of matter with sub-nanometer resolution, SPM, owing to

  6. Surface chemical reactions probed with scanning force microscopy

    NARCIS (Netherlands)

    Werts, M.P L; van der Vegte, E.W.; Hadziioannou, G

    1997-01-01

    In this letter we report the study of surface chemical reactions with scanning force microscopy (SFM) with chemical specificity. Using chemically modified SFM probes, we can determine the local surface reaction conversion during a chemical surface modification. The adhesion forces between a

  7. Laser scanning dental probe for endodontic root canal treatment

    Science.gov (United States)

    Blank, Molly A. B.; Friedrich, Michal; Hamilton, Jeffrey D.; Lee, Peggy; Berg, Joel; Seibel, Eric J.

    2011-03-01

    Complications that arise during endodontic procedures pose serious threats to the long-term integrity and health of the tooth. Potential complexities of root canals include residual pulpal tissue, cracks, mesial-buccal 2 and accessory canals. In the case of a failed root canal, a successful apicoectomy can be jeopardized by isthmuses, accessory canals, and root microfracture. Confirming diagnosis using a small imaging probe would allow proper treatment and prevent retreatment of endodontic procedures. An ultrathin and flexible laser scanning endoscope of 1.2 to 1.6mm outer diameter was used in vitro to image extracted teeth with varied root configurations. Teeth were opened using a conventional bur and high speed drill. Imaging within the opened access cavity clarified the location of the roots where canal filing would initiate. Although radiographs are commonly used to determine the root canal size, position, and shape, the limited 2D image perspective leaves ambiguity that could be clarified if used in conjunction with a direct visual imaging tool. Direct visualization may avoid difficulties in locating the root canal and reduce the number of radiographs needed. A transillumination imaging device with the separated illumination and light collection functions rendered cracks visible in the prepared teeth that were otherwise indiscernible using reflected visible light. Our work demonstrates that a small diameter endoscope with high spatial resolution may significantly increase the efficiency and success of endodontic procedures.

  8. Quadratic electromechanical strain in silicon investigated by scanning probe microscopy

    Science.gov (United States)

    Yu, Junxi; Esfahani, Ehsan Nasr; Zhu, Qingfeng; Shan, Dongliang; Jia, Tingting; Xie, Shuhong; Li, Jiangyu

    2018-04-01

    Piezoresponse force microscopy (PFM) is a powerful tool widely used to characterize piezoelectricity and ferroelectricity at the nanoscale. However, it is necessary to distinguish microscopic mechanisms between piezoelectricity and non-piezoelectric contributions measured by PFM. In this work, we systematically investigate the first and second harmonic apparent piezoresponses of a silicon wafer in both vertical and lateral modes, and we show that it exhibits an apparent electromechanical response that is quadratic to the applied electric field, possibly arising from ionic electrochemical dipoles induced by the charged probe. As a result, the electromechanical response measured is dominated by the second harmonic response in the vertical mode, and its polarity can be switched by the DC voltage with the evolving coercive field and maximum amplitude, in sharp contrast to typical ferroelectric materials we used as control. The ionic activity in silicon is also confirmed by the scanning thermo-ionic microscopy measurement, and the work points toward a set of methods to distinguish true piezoelectricity from the apparent ones.

  9. Analysis of main artifacts in scanning probe microscopy (1)

    International Nuclear Information System (INIS)

    Alekperov, S.D.; Alekperov, S.D.

    2012-01-01

    The analysis of experiment carrying methodology in the scanning probe microscopy (SPM) region is carried out, the main parameters influencing on image quality are revealed. In order to reveal the artifact reason the main components of SPM signal which are divided on 5 groups : the useful signal; noises connected with external influences and temperature drift; distortions connected with piezoceramics and piezo-scanner non-ideality; probe geometry influence; apparatus noises are considered. The main methods of removal and minimization of the given artifacts are considered. The second and third groups of main components of SPM signal are considered in the articles first part

  10. RTSPM: real-time Linux control software for scanning probe microscopy.

    Science.gov (United States)

    Chandrasekhar, V; Mehta, M M

    2013-01-01

    Real time computer control is an essential feature of scanning probe microscopes, which have become important tools for the characterization and investigation of nanometer scale samples. Most commercial (and some open-source) scanning probe data acquisition software uses digital signal processors to handle the real time data processing and control, which adds to the expense and complexity of the control software. We describe here scan control software that uses a single computer and a data acquisition card to acquire scan data. The computer runs an open-source real time Linux kernel, which permits fast acquisition and control while maintaining a responsive graphical user interface. Images from a simulated tuning-fork based microscope as well as a standard topographical sample are also presented, showing some of the capabilities of the software.

  11. Geometrical modelling of scanning probe microscopes and characterization of errors

    International Nuclear Information System (INIS)

    Marinello, F; Savio, E; Bariani, P; Carmignato, S

    2009-01-01

    Scanning probe microscopes (SPMs) allow quantitative evaluation of surface topography with ultra-high resolution, as a result of accurate actuation combined with the sharpness of tips. SPMs measure sequentially, by scanning surfaces in a raster fashion: topography maps commonly consist of data sets ideally reported in an orthonormal rectilinear Cartesian coordinate system. However, due to scanning errors and measurement distortions, the measurement process is far from the ideal Cartesian condition. The paper addresses geometrical modelling of the scanning system dynamics, presenting a mathematical model which describes the surface metric x-, y- and z- coordinates as a function of the measured x'-, y'- and z'-coordinates respectively. The complete mathematical model provides a relevant contribution to characterization and calibration, and ultimately to traceability, of SPMs, when applied for quantitative characterization

  12. Band excitation method applicable to scanning probe microscopy

    Science.gov (United States)

    Jesse, Stephen [Knoxville, TN; Kalinin, Sergei V [Knoxville, TN

    2010-08-17

    Methods and apparatus are described for scanning probe microscopy. A method includes generating a band excitation (BE) signal having finite and predefined amplitude and phase spectrum in at least a first predefined frequency band; exciting a probe using the band excitation signal; obtaining data by measuring a response of the probe in at least a second predefined frequency band; and extracting at least one relevant dynamic parameter of the response of the probe in a predefined range including analyzing the obtained data. The BE signal can be synthesized prior to imaging (static band excitation), or adjusted at each pixel or spectroscopy step to accommodate changes in sample properties (adaptive band excitation). An apparatus includes a band excitation signal generator; a probe coupled to the band excitation signal generator; a detector coupled to the probe; and a relevant dynamic parameter extractor component coupled to the detector, the relevant dynamic parameter extractor including a processor that performs a mathematical transform selected from the group consisting of an integral transform and a discrete transform.

  13. Novel scanning probe microscope instrumentation with applications in nanotechnology

    International Nuclear Information System (INIS)

    Humphry, M.J.

    2000-10-01

    A versatile scanning probe microscope controller has been constructed. Its suitability for the control of a range of different scanning probe microscope heads has been demonstrated. These include an ultra high vacuum scanning tunnelling microscope, with which atomic resolution images of Si surfaces was obtained, a custom-built atomic force microscope, and a custom-built photon emission scanning tunnelling microscope. The controller has been designed specifically to facilitate data acquisition during molecular manipulation experiments. Using the controller, the fullerene molecule C 60 has been successfully manipulated on Si(100)-2x1 surfaces and detailed data has been acquired during the manipulation process. Evidence for two distinct modes of manipulation have been observed. A repulsive mode with success rates up to 90% was found to occur with tunnel gap impedances below 2GΩ, while between 2GΩ and 8GΩ attractive manipulation events were observed, with a maximum success rate of ∼8%. It was also found that the step size between feedback updates had a significant effect on tip stability, and that dwell time of the STM tip at each data point had a critical effect on manipulation probability. A multi-function scanning probe microscope head has been developed capable of operation as a scanning tunnelling microscope and an atomic force microscope in vacuum and a magnetic field of 7T. The custom-built controller also presented here was used to control the head. A three-axis inertial sliding motor was developed for the head, capable of reproducible step sizes of <1000A. In addition, an optical fibre interferometer was constructed with a sensitivity of 0.2A/√Hz. Preliminary development of a magnetic resonance force microscope mode has also been performed, with initial results showing such a system to be feasible. (author)

  14. Multifrequency scanning probe microscopy study of nanodiamond agglomerates

    Science.gov (United States)

    Aravind, Vasudeva; Lippold, Stephen; Li, Qian; Strelcov, Evgheny; Okatan, Baris; Legum, Benjamin; Kalinin, Sergei; Clarion University Team; Oak Ridge National Laboratory Team

    Due to their rich surface chemistry and excellent mechanical properties and non-toxic nature, nanodiamond particles have found applications such as biomedicine, tribology and lubrication, targeted drug delivery systems, tissue scaffolds and surgical implants. Although single nanodiamond particles have diameters about 4-5nm, they tend to form agglomerates. While these agglomerates can be useful for some purposes, many applications of nanodiamonds require single particle, disaggregated nanodiamonds. This work is oriented towards studying forces and interactions that contribute to agglomeration in nanodiamonds. In this work, using multifrequency scanning probe microscopy techniques, we show that agglomerate sizes can vary between 50-100nm in raw nanodiamonds. Extremeties of particles and Interfaces between agglomerates show dissipative forces with scanning probe microscope tip, indicating agglomerates could act as points of increased adhesion, thus reducing lubricating efficiency when nanodiamonds are used as lubricant additives. This research was conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.

  15. Time dependence of the natural passivation process on AISI 304 in an alkaline medium: Atomic force microscopy and scanning Kelvin probe force microscopy as additional tools to electrochemical impedance spectroscopy

    Science.gov (United States)

    Benaioun, N. E.; Maafa, I.; Florentin, A.; Denys, E.; Hakiki, N. E.; Moulayat, N.; Bubendorff, J. L.

    2018-04-01

    Thin surface films formed on AISI 304 samples in an alkaline solution of pH = 13 are studied by atomic force microscopy (AFM), scanning Kelvin probe force microscopy (SKPFM) and electrochemical impedance spectroscopy (EIS) as a function of immersion time. The results reveal that changes on EIS diagrams correspond to topographical modifications on the sample surface as shown by AFM. Both techniques are therefore complementary. The oxide layer is chemically homogenous as shown by SKPFM imaging and our ultra-thin passive layer is an efficient barrier against corrosion.

  16. Processing of Graphene combining Optical Detection and Scanning Probe Lithography

    Directory of Open Access Journals (Sweden)

    Zimmermann Sören

    2015-01-01

    Full Text Available This paper presents an experimental setup tailored for robotic processing of graphene with in-situ vision based control. A robust graphene detection approach is presented applying multiple image processing operations of the visual feedback provided by a high-resolution light microscope. Detected graphene flakes can be modified using a scanning probe based lithographical process that is directly linked to the in-situ optical images. The results of this process are discussed with respect to further application scenarios.

  17. Scanning probe lithography for fabrication of Ti metal nanodot arrays

    International Nuclear Information System (INIS)

    Jung, B.; Jo, W.; Gwon, M.J.; Lee, E.; Kim, D.-W.

    2010-01-01

    We report fabrication of Ti metal nanodot arrays by scanning probe microscopic indentation. A thin poly-methylmethacrylate (PMMA) layer was spin-coated on Si substrates with thickness of 70 nm. Nanometer-size pore arrays were formed by indenting the PMMA layer using a cantilever of a scanning probe microscope. Protuberances with irregular boundaries appeared during the indentation process. Control of approach and pulling-out speed during indentation was able to dispose of the protrusions. Ti metal films were deposited on the patterned PMMA layers by a radio-frequency sputtering method and subsequently lifted off to obtain metal nanodot arrays. The fabricated metal nanodot arrays have 200 nm of diameter and 500 nm of interdistance, which corresponds to a density of 4x10 8 /cm 2 . Scanning probe-based measurement of current-voltage (I-V) behaviors for a single Ti metal nanodot showed asymmetric characteristics. Applying external bias is likely to induce oxidation of Ti metal, since the conductance decreased and volume change of the dots was observed. I-V behaviors of Ti metal nanodots by conventional e-beam lithography were also characterized for comparison.

  18. Potential Applications of Scanning Probe Microscopy in Forensic Science

    Energy Technology Data Exchange (ETDEWEB)

    Watson, G S [Nanoscale Science and Technology Centre, School of Science, Griffith University, Kessels Rd, Nathan, QLD, 4111 (Australia); Watson, J A [Nanoscale Science and Technology Centre, School of Science, Griffith University, Kessels Rd, Nathan, QLD, 4111 (Australia)

    2007-04-15

    The forensic community utilises a myriad of techniques to investigate a wide range of materials, from paint flakes to DNA. The various microscopic techniques have provided some of the greatest contributions, e.g., FT-IR (Fourier-transform infrared) microspectroscopy utilised in copy toner discrimination, multi-layer automobile paint fragment examination, etc, SEM-EDA (scanning electron microscopy with energy dispersive analysis) used to investigate glass fragments, fibers, and explosives, and SEM in microsampling for elemental analysis, just to name a few. This study demonstrates the ability of the Scanning Probe Microscope (SPM) to analyse human fingerprints on surfaces utilising a step-and-scan feature, enabling analysis of a larger field-of-view. We also extend a line crossings study by incorporating height analysis and surface roughness measurements. The study demonstrates the potential for SPM techniques to be utilised for forensic analysis which could complement the more traditional methodologies used in such investigations.

  19. Potential Applications of Scanning Probe Microscopy in Forensic Science

    International Nuclear Information System (INIS)

    Watson, G S; Watson, J A

    2007-01-01

    The forensic community utilises a myriad of techniques to investigate a wide range of materials, from paint flakes to DNA. The various microscopic techniques have provided some of the greatest contributions, e.g., FT-IR (Fourier-transform infrared) microspectroscopy utilised in copy toner discrimination, multi-layer automobile paint fragment examination, etc, SEM-EDA (scanning electron microscopy with energy dispersive analysis) used to investigate glass fragments, fibers, and explosives, and SEM in microsampling for elemental analysis, just to name a few. This study demonstrates the ability of the Scanning Probe Microscope (SPM) to analyse human fingerprints on surfaces utilising a step-and-scan feature, enabling analysis of a larger field-of-view. We also extend a line crossings study by incorporating height analysis and surface roughness measurements. The study demonstrates the potential for SPM techniques to be utilised for forensic analysis which could complement the more traditional methodologies used in such investigations

  20. Scanning probes for new energy materials: probing local structure and function

    NARCIS (Netherlands)

    Balke, N.; Bonnell, D.; Ginger, D.S.; Kemerink, M.

    2012-01-01

    The design and control of materials properties, often at the nanoscale, are the foundation of many new strategies for energy generation, storage, and efficiency. Scanning probe microscopy (SPM) has evolved into a very large toolbox for the characterization of properties spanning size scales from

  1. Gwyscan: a library to support non-equidistant scanning probe microscope measurements

    International Nuclear Information System (INIS)

    Klapetek, Petr; Grolich, Petr; Valtr, Miroslav; Yacoot, Andrew; Nečas, David

    2017-01-01

    We present a software library and related methodology for enabling easy integration of adaptive step (non-equidistant) scanning techniques into metrological scanning probe microscopes or scanning probe microscopes where individual x , y position data are recorded during measurements. Scanning with adaptive steps can reduce the amount of data collected in SPM measurements thereby leading to faster data acquisition, a smaller amount of data collection required for a specific analytical task and less sensitivity to mechanical and thermal drift. Implementation of adaptive scanning routines into a custom built microscope is not normally an easy task: regular data are much easier to handle for previewing (e.g. levelling) and storage. We present an environment to make implementation of adaptive scanning easier for an instrument developer, specifically taking into account data acquisition approaches that are used in high accuracy microscopes as those developed by National Metrology Institutes. This includes a library with algorithms written in C and LabVIEW for handling data storage, regular mesh preview generation and planning the scan path on basis of different assumptions. A set of modules for Gwyddion open source software for handling these data and for their further analysis is presented. Using this combination of data acquisition and processing tools one can implement adaptive scanning in a relatively easy way into an instrument that was previously measuring on a regular grid. The performance of the presented approach is shown and general non-equidistant data processing steps are discussed. (paper)

  2. Gwyscan: a library to support non-equidistant scanning probe microscope measurements

    Science.gov (United States)

    Klapetek, Petr; Yacoot, Andrew; Grolich, Petr; Valtr, Miroslav; Nečas, David

    2017-03-01

    We present a software library and related methodology for enabling easy integration of adaptive step (non-equidistant) scanning techniques into metrological scanning probe microscopes or scanning probe microscopes where individual x, y position data are recorded during measurements. Scanning with adaptive steps can reduce the amount of data collected in SPM measurements thereby leading to faster data acquisition, a smaller amount of data collection required for a specific analytical task and less sensitivity to mechanical and thermal drift. Implementation of adaptive scanning routines into a custom built microscope is not normally an easy task: regular data are much easier to handle for previewing (e.g. levelling) and storage. We present an environment to make implementation of adaptive scanning easier for an instrument developer, specifically taking into account data acquisition approaches that are used in high accuracy microscopes as those developed by National Metrology Institutes. This includes a library with algorithms written in C and LabVIEW for handling data storage, regular mesh preview generation and planning the scan path on basis of different assumptions. A set of modules for Gwyddion open source software for handling these data and for their further analysis is presented. Using this combination of data acquisition and processing tools one can implement adaptive scanning in a relatively easy way into an instrument that was previously measuring on a regular grid. The performance of the presented approach is shown and general non-equidistant data processing steps are discussed.

  3. Graphene quantum dots probed by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Morgenstern, Markus; Freitag, Nils; Nent, Alexander; Nemes-Incze, Peter; Liebmann, Marcus [II. Institute of Physics B and JARA-FIT, RWTH Aachen University, Aachen (Germany)

    2017-11-15

    Scanning tunneling spectroscopy results probing the electronic properties of graphene quantum dots are reviewed. After a short summary of the study of squared wave functions of graphene quantum dots on metal substrates, we firstly present data where the Landau level gaps caused by a perpendicular magnetic field are used to electrostatically confine electrons in monolayer graphene, which are probed by the Coulomb staircase revealing the consecutive charging of a quantum dot. It turns out that these quantum dots exhibit much more regular charging sequences than lithographically confined ones. Namely, the consistent grouping of charging peaks into quadruplets, both, in the electron and hole branch, portrays a regular orbital splitting of about 10meV. At low hole occupation numbers, the charging peaks are, partly, additionally grouped into doublets. The spatially varying energy separation of the doublets indicates a modulation of the valley splitting by the underlying BN substrate. We outline that this property might be used to eventually tune the valley splitting coherently. Afterwards, we describe graphene quantum dots with multiple contacts produced without lithographic resist, namely by local anodic oxidation. Such quantum dots target the goal to probe magnetotransport properties during the imaging of the corresponding wave functions by scanning tunneling spectroscopy. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Vortex imaging in superconducting films by scanning Hall probe microscopy

    International Nuclear Information System (INIS)

    Oral, A.; Bending, S.J.; Humphreys, R.G.

    1996-01-01

    The authors have used a low noise Scanning Hall Probe Microscope (SHPM) to study vortex structures in superconducting films. The microscope has high magnetic field (∼2.9 x 10 -8 T/√Hz at 77K) and spatial resolution, ∼0.85 μm. Magnetic field profiles of single vortices in High T c YBa 2 Cu 3 O 7-δ thin films have been successfully measured and the microscopic penetration depth of the superconductor has been extracted as a function of temperature. Flux penetration into the superconductor has been imaged in real time (∼8s/frame)

  5. Modeling the hysteresis of a scanning probe microscope

    DEFF Research Database (Denmark)

    Dirscherl, Kai; Garnæs, Jørgen; Nielsen, L.

    2000-01-01

    Most scanning probe microscopes use piezoelectric actuators in open loop configurations. Therefore a major problem related to these instruments is the image distortion due to the hysteresis effect of the piezo. In order to eliminate the distortions, cost effective software control based on a model...... for hysteresis can be applied to the scanner. We describe a new rate-independent model for the hysteresis of a piezo scanner. Two reference standards were used to determine the accuracy of the model; a one-dimensional grating with a period of 3.0 mum and a two-dimensional grating with 200 nm pitch...

  6. Scanning Hall probe microscopy of a diluted magnetic semiconductor

    International Nuclear Information System (INIS)

    Kweon, Seongsoo; Samarth, Nitin; Lozanne, Alex de

    2009-01-01

    We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga 0.94 Mn 0.06 As films grown by molecular beam epitaxy. We find that the magnetic domains are 2-4 μm wide and fairly stable with temperature. Magnetic clusters are observed above T C , which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

  7. Scanning Hall probe microscopy of a diluted magnetic semiconductor

    Science.gov (United States)

    Kweon, Seongsoo; Samarth, Nitin; de Lozanne, Alex

    2009-05-01

    We have measured the micromagnetic properties of a diluted magnetic semiconductor as a function of temperature and applied field with a scanning Hall probe microscope built in our laboratory. The design philosophy for this microscope and some details are described. The samples analyzed in this work are Ga0.94Mn0.06As films grown by molecular beam epitaxy. We find that the magnetic domains are 2-4 μm wide and fairly stable with temperature. Magnetic clusters are observed above TC, which we ascribe to MnAs defects too small and sparse to be detected by a superconducting quantum interference device magnetometer.

  8. Multiple-scanning-probe tunneling microscope with nanoscale positional recognition function.

    Science.gov (United States)

    Higuchi, Seiji; Kuramochi, Hiromi; Laurent, Olivier; Komatsubara, Takashi; Machida, Shinichi; Aono, Masakazu; Obori, Kenichi; Nakayama, Tomonobu

    2010-07-01

    Over the past decade, multiple-scanning-probe microscope systems with independently controlled probes have been developed for nanoscale electrical measurements. We developed a quadruple-scanning-probe tunneling microscope (QSPTM) that can determine and control the probe position through scanning-probe imaging. The difficulty of operating multiple probes with submicrometer precision drastically increases with the number of probes. To solve problems such as determining the relative positions of the probes and avoiding of contact between the probes, we adopted sample-scanning methods to obtain four images simultaneously and developed an original control system for QSPTM operation with a function of automatic positional recognition. These improvements make the QSPTM a more practical and useful instrument since four images can now be reliably produced, and consequently the positioning of the four probes becomes easier owing to the reduced chance of accidental contact between the probes.

  9. Probing superconductors. Spectroscopic-imaging scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Hanaguri, Tetsuo

    2011-01-01

    Discovery of high-temperature superconductivity in a cuprate triggered developments of various spectroscopic tools which have been utilized to elucidate electronic states of this mysterious compound. Particularly, angle-resolved photoemission spectroscopy and scanning-tunneling microscopy/spectroscopy are improved considerably. It is now possible to map the superconducting gap in both momentum and real spaces using these two techniques. Here we review spectroscopic-imaging scanning tunneling microscopy which is able to explore momentum-space phase structure of the superconducting gap, as well as real-space structure. Applications of this technique to a cuprate and an iron-based superconductor are discussed. (author)

  10. Optical and electrical characterization at the nanoscale with a transparent probe of a scanning tunnelling microscope

    International Nuclear Information System (INIS)

    Sychugov, Ilya; Omi, Hiroo; Murashita, Tooru; Kobayashi, Yoshihiro

    2009-01-01

    A new type of scanning probe microscope, combining features of the scanning tunnelling microscope, the scanning tunnelling luminescence microscope with a transparent probe and the aperture scanning near-field optical microscope, is described. Proof-of-concept experiments were performed under ultrahigh vacuum conditions at varying temperature on GaAs/AlAs heterostructures.

  11. Scanning probe microscopy with vertically oriented cantilevers made easy

    International Nuclear Information System (INIS)

    Valdrè, G; Moro, D; Ulian, G

    2012-01-01

    Non-contact imaging in scanning probe microscopy (SPM) is becoming of great importance in particular for imaging biological matter and in general soft materials. Transverse dynamic force microscopy (TDFM) is an SPM-based methodology that exploiting a cantilever oriented in a vertical configuration with respect to the sample surface may work with very low tip to sample interaction forces. The probe is oscillated parallel to the sample surface, usually by a piezoelectric element. However, this methodology often requires complex microscope setups and detection systems, so it is usually developed in specific laboratories as a prototype microscope. Here, we present a very simple device that easily enables a commercial SPM head to be oriented in such a way to have the cantilever long axis perpendicular to the sample surface. No modifications of the SPM hardware and software are required and commercial available cantilevers can be used as probes. Performance tests using polystyrene spheres, muscovite crystallographic steps and DNA single molecules were successful and all resulted in agreement with other TDFM and SPM observations demonstrating the reliability of the device. (paper)

  12. High throughput, parallel scanning probe microscope for nanometrology and nanopatterning applications

    NARCIS (Netherlands)

    Sadeghian Marnani, H.; Paul, P.C.; Herfst, R.W.; Dekker, A.; Winters, J.; Maturova, K.

    2017-01-01

    Scanning Probe microscope (SPM) is an important nanoinstrument for several applications such as bioresearch, metrology, inspection and nanopatterning. Single SPM is associated with relatively slow rate of scanning and low throughput measurement, thus not being suitable for scanning large samples

  13. Nanolithography and nanochemistry utilizing scanning probe techniques: directed self-assembly of sub-micrometer-sized structures by scanning probe lithography defined templates

    NARCIS (Netherlands)

    Wouters, D.; Sturms, J.P.E.; Schubert, U.S.

    2004-01-01

    The octadecyl trichlorosilane (OTS) monolayer was formed on Si carrier, and the template regulated by a local probe oxidation method from this was produced using a scanning probe lithography. The local probe oxidation was done by moving an AFM tip along an axle line. When the chip contacts a OTS

  14. Piezoresistor-equipped fluorescence-based cantilever probe for near-field scanning.

    Science.gov (United States)

    Kan, Tetsuo; Matsumoto, Kiyoshi; Shimoyama, Isao

    2007-08-01

    Scanning near-field optical microscopes (SNOMs) with fluorescence-based probes are promising tools for evaluating the optical characteristics of nanoaperture devices used for biological investigations, and this article reports on the development of a microfabricated fluorescence-based SNOM probe with a piezoresistor. The piezoresistor was built into a two-legged root of a 160-microm-long cantilever. To improve the displacement sensitivity of the cantilever, the piezoresistor's doped area was shallowly formed on the cantilever surface. A fluorescent bead, 500 nm in diameter, was attached to the bottom of the cantilever end as a light-intensity-sensitive material in the visible-light range. The surface of the scanned sample was simply detected by the probe's end being displaced by contact with the sample. Measuring displacements piezoresistively is advantageous because it eliminates the noise arising from the use of the optical-lever method and is free of any disturbance in the absorption or the emission spectrum of the fluorescent material at the probe tip. The displacement sensitivity was estimated to be 6.1 x 10(-6) nm(-1), and the minimum measurable displacement was small enough for near-field measurement. This probe enabled clear scanning images of the light field near a 300 x 300 nm(2) aperture to be obtained in the near-field region where the tip-sample distance is much shorter than the light wavelength. This scanning result indicates that the piezoresistive way of tip-sample distance regulation is effective for characterizing nanoaperture optical devices.

  15. Integrated Confocal and Scanning Probe Microscopy for Biomedical Research

    Directory of Open Access Journals (Sweden)

    B.J. Haupt

    2006-01-01

    Full Text Available Atomic force microscopy (AFM continues to be developed, not only in design, but also in application. The new focus of using AFM is changing from pure material to biomedical studies. More frequently, it is being used in combination with other optical imaging methods, such as confocal laser scanning microscopy (CLSM and fluorescent imaging, to provide a more comprehensive understanding of biological systems. To date, AFM has been used increasingly as a precise micromanipulator, probing and altering the mechanobiological characteristics of living cells and tissues, in order to examine specific, receptor-ligand interactions, material properties, and cell behavior. In this review, we discuss the development of this new hybrid AFM, current research, and potential applications in diagnosis and the detection of disease.

  16. Probing Free-Energy Surfaces with Differential Scanning Calorimetry

    Science.gov (United States)

    Sanchez-Ruiz, Jose M.

    2011-05-01

    Many aspects of protein folding can be understood in terms of projections of the highly dimensional energy landscape onto a few (or even only one) particularly relevant coordinates. These free-energy surfaces can be probed conveniently from experimental differential scanning calorimetry (DSC) thermograms, as DSC provides a direct relation with the protein partition function. Free-energy surfaces thus obtained are consistent with two fundamental scenarios predicted by the energy-landscape perspective: (a) well-defined macrostates separated by significant free-energy barriers, in some cases, and, in many other cases, (b) marginal or even vanishingly small barriers, which furthermore show a good correlation with kinetics for fast- and ultrafast-folding proteins. Overall, the potential of DSC to assess free-energy surfaces for a wide variety of proteins makes it possible to address fundamental issues, such as the molecular basis of the barrier modulations produced by natural selection in response to functional requirements or to ensure kinetic stability.

  17. NATO Advanced Study Institute on Scanning Probe Microscopy : Characterization, Nanofabrication and Device Application of Functional Materials

    CERN Document Server

    Vilarinho, Paula Maria; Kingon, Angus; Scanning Probe Microscopy : Characterization, Nanofabrication and Device Application of Functional Materials

    2005-01-01

    As the characteristic dimensions of electronic devices continue to shrink, the ability to characterize their electronic properties at the nanometer scale has come to be of outstanding importance. In this sense, Scanning Probe Microscopy (SPM) is becoming an indispensable tool, playing a key role in nanoscience and nanotechnology. SPM is opening new opportunities to measure semiconductor electronic properties with unprecedented spatial resolution. SPM is being successfully applied for nanoscale characterization of ferroelectric thin films. In the area of functional molecular materials it is being used as a probe to contact molecular structures in order to characterize their electrical properties, as a manipulator to assemble nanoparticles and nanotubes into simple devices, and as a tool to pattern molecular nanostructures. This book provides in-depth information on new and emerging applications of SPM to the field of materials science, namely in the areas of characterisation, device application and nanofabrica...

  18. A scanning fluid dynamic gauging technique for probing surface layers

    International Nuclear Information System (INIS)

    Gordon, Patrick W; Chew, Y M John; Wilson, D Ian; Brooker, Anju D M; York, David W

    2010-01-01

    Fluid dynamic gauging (FDG) is a technique for measuring the thickness of soft solid deposit layers immersed in a liquid environment, in situ and in real time. This paper details the performance of a novel automated, scanning FDG probe (sFDG) which allows the thickness of a sample layer to be monitored at several points during an experiment, with a resolution of ±5 µm. Its application is demonstrated using layers of gelatine, polyvinyl alcohol (PVA) and baked tomato purée deposits. Swelling kinetics, as well as deformation behaviour—based on knowledge of the stresses imposed on the surface by the gauging flow—can be determined at several points, affording improved experimental data. The use of FDG as a surface scanning technique, operating as a fluid mechanical analogue of atomic force microscopy on a millimetre length scale, is also demonstrated. The measurement relies only on the flow behaviour, and is thus suitable for use in opaque fluids, does not contact the surface itself and does not rely on any specific physical properties of the surface, provided it is locally stiff

  19. Electromechanical response of amorphous LaAlO3 thin film probed by scanning probe microscopies

    Science.gov (United States)

    Borowiak, Alexis S.; Baboux, Nicolas; Albertini, David; Vilquin, Bertrand; Saint Girons, Guillaume; Pelloquin, Sylvain; Gautier, Brice

    2014-07-01

    The electromechanical response of a 3 nm thick amorphous LaAlO3 layer obtained by molecular beam epitaxy has been studied using scanning probe microscopies. Although this kind of sample is not ferroelectric due to its amorphous nature, the resulting images are identical to what is generally obtained on truly ferroelectric samples probed by piezoresponse force microscopy: domains of apparently opposite polarisation are detected, and perfect, square shaped hysteresis loops are recorded. Moreover, written patterns are stable within 72 h. We discuss in the general case the possible origins of this behaviour in terms of charge injection, ionic conduction and motion of oxygen vacancies. In the case presented in this paper, since the writing process has been conducted with applied voltages lower than the injection threshold measured by conductive atomic force Microscopy, allowing to withdraw the hypothesis of charge injection in the sample, we propose that a bistable distribution of oxygen vacancies is responsible for this contrast.

  20. Electromechanical response of amorphous LaAlO3 thin film probed by scanning probe microscopies

    International Nuclear Information System (INIS)

    Borowiak, Alexis S.; Baboux, Nicolas; Albertini, David; Gautier, Brice; Vilquin, Bertrand; Saint Girons, Guillaume; Pelloquin, Sylvain

    2014-01-01

    The electromechanical response of a 3 nm thick amorphous LaAlO 3 layer obtained by molecular beam epitaxy has been studied using scanning probe microscopies. Although this kind of sample is not ferroelectric due to its amorphous nature, the resulting images are identical to what is generally obtained on truly ferroelectric samples probed by piezoresponse force microscopy: domains of apparently opposite polarisation are detected, and perfect, square shaped hysteresis loops are recorded. Moreover, written patterns are stable within 72 h. We discuss in the general case the possible origins of this behaviour in terms of charge injection, ionic conduction and motion of oxygen vacancies. In the case presented in this paper, since the writing process has been conducted with applied voltages lower than the injection threshold measured by conductive atomic force Microscopy, allowing to withdraw the hypothesis of charge injection in the sample, we propose that a bistable distribution of oxygen vacancies is responsible for this contrast.

  1. Sparse sampling and reconstruction for electron and scanning probe microscope imaging

    Science.gov (United States)

    Anderson, Hyrum; Helms, Jovana; Wheeler, Jason W.; Larson, Kurt W.; Rohrer, Brandon R.

    2015-07-28

    Systems and methods for conducting electron or scanning probe microscopy are provided herein. In a general embodiment, the systems and methods for conducting electron or scanning probe microscopy with an undersampled data set include: driving an electron beam or probe to scan across a sample and visit a subset of pixel locations of the sample that are randomly or pseudo-randomly designated; determining actual pixel locations on the sample that are visited by the electron beam or probe; and processing data collected by detectors from the visits of the electron beam or probe at the actual pixel locations and recovering a reconstructed image of the sample.

  2. Correlated Raman micro-spectroscopy and scanning electron microscopy analyses of flame retardants in environmental samples: a micro-analytical tool for probing chemical composition, origin and spatial distribution.

    Science.gov (United States)

    Ghosal, Sutapa; Wagner, Jeff

    2013-07-07

    We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.

  3. Tools for Ultraspecific Probe/Primer Design

    National Research Council Canada - National Science Library

    Fofanov, Yurly

    2006-01-01

    .... Our approach will deliver DNA probes and PCR primers that have an unprecedentedly low probability of false positives or confusion by environmental background, and which resist evasion by threat agent engineering...

  4. Scanning probe microscopy of single Au ion implants in Si

    International Nuclear Information System (INIS)

    Vines, L.; Monakhov, E.; Maknys, K.; Svensson, B.G.; Jensen, J.; Hallen, A.; Kuznetsov, A. Yu.

    2006-01-01

    We have studied 5 MeV Au 2+ ion implantation with fluences between 7 x 10 7 and 2 x 10 8 cm -2 in Si by deep level transient spectroscopy (DLTS) and scanning capacitance microscopy (SCM). The DLTS measurements show formation of electrically active defects such as the two negative charge states of the divacancy (V 2 (=/-) and V 2 (-/0)) and the vacancy-oxygen (VO) center. It is observed that the intensity of the V 2 (=/-) peak is lower compared to that of V 2 (-/0) by a factor of 5. This has been attributed to a highly localized distribution of the defects along the ion tracks, which results in trapping of the carriers at V 2 (-/0) and incomplete occupancy of V 2 (=/-). The SCM measurements obtained in a plan view show a random pattern of regions with a reduced SCM signal for the samples implanted with fluence above 2 x 10 8 cm -2 . The reduced SCM signal is attributed to extra charges associated with acceptor states, such as V 2 (-/0), formed along the ion tracks in the bulk Si. Indeed, the electron emission rate from the V 2 (-/0) state is in the range of 10 kHz at room temperature, which is well below the probing frequency of the SCM measurements, resulting in 'freezing' of electrons at V 2 (-/0)

  5. Probing plasmons in three dimensions by combining complementary spectroscopies in a scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Hachtel, J A; Haglund, R F; Pantelides, S T; Marvinney, C; Mayo, D; Mouti, A; Lupini, A R; Chisholm, M F; Mu, R; Pennycook, S J

    2016-01-01

    The nanoscale optical response of surface plasmons in three-dimensional metallic nanostructures plays an important role in many nanotechnology applications, where precise spatial and spectral characteristics of plasmonic elements control device performance. Electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) within a scanning transmission electron microscope have proven to be valuable tools for studying plasmonics at the nanoscale. Each technique has been used separately, producing three-dimensional reconstructions through tomography, often aided by simulations for complete characterization. Here we demonstrate that the complementary nature of the two techniques, namely that EELS probes beam-induced electronic excitations while CL probes radiative decay, allows us to directly obtain a spatially- and spectrally-resolved picture of the plasmonic characteristics of nanostructures in three dimensions. The approach enables nanoparticle-by-nanoparticle plasmonic analysis in three dimensions to aid in the design of diverse nanoplasmonic applications. (paper)

  6. Simulation-aided design and fabrication of nanoprobes for scanning probe microscopy

    International Nuclear Information System (INIS)

    Liu, Bernard Haochih; Chang, Day-Bin

    2011-01-01

    We proposed and demonstrated a flexible and effective method to design and fabricate scanning probes for atomic force microscopy applications. Computer simulations were adopted to evaluate design specifications and desired performance of atomic force microscope (AFM) probes; the fabrication processes were guided by feedback from simulation results. Through design-simulation-fabrication iterations, tipless cantilevers and tapping mode probes were successfully made with errors as low as 2% in designed resonant frequencies. For tapping mode probes, the probe tip apex achieved a 10 nm radius of curvature without additional sharpening steps; tilt-compensated probes were also fabricated for better scanning performance. This method provides AFM users improved probe quality and practical guidelines for customized probes, which can support the development of novel scanning probe microscopy (SPM) applications. -- Research highlights: → We developed a design-simulation-fabrication strategy for customized AFM/SPM probes and demonstrated the results of tipless cantilever, sharpened probe tip, and tilt-compensated probe. → This simulation-aided method improved the geometry control and performance prediction of AFM probes; the error in resonant frequency was reduced to ∼2%. → Integration of simulation in design and fabrication of AFM probes expedites development of new probes and consequently promotes novel SPM applications.

  7. A Resonant Scanning Dipole-Antenna Probe for Enhanced Nanoscale Imaging

    NARCIS (Netherlands)

    Neumann, L.; van 't Oever, Jan Joannes Frederik; van Hulst, N.F.

    2013-01-01

    We present a scanning antenna probe that provides 35 nm optical hotspots with a 16-fold excitation enhancement. A resonant optical antenna, tuned to operation in the visible, is carved into the aluminum-coated scanning probe. The antenna resonances, field localization, excitation, and polarization

  8. The Use Of Scanning Probe Microscopy To Investigate Crystal-Fluid Interfaces

    International Nuclear Information System (INIS)

    Orme, C A; Giocondi, J L

    2007-01-01

    Over the past decade there has been a natural drive to extend the investigation of dynamic surfaces in fluid environments to higher resolution characterization tools. Various aspects of solution crystal growth have been directly visualized for the first time. These include island nucleation and growth using transmission electron microscopy and scanning tunneling microscopy; elemental step motion using scanning probe microscopy; and the time evolution of interfacial atomic structure using various diffraction techniques. In this lecture we will discuss the use of one such in situ method, scanning probe microscopy, as a means of measuring surface dynamics during crystal growth and dissolution. We will cover both practical aspects of imaging such as environmental control, fluid flow, and electrochemical manipulation, as well as the types of physical measurements that can be made. Measurements such as step motion, critical lengths, nucleation density, and step fluctuations, will be put in context of the information they provide about mechanistic processes at surfaces using examples from metal and mineral crystal growth

  9. Scanning tunneling microscopy III theory of STM and related scanning probe methods

    CERN Document Server

    Güntherodt, Hans-Joachim

    1993-01-01

    While the first two volumes on Scanning Tunneling Microscopy (STM) and its related scanning probe (SXM) methods have mainly concentrated on intro­ ducing the experimental techniques, as well as their various applications in different research fields, this third volume is exclusively devoted to the theory of STM and related SXM methods. As the experimental techniques including the reproducibility of the experimental results have advanced, more and more theorists have become attracted to focus on issues related to STM and SXM. The increasing effort in the development of theoretical concepts for STM/SXM has led to considerable improvements in understanding the contrast mechanism as well as the experimental conditions necessary to obtain reliable data. Therefore, this third volume on STM/SXM is not written by theorists for theorists, but rather for every scientist who is not satisfied by just obtaining real­ space images of surface structures by STM/SXM. After a brief introduction (Chap. 1), N. D. Lang first co...

  10. Circular mode: a new scanning probe microscopy method for investigating surface properties at constant and continuous scanning velocities.

    Science.gov (United States)

    Nasrallah, Hussein; Mazeran, Pierre-Emmanuel; Noël, Olivier

    2011-11-01

    In this paper, we introduce a novel scanning probe microscopy mode, called the circular mode, which offers expanded capabilities for surface investigations especially for measuring physical properties that require high scanning velocities and/or continuous displacement with no rest periods. To achieve these specific conditions, we have implemented a circular horizontal displacement of the probe relative to the sample plane. Thus the relative probe displacement follows a circular path rather than the conventional back and forth linear one. The circular mode offers advantages such as high and constant scanning velocities, the possibility to be combined with other classical operating modes, and a simpler calibration method of the actuators generating the relative displacement. As application examples of this mode, we report its ability to (1) investigate the influence of scanning velocity on adhesion forces, (2) measure easily and instantly the friction coefficient, and (3) generate wear tracks very rapidly for tribological investigations. © 2011 American Institute of Physics

  11. An Evanescent Field Optical Microscope. Scanning probe Microscopy

    NARCIS (Netherlands)

    van Hulst, N.F.; Segerink, Franciscus B.; Bölger, B.; Bölger, B.; Wickramasinghe, H. Kumar

    1991-01-01

    An Evanescent Field Optical Microscope (EFOM) is presented, which employs frustrated total internal reflection on a highly localized scale by means of a sharp dielectric tip. The coupling of the evanescent field to the sub-micrometer probe as a function of probe-sample distance, angle of incidence

  12. Study of Perylenetetracarboxylic Acid Dimethylimide Films by Cyclic Thermal Desorption and Scanning Probe Microscopy

    Science.gov (United States)

    Pochtennyi, A. E.; Lappo, A. N.; Il'yushonok, I. P.

    2018-02-01

    Some results of studying the direct-current (DC) conductivity of perylenetetracarboxylic acid dimethylimide films by cyclic oxygen thermal desorption are presented. The microscopic parameters of hopping electron transport over localized impurity and intrinsic states were determined. The bandgap width and the sign of major current carriers were determined by scanning probe microscopy methods (atomic force microscopy, scanning probe spectroscopy, and photoassisted Kelvin probe force microscopy). The possibility of the application of photoassisted scanning tunneling microscopy for the nanoscale phase analysis of photoconductive films is discussed.

  13. A fast scanning probe for DIII--D

    International Nuclear Information System (INIS)

    Watkins, J.G.; Salmonson, J.; Moyer, R.; Doerner, R.; Lehmer, R.; Schmitz, L.; Hill, D.N.

    1992-01-01

    A fast reciprocating probe has been developed for DIII--D which can penetrate the separatrix during H mode with up to 5 MW of NBI heating. The probe has been designed to carry various sensor tips into the scrape-off layer at a velocity of 3 m/s and dwell motionless for a programmed period of time. The driving force is provided by a pneumatic cylinder charged with helium to facilitate greater mass flow. The first series of experiments have been done using a Langmuir probe head with five graphite tips to measure radial profiles of n e , T e , φ f , n e , and φ f . The amplitude and phase of the fluctuating quantities are measured by using specially constructed vacuum compatible 5-kV coaxial transmission lines which allow us to extend the measurements into the MHz range. TTZ ceramic bearings and fast stroke bellows were also specially designed for the DIII--D probe. Initial measurements will be presented

  14. Probing Field Distributions on Waveguide Structures with an Atomic Force/Photon Scanning Tunneling Microscope

    NARCIS (Netherlands)

    Borgonjen, E.G.; Borgonjen, E.G.; Moers, M.H.P.; Moers, M.H.P.; Ruiter, A.G.T.; van Hulst, N.F.

    1995-01-01

    A 'stand-alone' Photon Scanning Tunneling Microscope combined with an Atomic force Microscope, using a micro-fabricated silicon-nitride probe, is applied to the imaging of field distribution in integrated optical ridge waveguides. The electric field on the waveguide is locally probed by coupling to

  15. Impedance measurements on Au microelectrodes using controlled atmosphere high temperature scanning probe microscope

    DEFF Research Database (Denmark)

    Wu, Yuehua; Hansen, Karin Vels; Jacobsen, Torben

    2011-01-01

    High temperature impedance measurements on Au microelectrodes deposited on polished yttria stabilized zirconia (YSZ) pellets were demonstrated using a newly designed controlled atmosphere high temperature scanning probe microscope (CAHT-SPM). Probes based on Pt0.8Ir0.2 were fabricated and employed...

  16. Theoretical analysis of a dual-probe scanning tunneling microscope setup on graphene

    DEFF Research Database (Denmark)

    Settnes, Mikkel; Power, Stephen R.; Petersen, Dirch Hjorth

    2014-01-01

    Experimental advances allow for the inclusion of multiple probes to measure the transport properties of a sample surface. We develop a theory of dual-probe scanning tunneling microscopy using a Green's function formalism, and apply it to graphene. Sampling the local conduction properties at finite...... to different scattering processes. We compute the conductance maps of graphene systems with different edge geometries or height fluctuations to determine the effects of nonideal graphene samples on dual-probe measurements. © 2014 American Physical Society....

  17. Evaluation of the nutrition screening tool for childhood cancer (SCAN).

    Science.gov (United States)

    Murphy, Alexia J; White, Melinda; Viani, Karina; Mosby, Terezie T

    2016-02-01

    Malnutrition is a serious concern for children with cancer and nutrition screening may offer a simple alternative to nutrition assessment for identifying children with cancer who are at risk of malnutrition. The present paper aimed to evaluate the nutrition screening tool for childhood cancer (SCAN). SCAN was developed after an extensive review of currently available tools and published screening recommendation, consideration of pediatric oncology nutrition guidelines, piloting questions, and consulting with members of International Pediatric Oncology Nutrition Group. In Study 1, the accuracy and validity of SCAN against pediatric subjective global nutrition assessment (pediatric SGNA) was determined. In Study 2, subjects were classified as 'at risk of malnutrition' and 'not at risk of malnutrition' according to SCAN and measures of height, weight, body mass index (BMI) and body composition were compared between the groups. The validation of SCAN against pediatric SGNA showed SCAN had 'excellent' accuracy (0.90, 95% CI 0.78-1.00; p malnutrition' and 'not at risk of malnutrition' according to SCAN, the 'at risk of malnutrition' group had significantly lower values for weight Z score (p = 0.001), BMI Z score (p = 0.001) and fat mass index (FMI) (p = 0.04), than the 'not at risk of malnutrition' group. This study shows that SCAN is a simple, quick and valid tool which can be used to identify children with cancer who are at risk of malnutrition. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  18. Aspects of scanning force microscope probes and their effects on dimensional measurement

    Energy Technology Data Exchange (ETDEWEB)

    Yacoot, Andrew [National Physical Laboratory, Teddington, Middlesex TW11 0LW (United Kingdom); Koenders, Ludger [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)], E-mail: andrew.yacoot@npl.co.uk

    2008-05-21

    The review will describe the various scanning probe microscopy tips and cantilevers used today for scanning force microscopy and magnetic force microscopy. Work undertaken to quantify the properties of cantilevers and tips, e.g. shape and radius, is reviewed together with an overview of the various tip-sample interactions that affect dimensional measurements. (topical review)

  19. TOPICAL REVIEW: Aspects of scanning force microscope probes and their effects on dimensional measurement

    Science.gov (United States)

    Yacoot, Andrew; Koenders, Ludger

    2008-05-01

    The review will describe the various scanning probe microscopy tips and cantilevers used today for scanning force microscopy and magnetic force microscopy. Work undertaken to quantify the properties of cantilevers and tips, e.g. shape and radius, is reviewed together with an overview of the various tip-sample interactions that affect dimensional measurements.

  20. Aspects of scanning force microscope probes and their effects on dimensional measurement

    International Nuclear Information System (INIS)

    Yacoot, Andrew; Koenders, Ludger

    2008-01-01

    The review will describe the various scanning probe microscopy tips and cantilevers used today for scanning force microscopy and magnetic force microscopy. Work undertaken to quantify the properties of cantilevers and tips, e.g. shape and radius, is reviewed together with an overview of the various tip-sample interactions that affect dimensional measurements. (topical review)

  1. Probing Nanoscale Electronic and Magnetic Interaction with Scanning Tunneling Spectroscopy

    DEFF Research Database (Denmark)

    Bork, Jakob

    tunneling microscope (STM). Especially at low temperatures the Kondo resonance is used to probe magnetic interaction with ferromagnetic islands and between two atoms. The latter showing a crossover between Kondo screened atoms and antiferromagnetically coupled atoms close to the quantum critical point....... This is related to research in correlated electron materials such as studies of phase transitions in heavy fermion compounds and magnetic interaction in spintronic research. The capping of cobalt islands on Cu(111) with silver is investigated with STM and photoemission spectroscopy. It is shown that at low...

  2. A carbon nanofibre scanning probe assembled using an electrothermal microgripper

    DEFF Research Database (Denmark)

    Carlson, Kenneth; Dyvelkov, Karin Nordström; Eicchorn, V.

    2007-01-01

    Functional devices can be directly assembled using microgrippers with an in situ electron microscope. Two simple and compact silicon microgripper designs are investigated here. These are operated by electrothermal actuation, and are used to transfer a catalytically grown multi-walled carbon...... nanofibre from a fixed position on a substrate to the tip of an atomic force microscope cantilever, inside a scanning electron microscope. Scanning of high aspect ratio trenches using the nanofibre supertip shows a significantly better performance than that with standard pyramidal silicon tips. Based...... on manipulation experiments as well as a simple analysis, we show that shear pulling (lateral movement of the gripper) is far more effective than tensile pulling (vertical movement of gripper) for the mechanical removal of carbon nanotubes from a substrate....

  3. A carbon nanofibre scanning probe assembled using an electrothermal microgripper

    International Nuclear Information System (INIS)

    Carlson, K; Andersen, K N; Eichorn, V; Petersen, D H; Moelhave, K; Bu, I Y Y; Teo, K B K; Milne, W I; Fatikow, S; Boeggild, P

    2007-01-01

    Functional devices can be directly assembled using microgrippers with an in situ electron microscope. Two simple and compact silicon microgripper designs are investigated here. These are operated by electrothermal actuation, and are used to transfer a catalytically grown multi-walled carbon nanofibre from a fixed position on a substrate to the tip of an atomic force microscope cantilever, inside a scanning electron microscope. Scanning of high aspect ratio trenches using the nanofibre supertip shows a significantly better performance than that with standard pyramidal silicon tips. Based on manipulation experiments as well as a simple analysis, we show that shear pulling (lateral movement of the gripper) is far more effective than tensile pulling (vertical movement of gripper) for the mechanical removal of carbon nanotubes from a substrate

  4. Synthesis and electroplating of high resolution insulated carbon nanotube scanning probes for imaging in liquid solutions.

    Science.gov (United States)

    Roberts, N A; Noh, J H; Lassiter, M G; Guo, S; Kalinin, S V; Rack, P D

    2012-04-13

    High resolution and isolated scanning probe microscopy (SPM) is in demand for continued development of energy storage and conversion systems involving chemical reactions at the nanoscale as well as an improved understanding of biological systems. Carbon nanotubes (CNTs) have large aspect ratios and, if leveraged properly, can be used to develop high resolution SPM probes. Isolation of SPM probes can be achieved by depositing a dielectric film and selectively etching at the apex of the probe. In this paper the fabrication of a high resolution and isolated SPM tip is demonstrated using electron beam induced etching of a dielectric film deposited onto an SPM tip with an attached CNT at the apex.

  5. Online correction of scanning probe microscopes with pixel accuracy

    DEFF Research Database (Denmark)

    Dirscherl, Kai

    2000-01-01

    of 10 nm and an opening angle of 30.0 °. Even atomic resolution can be achieved. The scan movement of the tip is not linear however. This is caused by the propelling device of the SPM for the scan motion - a piezoelectric ceramic. The two major non-linear responses o f the piezo to the applied control....... The algorithm typically contains 5 - 7 parameters which have to be calibrated manually. Still, non-linear errors remain in the order of 1-2%. One pixel in a 512x 512 image corresponds to 0.2% per direction. This goal of measurement accuracy i s reached with the algorithm developed in this thesis. Three...... different SPM are analyzed for their non-linearity. Two commercial tube sc anners are applied with a maximum scan range in x and y of 40.0 µm and 160.0 µm as well as one specially designed stack scanner with a maximum range of 5.0 µm. For the tube scanners, a 1-dimensional line pattern with a reference...

  6. A fast spatial scanning combination emissive and mach probe for edge plasma diagnosis

    International Nuclear Information System (INIS)

    Lehmer, R.D.; LaBombard, B.; Conn, R.W.

    1989-04-01

    A fast spatially scanning emissive and mach probe has been developed for the measurement of plasma profiles in the PISCES facility at UCLA. A pneumatic cylinder is used to drive a multiple tip probe along a 15cm stroke in less than 400msec, giving single shot profiles while limiting power deposition to the probe. A differentially pumped sliding O-ring seal allows the probe to be moved between shots to infer two and three dimensional profiles. The probe system has been used to investigate the plasma potential, density, and parallel mach number profiles of the presheath induced by a wall surface and scrape-off-layer profile modifications in biased limiter simulation experiments. Details of the hardware, data acquisition electronics, and tests of probe reliability are discussed. 30 refs., 24 figs

  7. Probing Individual Ice Nucleation Events with Environmental Scanning Electron Microscopy

    Science.gov (United States)

    Wang, Bingbing; China, Swarup; Knopf, Daniel; Gilles, Mary; Laskin, Alexander

    2016-04-01

    Heterogeneous ice nucleation is one of the processes of critical relevance to a range of topics in the fundamental and the applied science and technologies. Heterogeneous ice nucleation initiated by particles proceeds where microscopic properties of particle surfaces essentially control nucleation mechanisms. Ice nucleation in the atmosphere on particles governs the formation of ice and mixed phase clouds, which in turn influence the Earth's radiative budget and climate. Heterogeneous ice nucleation is still insufficiently understood and poses significant challenges in predictive understanding of climate change. We present a novel microscopy platform allowing observation of individual ice nucleation events at temperature range of 193-273 K and relative humidity relevant for ice formation in the atmospheric clouds. The approach utilizes a home built novel ice nucleation cell interfaced with Environmental Scanning Electron Microscope (IN-ESEM system). The IN-ESEM system is applied for direct observation of individual ice formation events, determining ice nucleation mechanisms, freezing temperatures, and relative humidity onsets. Reported microanalysis of the ice nucleating particles (INP) include elemental composition detected by the energy dispersed analysis of X-rays (EDX), and advanced speciation of the organic content in particles using scanning transmission x-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). The performance of the IN-ESEM system is validated through a set of experiments with kaolinite particles with known ice nucleation propensity. We demonstrate an application of the IN-ESEM system to identify and characterize individual INP within a complex mixture of ambient particles.

  8. The scanning probe microscopy study of thin polymer films

    International Nuclear Information System (INIS)

    Harron, H.R.

    1995-08-01

    Scanning Tunnelling Microscopy and Atomic Force Microscopy were used systematically to investigate the morphology, uniformity, coverage and structure of the thin films of several commercially important insulating polymers. Despite the poorly conducting nature of the polymer sample, detailed and convincing images of this class of materials were achieved by STM without the need to coat the samples with a conductive layer. The polymer regions of the sample were further investigated by the use of surface profiling with 'line scans'. The fluctuations of the amplitude therein enabled important film characteristics to be assessed. An environmental stage was designed for the STM to enable the effect of various vapour-sample interactions to be observed during the imaging process. Using the data from the environmental stage in addition to the surface profiling with line scans, an insight into the conduction mechanism and image interpretation was gained. Results suggest that the water content of the sample and its immediate surroundings is an important factor in achieving reliable STM images in air. The initial study culminated with the observation by STM alone of the plasticizer induced crystallization of uncoated PC thin films. The 'amorphous' PC films were observed before crystallization and small ordered regions in roughly the same proportion as that predicted by diffraction studies [Prietschk, 1959 and Schnell, 1964] were imaged. This has never been observed by a microscopy technique. Furthermore, images of the crystalline film contained elongated units that were attributed to the lamellae formations that form the basic building blocks of polymer spherulites. The study continued with the AFM imaging of the growth of crystalline entities in a PC film, without the need for harsh sample treatment or metal coating. A method of casting and crystallizing the films was developed such that the growth was predominantly in two dimensions and consequently ideal for observation by

  9. Heterobifunctional crosslinkers for tethering single ligand molecules to scanning probes

    International Nuclear Information System (INIS)

    Riener, Christian K.; Kienberger, Ferry; Hahn, Christoph D.; Buchinger, Gerhard M.; Egwim, Innocent O.C.; Haselgruebler, Thomas; Ebner, Andreas; Romanin, Christoph; Klampfl, Christian; Lackner, Bernd; Prinz, Heino; Blaas, Dieter; Hinterdorfer, Peter; Gruber, Hermann J.

    2003-01-01

    Single molecule recognition force microscopy (SMRFM) is a versatile atomic force microscopy (AFM) method to probe specific interactions of cognitive molecules on the single molecule level. It allows insights to be gained into interaction potentials and kinetic barriers and is capable of mapping interaction sites with nm positional accuracy. These applications require a ligand to be attached to the AFM tip, preferably by a distensible poly(ethylene glycol) (PEG) chain between the measuring tip and the ligand molecule. The PEG chain greatly facilitates specific binding of the ligand to immobile receptor sites on the sample surface. The present study contributes to tip-PEG-ligand tethering in three ways: (i) a convenient synthetic route was found to prepare NH 2 -PEG-COOH which is the key intermediate for long heterobifunctional crosslinkers; (ii) a variety of heterobifunctional PEG derivatives for tip-PEG-ligand linking were prepared from NH 2 -PEG-COOH; (iii) in particular, a new PEG crosslinker with one thiol-reactive end and one terminal nitrilotriacetic acid (NTA) group was synthesized and successfully used to tether His 6 -tagged protein molecules to AFM tips via noncovalent NTA-Ni 2+ -His 6 bridges. The new crosslinker was applied to link a recombinant His 6 -tagged fragment of the very-low density lipoprotein receptor to the AFM tip whereupon specific docking to the capsid of human rhinovirus particles was observed by force microscopy. In a parallel study, the specific interaction of the small GTPase Ran with the nuclear import receptor importin β1 was studied in detail by SMRFM, using the new crosslinker to link His 6 -tagged Ran to the measuring tip [Nat. Struct. Biol. (2003), 10, 553-557

  10. Solid-state electrochemistry on the nanometer and atomic scales: the scanning probe microscopy approach

    Science.gov (United States)

    Strelcov, Evgheni; Yang, Sang Mo; Jesse, Stephen; Balke, Nina; Vasudevan, Rama K.; Kalinin, Sergei V.

    2016-01-01

    Energy technologies of the 21st century require understanding and precise control over ion transport and electrochemistry at all length scales – from single atoms to macroscopic devices. This short review provides a summary of recent works dedicated to methods of advanced scanning probe microscopy for probing electrochemical transformations in solids at the meso-, nano- and atomic scales. Discussion presents advantages and limitations of several techniques and a wealth of examples highlighting peculiarities of nanoscale electrochemistry. PMID:27146961

  11. A combined scanning tunneling microscope-atomic layer deposition tool.

    Science.gov (United States)

    Mack, James F; Van Stockum, Philip B; Iwadate, Hitoshi; Prinz, Fritz B

    2011-12-01

    We have built a combined scanning tunneling microscope-atomic layer deposition (STM-ALD) tool that performs in situ imaging of deposition. It operates from room temperature up to 200 °C, and at pressures from 1 × 10(-6) Torr to 1 × 10(-2) Torr. The STM-ALD system has a complete passive vibration isolation system that counteracts both seismic and acoustic excitations. The instrument can be used as an observation tool to monitor the initial growth phases of ALD in situ, as well as a nanofabrication tool by applying an electric field with the tip to laterally pattern deposition. In this paper, we describe the design of the tool and demonstrate its capability for atomic resolution STM imaging, atomic layer deposition, and the combination of the two techniques for in situ characterization of deposition.

  12. Final report: Mapping Interactions in Hybrid Systems with Active Scanning Probes

    Energy Technology Data Exchange (ETDEWEB)

    Berezovsky, Jesse [Case Western Reserve Univ., Cleveland, OH (United States)

    2017-09-29

    This project aimed to study and map interactions between components of hybrid nanodevices using a novel scanning probe approach. To enable this work, we initially constructed a flexible experimental apparatus allowing for simultaneous scanning probe and confocal optical microscopy measurements. This setup was first used for all-optical measurements of nanostructures, with the focus then shifting to hybrid devices in which single coherent electron spins are coupled to micron-scale ferromagnetic elements, which may prove useful for addressing single spins, enhanced sensing, or spin-wave-mediated coupling of spins for quantum information applications. A significant breakthrough was the realization that it is not necessary to fabricate a magnetic structure on a scanning probe – instead a ferromagnetic vortex core can act as an integrated, solid state, scanning probe. The core of the vortex produces a very strong, localized fringe field which can be used analogously to an MFM tip. Unlike a traditional MFM tip, however, the vortex core is scanned within an integrated device (eliminating drift), and can be moved on vastly faster timescales. This approach allows the detailed investigation of interactions between single spins and complex driven ferromagnetic dynamics.

  13. True Tapping Mode Scanning Near-Field Optical Microscopy with Bent Glass Fiber Probes.

    Science.gov (United States)

    Smirnov, A; Yasinskii, V M; Filimonenko, D S; Rostova, E; Dietler, G; Sekatskii, S K

    2018-01-01

    In scanning near-field optical microscopy, the most popular probes are made of sharpened glass fiber attached to a quartz tuning fork (TF) and exploiting the shear force-based feedback. The use of tapping mode feedback could be preferable. Such an approach can be realized, for example, using bent fiber probes. Detailed analysis of fiber vibration modes shows that realization of truly tapping mode of the probe dithering requires an extreme caution. In case of using the second resonance mode, probes vibrate mostly in shear force mode unless the bending radius is rather small (ca. 0.3 mm) and the probe's tip is short. Otherwise, the shear force character of the dithering persists. Probes having these characteristics were prepared by irradiation of a tapered etched glass fiber with a CW CO 2 laser. These probes were attached to the TF in double resonance conditions which enables achieving significant quality factor (4000-6000) of the TF + probe system (Cherkun et al., 2006). We also show that, to achieve a truly tapping character, dithering, short, and not exceeding 3 mm lengths of a freestanding part of bent fiber probe beam should also be used in the case of nonresonant excitation.

  14. Improve performance of scanning probe microscopy by balancing tuning fork prongs

    International Nuclear Information System (INIS)

    Ng, Boon Ping; Zhang Ying; Wei Kok, Shaw; Chai Soh, Yeng

    2009-01-01

    This paper presents an approach for improving the Q-factor of tuning fork probe used in scanning probe microscopes. The improvement is achieved by balancing the fork prongs with extra mass attachment. An analytical model is proposed to characterize the Q-factor of a tuning fork probe with respect to the attachment of extra mass on the tuning fork prongs, and based on the model, the Q-factors of the unbalanced and balanced tuning fork probes are derived and compared. Experimental results showed that the model fits well the experimental data and the approach can improve the Q-factor by more than a factor of three. The effectiveness of the approach is further demonstrated by applying the balanced probe on an atomic force microscope to obtain improved topographic images.

  15. Mapping the antioxidant activity of apple peels with soft probe scanning electrochemical microscopy

    OpenAIRE

    Lin, Tzu-En; Lesch, Andreas; Li, Chi-Lin; Girault, Hubert

    2017-01-01

    We present a non-invasive electrochemical strategy for mapping the antioxidant (AO) activity of apple peels, which counterbalances oxidative stress caused by various external effectors. Soft carbon microelectrodes were used for soft probe scanning electrochemical microscopy (SECM) enabling the gentle and scratch-free in contact mode scanning of the rough and delicate apple peels in an electrolyte solution. The SECM feedback mode was applied using ferrocene methanol (FcMeOH) as redox mediator ...

  16. True Tapping Mode Scanning Near-Field Optical Microscopy with Bent Glass Fiber Probes

    Directory of Open Access Journals (Sweden)

    A. Smirnov

    2018-01-01

    Full Text Available In scanning near-field optical microscopy, the most popular probes are made of sharpened glass fiber attached to a quartz tuning fork (TF and exploiting the shear force-based feedback. The use of tapping mode feedback could be preferable. Such an approach can be realized, for example, using bent fiber probes. Detailed analysis of fiber vibration modes shows that realization of truly tapping mode of the probe dithering requires an extreme caution. In case of using the second resonance mode, probes vibrate mostly in shear force mode unless the bending radius is rather small (ca. 0.3 mm and the probe’s tip is short. Otherwise, the shear force character of the dithering persists. Probes having these characteristics were prepared by irradiation of a tapered etched glass fiber with a CW CO2 laser. These probes were attached to the TF in double resonance conditions which enables achieving significant quality factor (4000–6000 of the TF + probe system (Cherkun et al., 2006. We also show that, to achieve a truly tapping character, dithering, short, and not exceeding 3 mm lengths of a freestanding part of bent fiber probe beam should also be used in the case of nonresonant excitation.

  17. Experimental Route to Scanning Probe Hot Electron Nanoscopy (HENs) Applied to 2D Material

    KAUST Repository

    Giugni, Andrea; Torre, Bruno; Allione, Marco; Das, Gobind; Wang, Zhenwei; He, Xin; Alshareef, Husam N.; Di Fabrizio, Enzo M.

    2017-01-01

    for applications in electronics: 2D MoS2 single crystal and a p-type SnO layer. Results are supported by complementary scanning Kelvin probe microscopy, traditional conductive AFM, and Raman measurements. New features highlighted by HEN technique reveal details

  18. Multiterminal semiconductor/ferromagnet probes for spin-filter scanning tunneling microscopy

    NARCIS (Netherlands)

    Vera Marun, I.J.; Jansen, R.

    2009-01-01

    We describe the fabrication of multiterminal semiconductor/ferromagnet probes for a new technique to study magnetic nanostructures: spin-filter scanning tunneling microscopy. We describe the principle of the technique, which is based on spin-polarized tunneling and subsequent analysis of the spin

  19. Supramolecular chemistry at the liquid/solid interface probed by scanning tunnelling microscopy

    NARCIS (Netherlands)

    Feyter, S. De; Uji-i, H.; Mamdouh, W.; Miura, A.; Zhang, J.; Jonkheijm, P.; Schenning, A.P.H.J.; Meijer, E.W.; Chen, Z.; Wurthner, F.; Schuurmans, N.; Esch, J. van; Feringa, B.L.; Dulcey, A.E.; Percec, V.; Schryver, F.C. De

    2006-01-01

    The liquid/solid interface provides an ideal environment to investigate self-assembly phenomena, and scanning tunnelling microscopy (STM) is one of the preferred methodologies to probe the structure and the properties of physisorbed monolayers on the nanoscale. Physisorbed monolayers are of

  20. A robust method for processing scanning probe microscopy images and determining nanoobject position and dimensions

    NARCIS (Netherlands)

    Silly, F.

    2009-01-01

    P>Processing of scanning probe microscopy (SPM) images is essential to explore nanoscale phenomena. Image processing and pattern recognition techniques are developed to improve the accuracy and consistency of nanoobject and surface characterization. We present a robust and versatile method to

  1. Nanoscale electrical property studies of individual GeSi quantum rings by conductive scanning probe microscopy.

    Science.gov (United States)

    Lv, Yi; Cui, Jian; Jiang, Zuimin M; Yang, Xinju

    2012-11-29

    The nanoscale electrical properties of individual self-assembled GeSi quantum rings (QRs) were studied by scanning probe microscopy-based techniques. The surface potential distributions of individual GeSi QRs are obtained by scanning Kelvin microscopy (SKM). Ring-shaped work function distributions are observed, presenting that the QRs' rim has a larger work function than the QRs' central hole. By combining the SKM results with those obtained by conductive atomic force microscopy and scanning capacitance microscopy, the correlations between the surface potential, conductance, and carrier density distributions are revealed, and a possible interpretation for the QRs' conductance distributions is suggested.

  2. Field programmable gate array based reconfigurable scanning probe/optical microscope.

    Science.gov (United States)

    Nowak, Derek B; Lawrence, A J; Dzegede, Zechariah K; Hiester, Justin C; Kim, Cliff; Sánchez, Erik J

    2011-10-01

    The increasing popularity of nanometrology and nanospectroscopy has pushed researchers to develop complex new analytical systems. This paper describes the development of a platform on which to build a microscopy tool that will allow for flexibility of customization to suit research needs. The novelty of the described system lies in its versatility of capabilities. So far, one version of this microscope has allowed for successful near-field and far-field fluorescence imaging with single molecule detection sensitivity. This system is easily adapted for reflection, polarization (Kerr magneto-optical (MO)), Raman, super-resolution techniques, and other novel scanning probe imaging and spectroscopic designs. While collecting a variety of forms of optical images, the system can simultaneously monitor topographic information of a sample with an integrated tuning fork based shear force system. The instrument has the ability to image at room temperature and atmospheric pressure or under liquid. The core of the design is a field programmable gate array (FPGA) data acquisition card and a single, low cost computer to control the microscope with analog control circuitry using off-the-shelf available components. A detailed description of electronics, mechanical requirements, and software algorithms as well as examples of some different forms of the microscope developed so far are discussed.

  3. Autonomous Scanning Probe Microscopy in Situ Tip Conditioning through Machine Learning.

    Science.gov (United States)

    Rashidi, Mohammad; Wolkow, Robert A

    2018-05-23

    Atomic-scale characterization and manipulation with scanning probe microscopy rely upon the use of an atomically sharp probe. Here we present automated methods based on machine learning to automatically detect and recondition the quality of the probe of a scanning tunneling microscope. As a model system, we employ these techniques on the technologically relevant hydrogen-terminated silicon surface, training the network to recognize abnormalities in the appearance of surface dangling bonds. Of the machine learning methods tested, a convolutional neural network yielded the greatest accuracy, achieving a positive identification of degraded tips in 97% of the test cases. By using multiple points of comparison and majority voting, the accuracy of the method is improved beyond 99%.

  4. Near-field scanning optical microscopy using polymethylmethacrylate optical fiber probes

    International Nuclear Information System (INIS)

    Chibani, H.; Dukenbayev, K.; Mensi, M.; Sekatskii, S.K.; Dietler, G.

    2010-01-01

    We report the first use of polymethylmethacrylate (PMMA) optical fiber-made probes for scanning near-field optical microscopy (SNOM). The sharp tips were prepared by chemical etching of the fibers in ethyl acetate, and the probes were prepared by proper gluing of sharpened fibers onto the tuning fork in the conditions of the double resonance (working frequency of a tuning fork coincides with the resonance frequency of dithering of the free-standing part of the fiber) reported earlier for the case of glass fibers. Quality factors of the probes in the range 2000-6000 were obtained, which enables the realization of an excellent topographical resolution including state-of-art imaging of single DNA molecules. Near-field optical performance of the microscope is illustrated by the Photon Scanning Tunneling Microscope images of fluorescent beads with a diameter of 100 nm. The preparation of these plastic fiber probes proved to be easy, needs no hazardous material and/or procedures, and typical lifetime of a probe essentially exceeds that characteristic for the glass fiber probe.

  5. Electromechanical response of amorphous LaAlO{sub 3} thin film probed by scanning probe microscopies

    Energy Technology Data Exchange (ETDEWEB)

    Borowiak, Alexis S.; Baboux, Nicolas; Albertini, David; Gautier, Brice, E-mail: brice.gautier@insa-lyon.fr [Institut des nanotechnologies de Lyon (INL), Institut National des Sciences Appliquées de Lyon, Université de Lyon, UMR CNRS 5270, 7 Avenue Capelle, F-69621 Villeurbanne Cedex (France); Vilquin, Bertrand; Saint Girons, Guillaume; Pelloquin, Sylvain [Institut des nanotechnologies de Lyon (INL), Ecole Centrale de Lyon, Université de Lyon, UMR CNRS 5270, 36 Avenue Guy de Collongues, F-69134 Ecully Cedex (France)

    2014-07-07

    The electromechanical response of a 3 nm thick amorphous LaAlO{sub 3} layer obtained by molecular beam epitaxy has been studied using scanning probe microscopies. Although this kind of sample is not ferroelectric due to its amorphous nature, the resulting images are identical to what is generally obtained on truly ferroelectric samples probed by piezoresponse force microscopy: domains of apparently opposite polarisation are detected, and perfect, square shaped hysteresis loops are recorded. Moreover, written patterns are stable within 72 h. We discuss in the general case the possible origins of this behaviour in terms of charge injection, ionic conduction and motion of oxygen vacancies. In the case presented in this paper, since the writing process has been conducted with applied voltages lower than the injection threshold measured by conductive atomic force Microscopy, allowing to withdraw the hypothesis of charge injection in the sample, we propose that a bistable distribution of oxygen vacancies is responsible for this contrast.

  6. A scanning contact probe for a micro-coordinate measuring machine (CMM)

    International Nuclear Information System (INIS)

    Fan, Kuang-Chao; Cheng, Fang; Wang, Weili; Chen, Yejin; Lin, Jia-You

    2010-01-01

    A new high precision contact scanning probe able to measure miniature components on a micro/nano-coordinate measuring machine (CMM) is proposed. This contact probe is composed of a fiber stylus with a ball tip, a floating plate and focus sensors. The stylus is attached to a floating plate, which is connected to the probe housing via four elastic wires. When the probe tip is touched and then deflected by the workpiece, the wires experience elastic deformations and the four mirrors mounted on the plate will be displaced. These displacements can be detected by four corresponding laser focus probes. To calibrate this touch trigger probe, a double-trigger method is developed for a high-speed approach and a low-speed touch. Experimental results show that the probe has a symmetric contact property in the horizontal XY plane. The contact force is found to be about 109 µN. The standard deviation of the unidirectional touch is less than 10 nm and the pre-travel distance is around 10 nm with a standard deviation of less than 3 nm

  7. A scanning Hall probe microscope for high resolution magnetic imaging down to 300 mK

    International Nuclear Information System (INIS)

    Khotkevych, V. V.; Bending, S. J.; Milosevic, M. V.

    2008-01-01

    We present the design, construction, and performance of a low-temperature scanning Hall probe microscope with submicron lateral resolution and a large scanning range. The detachable microscope head is mounted on the cold flange of a commercial 3 He-refrigerator (Oxford Instruments, Heliox VT-50) and operates between room temperature and 300 mK. It is fitted with a three-axis slip-stick nanopositioner that enables precise in situ adjustment of the probe location within a 6x6x7 mm 3 space. The local magnetic induction at the sample surface is mapped with an easily changeable microfabricated Hall probe [typically GsAs/AlGaAs or AlGaAs/InGaAs/GaAs Hall sensors with integrated scanning tunnel microscopy (STM) tunneling tips] and can achieve minimum detectable fields ≥10 mG/Hz 1/2 . The Hall probe is brought into very close proximity to the sample surface by sensing and controlling tunnel currents at the integrated STM tip. The instrument is capable of simultaneous tunneling and Hall signal acquisition in surface-tracking mode. We illustrate the potential of the system with images of superconducting vortices at the surface of a Nb thin film down to 372 mK, and also of labyrinth magnetic-domain patterns of an yttrium iron garnet film captured at room temperature.

  8. Micro-four-point probes in a UHV scanning electron microscope for in-situ surface-conductivity measurements

    DEFF Research Database (Denmark)

    Shiraki, I.; Nagao, T.; Hasegawa, S.

    2000-01-01

    For in-situ measurements of surface conductivity in ultrahigh vacuum (UHV), we have installed micro-four-point probes (probe spacings down to 4 mum) in a UHV scanning electron microscope (SEM) combined with scanning reflection-high-energy electron diffraction (RHEED). With the aid of piezoactuators...

  9. Study of sapphire probe tip wear when scanning on different materials

    International Nuclear Information System (INIS)

    Nicolet, Anaïs; Küng, Alain; Meli, Felix

    2012-01-01

    The accuracy of today's coordinate measuring machines (CMM) has reached a level at which exact knowledge of each component is required. The role of the probe tip is particularly crucial as it is in contact with the sample surface. Understanding how the probe tip wears off will help to narrow the measurement errors. In this work, wear of a sapphire sphere was studied for different scanning conditions and with different sample materials. Wear depth on the probe was investigated using an automated process in situ on the METAS micro-CMM and completed by measurements with an atomic force microscope. We often found a linear dependence between the wear depth and the scan length ranging from 0.5 to 9 nm m −1 , due to variations in scan speed, contact force or sample material. In the case of steel, the wear rate is proportional to the scan speed, while for aluminum several processes seem to interact. A large amount of debris was visible after the tests. Except for aluminum, wear was visible only on the sphere and not on the sample. Sapphire/steel is the worst combination in terms of wear, whereas the combination sapphire/ceramic exhibits almost no wear. (paper)

  10. A quadruple-scanning-probe force microscope for electrical property measurements of microscopic materials

    International Nuclear Information System (INIS)

    Higuchi, Seiji; Kubo, Osamu; Kuramochi, Hiromi; Aono, Masakazu; Nakayama, Tomonobu

    2011-01-01

    Four-terminal electrical measurement is realized on a microscopic structure in air, without a lithographic process, using a home-built quadruple-scanning-probe force microscope (QSPFM). The QSPFM has four probes whose positions are individually controlled by obtaining images of a sample in the manner of atomic force microscopy (AFM), and uses the probes as contacting electrodes for electrical measurements. A specially arranged tuning fork probe (TFP) is used as a self-detection force sensor to operate each probe in a frequency modulation AFM mode, resulting in simultaneous imaging of the same microscopic feature on an insulator using the four TFPs. Four-terminal electrical measurement is then demonstrated in air by placing each probe electrode in contact with a graphene flake exfoliated on a silicon dioxide film, and the sheet resistance of the flake is measured by the van der Pauw method. The present work shows that the QSPFM has the potential to measure the intrinsic electrical properties of a wide range of microscopic materials in situ without electrode fabrication.

  11. Observation of quantized vortices by cryocooler-based scanning Hall probe microscope

    Energy Technology Data Exchange (ETDEWEB)

    Tokunaga, Y.; Konishi, Y.; Tokunaga, M.; Tamegai, T

    2004-10-01

    We have developed a scanning Hall probe microscope (SHPM) system utilizing closed-cycle cryocooler. The Hall probe used in this system is fabricated from a GaAs/GaAlAs two-dimensional electron gas. A stepping-motor-driven XYZ translator is used with a resolution better than 0.1 {mu}m and maximum scan range of 20 x 20 mm{sup 2}. The spatial resolution of the system is about 5 {mu}m and magnetic resolution is about 100 mG. By using this system, we have successfully resolved the quantized vortices on the cleaved surface of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+y} single crystal.

  12. Toward the Atomic-Level Mass Analysis of Biomolecules by the Scanning Atom Probe.

    Science.gov (United States)

    Nishikawa, Osamu; Taniguchi, Masahiro

    2017-04-01

    In 1994, a new type of atom probe instrument, named the scanning atom probe (SAP), was proposed. The unique feature of the SAP is the introduction of a small extraction electrode, which scans over a specimen surface and confines the high field, required for field evaporation of surface atoms in a small space, between the specimen and the electrode. Thus, the SAP does not require a sharp specimen tip. This indicates that the SAP can mass analyze the specimens which are difficult to form in a sharp tip, such as organic materials and biomolecules. Clean single wall carbon nanotubes (CNT), made by high-pressure carbon monoxide process are found to be the best substrates for biomolecules. Various amino acids and dipeptide biomolecules were successfully mass analyzed, revealing characteristic clusters formed by strongly bound atoms in the specimens. The mass analysis indicates that SAP analysis of biomolecules is not only qualitative, but also quantitative.

  13. Ultrasound probe and needle-guide calibration for robotic ultrasound scanning and needle targeting.

    Science.gov (United States)

    Kim, Chunwoo; Chang, Doyoung; Petrisor, Doru; Chirikjian, Gregory; Han, Misop; Stoianovici, Dan

    2013-06-01

    Image-to-robot registration is a typical step for robotic image-guided interventions. If the imaging device uses a portable imaging probe that is held by a robot, this registration is constant and has been commonly named probe calibration. The same applies to probes tracked by a position measurement device. We report a calibration method for 2-D ultrasound probes using robotic manipulation and a planar calibration rig. Moreover, a needle guide that is attached to the probe is also calibrated for ultrasound-guided needle targeting. The method is applied to a transrectal ultrasound (TRUS) probe for robot-assisted prostate biopsy. Validation experiments include TRUS-guided needle targeting accuracy tests. This paper outlines the entire process from the calibration to image-guided targeting. Freehand TRUS-guided prostate biopsy is the primary method of diagnosing prostate cancer, with over 1.2 million procedures performed annually in the U.S. alone. However, freehand biopsy is a highly challenging procedure with subjective quality control. As such, biopsy devices are emerging to assist the physician. Here, we present a method that uses robotic TRUS manipulation. A 2-D TRUS probe is supported by a 4-degree-of-freedom robot. The robot performs ultrasound scanning, enabling 3-D reconstructions. Based on the images, the robot orients a needle guide on target for biopsy. The biopsy is acquired manually through the guide. In vitro tests showed that the 3-D images were geometrically accurate, and an image-based needle targeting accuracy was 1.55 mm. These validate the probe calibration presented and the overall robotic system for needle targeting. Targeting accuracy is sufficient for targeting small, clinically significant prostatic cancer lesions, but actual in vivo targeting will include additional error components that will have to be determined.

  14. Theoretical analysis of a dual-probe scanning tunneling microscope setup on graphene.

    Science.gov (United States)

    Settnes, Mikkel; Power, Stephen R; Petersen, Dirch H; Jauho, Antti-Pekka

    2014-03-07

    Experimental advances allow for the inclusion of multiple probes to measure the transport properties of a sample surface. We develop a theory of dual-probe scanning tunneling microscopy using a Green's function formalism, and apply it to graphene. Sampling the local conduction properties at finite length scales yields real space conductance maps which show anisotropy for pristine graphene systems and quantum interference effects in the presence of isolated impurities. Spectral signatures in the Fourier transforms of real space conductance maps include characteristics that can be related to different scattering processes. We compute the conductance maps of graphene systems with different edge geometries or height fluctuations to determine the effects of nonideal graphene samples on dual-probe measurements.

  15. Characterization of structural and electrostatic complexity in pentacene thin films by scanning probe microscopy

    Science.gov (United States)

    Puntambekar, Kanan Prakash

    The advancement of organic electronics for applications in solar energy conversion, printed circuitry, displays, and solid-state lighting depends upon optimization of structure and properties for a variety of organic semiconductor interfaces. Organic semiconductor/insulator (O/I) and organic-metal (O/M) interfaces, in particular, are critical to the operation of organic thin film transistors (OTFTs) currently being developed for printed flexible electronics. Scanning probe microscopy (SPM) is a powerful tool to isolate and characterize the bottlenecks to charge transport at these interfaces. This thesis establishes a direct correlation between the structural disorder and electrical complexity at these interfaces, using various SPM based methods and discusses the implications of such complexity on device performance. To examine the O/M interfaces, surface potentials of operating pentacene TFTs with two different contact geometries (bottom or top) were mapped by Kelvin probe force microscopy (KFM). The surface potential distribution was used to isolate the potential drops at the source and drain contacts. Simultaneously obtained topography and surface potential maps elucidated the correlation between the morphology and contact resistance at the O/M interface; the bottom contact TFTs were observed to be contact limited at large gate voltages, while the top contact TFTs were not contact limited. A direct correlation between structural defects and electric potential variations at the pentacene and silicon dioxide, a common insulator, is demonstrated. Lateral force microscopy (LFM) generates striking images of the polycrystalline microstructure of a monolayer thick pentacene film, allowing clear visualization of the grain boundary network. Further more, surface potential wells localized at the grain boundaries were observed by KFM, suggesting that the grain boundaries may serve as charge carrier (hole) traps. Line dislocations were also revealed in the second monolayer

  16. Self-mixing laser diode included in scanning microwave microscope to the control of probe nanodisplacement

    Science.gov (United States)

    Usanov, D. A.; Skripal, A. V.; Astakhov, E. I.; Dobdin, S. Y.

    2018-04-01

    The possibilities of self-mixing interferometry for measuring nanodisplacement of a probe included in a near-field scanning microwave microscope have been considered. The features of the formation of a laser interference signal at current modulation of the wavelength of laser radiation have been investigated. Experimental responses of a semiconductor laser system included in scanning microwave microscope to control nanodisplacement of the probe have been demonstrated.To register the nanodisplacement of the probe, it is proposed to use the method of determining the stationary phase of a laser interference signal by low-frequency spectrum of a semiconductor laser. The change of the amplitudes of the spectral components in the spectrum of the interference signal due to creation of the standing wave in the external resonator of the laser self-mixing system has been shown. The form of the interference signal at current modulation of the radiation wavelength was experimentally obtained when the probe moves with a step of 80 nm. The results of measuring nanodisplacements of an electromagnetic translator STANDA 8MVT40-13 have been demonstrated. Deviation of the nanodisplacement of the proposed method does not exceed 15%.

  17. Reciprocity theory of apertureless scanning near-field optical microscopy with point-dipole probes.

    Science.gov (United States)

    Esslinger, Moritz; Vogelgesang, Ralf

    2012-09-25

    Near-field microscopy offers the opportunity to reveal optical contrast at deep subwavelength scales. In scanning near-field optical microscopy (SNOM), the diffraction limit is overcome by a nanoscopic probe in close proximity to the sample. The interaction of the probe with the sample fields necessarily perturbs the bare sample response, and a critical issue is the interpretation of recorded signals. For a few specific SNOM configurations, individual descriptions have been modeled, but a general and intuitive framework is still lacking. Here, we give an exact formulation of the measurable signals in SNOM which is easily applicable to experimental configurations. Our results are in close analogy with the description Tersoff and Hamann have derived for the tunneling currents in scanning tunneling microscopy. For point-like scattering probe tips, such as used in apertureless SNOM, the theory simplifies dramatically to a single scalar relation. We find that the measured signal is directly proportional to the field of the coupled tip-sample system at the position of the tip. For weakly interacting probes, the model thus verifies the empirical findings that the recorded signal is proportional to the unperturbed field of the bare sample. In the more general case, it provides guidance to an intuitive and faithful interpretation of recorded images, facilitating the characterization of tip-related distortions and the evaluation of novel SNOM configurations, both for aperture-based and apertureless SNOM.

  18. Large-scale high-resolution scanning Hall probe microscope used for MgB2 filament characterization

    International Nuclear Information System (INIS)

    Cambel, V; Fedor, J; Gregusova, D; Kovac, P; Husek, I

    2005-01-01

    The scanning Hall probe microscope (SHPM) is an important imaging tool used for detailed studies of superconductors in basic science as well as in the industrial sector. It can be used for the studies of losses, current distribution, and effects at grain boundaries. However, only a few SHPMs for magnetic field imaging at temperatures below 77 K have been proposed up to now, most of them designed for small-area (∼10x10 μm 2 ) scanning. We present a large-scale low-temperature SHPM developed for imaging the entire magnetic field in close proximity to magnetic and superconducting samples at 4.2-300 K. The microscope combines a large scanned area and high spatial and magnetic field resolution. The instrument is designed as an insert of standard helium flowing cryostats. The Hall sensor scans an area up to 7 x 25 mm 2 in the whole temperature interval with a spatial resolution better than 5 μm. The presented system is used for the study of ex situ prepared MgB 2 filament. We show that external magnetic field induces local supercurrents in the MgB 2 , from which the critical current can be estimated. Moreover, it indicates the microstructure and space homogeneity of the superconductor

  19. Ultrafast dissociation: An unexpected tool for probing molecular dynamics

    International Nuclear Information System (INIS)

    Morin, Paul; Miron, Catalin

    2012-01-01

    Highlights: ► Ultrafast dissociation has been investigated by means of XPS and mass spectrometry. ► The interplay between electron relaxation and molecular dynamics is evidenced. ► Extension toward polyatomics, clusters, adsorbed molecules is considered. ► Quantum effects (spectral hole, angular effects) evidence the molecular field anisotropy. -- Abstract: Ultrafast dissociation following core–shell excitation into an antibonding orbital led to the early observation in HBr of atomic Auger lines associated to the decay of dissociated excited atoms. The purpose of this article is to review the very large variety of systems where such a situation has been encountered, extending from simple diatomic molecules toward more complex systems like polyatomics, clusters, or adsorbed molecules. Interestingly, this phenomenon has revealed an extremely rich and powerful tool for probing nuclear dynamics and its subtle interplay with electron relaxation occurring on a comparable time scale. Consequently this review covers a surprisingly large period, starting in 1986 and still ongoing.

  20. Development of X-ray excitable luminescent probes for scanning X-ray microscopy

    International Nuclear Information System (INIS)

    Moronne, M.M.

    1999-01-01

    Transmission soft X-ray microscopy is now capable of achieving resolutions that are typically 5 times better than the best-visible light microscopes. With expected improvements in zone plate optics, an additional factor of two may be realized within the next few years. Despite the high resolution now available with X-ray microscopes and the high X-ray contrast provided by biological molecules in the soft X-ray region (λ=2-5 nm), molecular probes for localizing specific biological targets have been lacking. To circumvent this problem, X-ray excitable molecular probes are needed that can target unique biological features. In this paper we report our initial results on the development of lanthanide-based fluorescent probes for biological labeling. Using scanning luminescence X-ray microscopy (SLXM, Jacobsen et al., J. Microscopy 172 (1993) 121-129), we show that lanthanide organo-polychelate complexes are sufficiently bright and radiation resistant to be the basis of a new class of X-ray excitable molecular probes capable of providing at least a fivefold improvement in resolution over visible light microscopy. Lanthanide probes, able to bind 80-100 metal ions per molecule, were found to give strong luminescent signals with X-ray doses exceeding 10 8 Gy, and were used to label actin stress fibers and in vitro preparations of polymerized tubulin. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  1. MEMS-based non-rotatory circumferential scanning optical probe for endoscopic optical coherence tomography

    Science.gov (United States)

    Xu, Yingshun; Singh, Janak; Siang, Teo Hui; Ramakrishna, Kotlanka; Premchandran, C. S.; Sheng, Chen Wei; Kuan, Chuah Tong; Chen, Nanguang; Olivo, Malini C.; Sheppard, Colin J. R.

    2007-07-01

    In this paper, we present a non-rotatory circumferential scanning optical probe integrated with a MEMS scanner for in vivo endoscopic optical coherence tomography (OCT). OCT is an emerging optical imaging technique that allows high resolution cross-sectional imaging of tissue microstructure. To extend its usage to endoscopic applications, a miniaturized optical probe based on Microelectromechanical Systems (MEMS) fabrication techniques is currently desired. A 3D electrothermally actuated micromirror realized using micromachining single crystal silicon (SCS) process highlights its very large angular deflection, about 45 degree, with low driving voltage for safety consideration. The micromirror is integrated with a GRIN lens into a waterproof package which is compatible with requirements for minimally invasive endoscopic procedures. To implement circumferential scanning substantially for diagnosis on certain pathological conditions, such as Barret's esophagus, the micromirror is mounted on 90 degree to optical axis of GRIN lens. 4 Bimorph actuators that are connected to the mirror on one end via supporting beams and springs are selected in this micromirror design. When actuators of the micromirror are driven by 4 channels of sinusoidal waveforms with 90 degree phase differences, beam focused by a GRIN is redirected out of the endoscope by 45 degree tilting mirror plate and achieve circumferential scanning pattern. This novel driving method making full use of very large angular deflection capability of our micromirror is totally different from previously developed or developing micromotor-like rotatory MEMS device for circumferential scanning.

  2. Transfer doping of single isolated nanodiamonds, studied by scanning probe microscopy techniques.

    Science.gov (United States)

    Bolker, Asaf; Saguy, Cecile; Kalish, Rafi

    2014-09-26

    The transfer doping of diamond surfaces has been applied in various novel two-dimensional electronic devices. Its extension to nanodiamonds (ND) is essential for ND-based applications in many fields. In particular, understanding the influence of the crystallite size on transfer doping is desirable. Here, we report the results of a detailed study of the electronic energetic band structure of single, isolated transfer-doped nanodiamonds with nanometric resolution using a combination of scanning tunneling spectroscopy and Kelvin force microscopy measurements. The results show how the band gap, the valence band maximum, the electron affinity and the work function all depend on the ND's size and nanoparticle surface properties. The present analysis, which combines information from both scanning tunneling spectroscopy and Kelvin force microscopy, should be applicable to any nanoparticle or surface that can be measured with scanning probe techniques.

  3. Transfer doping of single isolated nanodiamonds, studied by scanning probe microscopy techniques

    Science.gov (United States)

    Bolker, Asaf; Saguy, Cecile; Kalish, Rafi

    2014-09-01

    The transfer doping of diamond surfaces has been applied in various novel two-dimensional electronic devices. Its extension to nanodiamonds (ND) is essential for ND-based applications in many fields. In particular, understanding the influence of the crystallite size on transfer doping is desirable. Here, we report the results of a detailed study of the electronic energetic band structure of single, isolated transfer-doped nanodiamonds with nanometric resolution using a combination of scanning tunneling spectroscopy and Kelvin force microscopy measurements. The results show how the band gap, the valence band maximum, the electron affinity and the work function all depend on the ND’s size and nanoparticle surface properties. The present analysis, which combines information from both scanning tunneling spectroscopy and Kelvin force microscopy, should be applicable to any nanoparticle or surface that can be measured with scanning probe techniques.

  4. Transfer doping of single isolated nanodiamonds, studied by scanning probe microscopy techniques

    International Nuclear Information System (INIS)

    Bolker, Asaf; Kalish, Rafi; Saguy, Cecile

    2014-01-01

    The transfer doping of diamond surfaces has been applied in various novel two-dimensional electronic devices. Its extension to nanodiamonds (ND) is essential for ND-based applications in many fields. In particular, understanding the influence of the crystallite size on transfer doping is desirable. Here, we report the results of a detailed study of the electronic energetic band structure of single, isolated transfer-doped nanodiamonds with nanometric resolution using a combination of scanning tunneling spectroscopy and Kelvin force microscopy measurements. The results show how the band gap, the valence band maximum, the electron affinity and the work function all depend on the ND’s size and nanoparticle surface properties. The present analysis, which combines information from both scanning tunneling spectroscopy and Kelvin force microscopy, should be applicable to any nanoparticle or surface that can be measured with scanning probe techniques. (paper)

  5. Probing cytotoxicity of nanoparticles and organic compounds using scanning proton microscopy, scanning electron microscopy and fluorescence microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tong Yongpeng [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China)], E-mail: yongpengt@yahoo.com.cn; Li Changming [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 637457 (Singapore); Liang Feng [Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200025 (China); Chen Jianmin [Shenzhen Municipal Hospital for Chronic Disease Control and Prevention, Guangdong 518020 (China); Zhang Hong; Liu Guoqing; Sun Huibin [Institute of Nuclear Techniques, Shenzhen University, Nanhai Avenue 3688, Shenzhen 518060 (China); Luong, John H.T. [Biotechnology Research Institute, National Research Council Canada, Montreal, Quebec, H4P 2R2 (Canada)

    2008-12-15

    Scanning proton microscopy, scanning electron microscopy (SEM) and fluorescence microscopy have been used to probe the cytotoxicity effect of benzo[a]pyrene (BaP), ethidium bromide (EB) and nanoparticles (ZnO, Al{sub 2}O{sub 3} and TiO{sub 2}) on a T lymphoblastic leukemia Jurkat cell line. The increased calcium ion (from CaCl{sub 2}) in the culture medium stimulated the accumulation of BaP and EB inside the cell, leading to cell death. ZnO, Al{sub 2}O{sub 3} and TiO{sub 2} nanoparticles, however, showed a protective effect against these two organic compounds. Such inorganic nanoparticles complexed with BaP or EB which became less toxic to the cell. Fe{sub 2}O{sub 3} nanoparticles as an insoluble particle model scavenged by macrophage were investigated in rats. They were scavenged out of the lung tissue about 48 h after infection. This result suggest that some insoluble inorganic nanoparticles of PM (particulate matters) showed protective effects on organic toxins induced acute toxic effects as they can be scavenged by macrophage cells. Whereas, some inorganic ions such as calcium ion in PM may help environmental organic toxins to penetrate cell membrane and induce higher toxic effect.

  6. Magnetic scanning gate microscopy of a domain wall nanosensor using microparticle probe

    Energy Technology Data Exchange (ETDEWEB)

    Corte-León, H., E-mail: hector.corte@npl.co.uk [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Royal Holloway University of London, Egham TW20 0EX (United Kingdom); Gribkov, B. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom); Krzysteczko, P. [Physikalisch-Technische Bundesanstalt, Braunschweig D-38116 (Germany); Marchi, F.; Motte, J.-F. [University of Grenoble Alpes, Inst. NEEL, Grenoble F-38042 (France); CNRS, Inst. NEEL, Grenoble F-38042 (France); Schumacher, H.W. [Physikalisch-Technische Bundesanstalt, Braunschweig D-38116 (Germany); Antonov, V. [Royal Holloway University of London, Egham TW20 0EX (United Kingdom); Kazakova, O. [National Physical Laboratory, Teddington TW11 0LW (United Kingdom)

    2016-02-15

    We apply the magnetic scanning gate microscopy (SGM) technique to study the interaction between a magnetic bead (MB) and a domain wall (DW) trapped in an L-shaped magnetic nanostructure. Magnetic SGM is performed using a custom-made probe, comprising a hard magnetic NdFeB bead of diameter 1.6 µm attached to a standard silicon tip. The MB–DW interaction is detected by measuring changes in the electrical resistance of the device as a function of the tip position. By scanning at different heights, we create a 3D map of the MB–DW interaction and extract the sensing volume for different widths of the nanostructure's arms. It is shown that for 50 nm wide devices the sensing volume is a cone of 880 nm in diameter by 1.4 µm in height, and reduces down to 800 nm in height for 100 nm devices with almost no change in its diameter. - Highlights: • AFM tips with a magnetic bead attached used to test interaction with domain wall. • Domain wall inside a nanostructure affect the electrical resistance. • Recording electrical resistance while scanning with modified AFM probe. • Change of resistance as a function of the position of the magnetic bead. • This allows comparing different devices in a reproducible and controllable way.

  7. Scanning Hall Probe Microscopy of Magnetic Vortices inVery Underdoped yttrium-barium-copper-oxide

    Energy Technology Data Exchange (ETDEWEB)

    Guikema, Janice Wynn; /SLAC, SSRL

    2005-12-02

    Since their discovery by Bednorz and Mueller (1986), high-temperature cuprate superconductors have been the subject of intense experimental research and theoretical work. Despite this large-scale effort, agreement on the mechanism of high-T{sub c} has not been reached. Many theories make their strongest predictions for underdoped superconductors with very low superfluid density n{sub s}/m*. For this dissertation I implemented a scanning Hall probe microscope and used it to study magnetic vortices in newly available single crystals of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} (Liang et al. 1998, 2002). These studies have disproved a promising theory of spin-charge separation, measured the apparent vortex size (an upper bound on the penetration depth {lambda}{sub ab}), and revealed an intriguing phenomenon of ''split'' vortices. Scanning Hall probe microscopy is a non-invasive and direct method for magnetic field imaging. It is one of the few techniques capable of submicron spatial resolution coupled with sub-{Phi}{sub 0} (flux quantum) sensitivity, and it operates over a wide temperature range. Chapter 2 introduces the variable temperature scanning microscope and discusses the scanning Hall probe set-up and scanner characterizations. Chapter 3 details my fabrication of submicron GaAs/AlGaAs Hall probes and discusses noise studies for a range of probe sizes, which suggest that sub-100 nm probes could be made without compromising flux sensitivity. The subsequent chapters detail scanning Hall probe (and SQUID) microscopy studies of very underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} crystals with T{sub c} {le} 15 K. Chapter 4 describes two experimental tests for visons, essential excitations of a spin-charge separation theory proposed by Senthil and Fisher (2000, 2001b). We searched for predicted hc/e vortices (Wynn et al. 2001) and a vortex memory effect (Bonn et al. 2001) with null results, placing upper bounds on the vison energy inconsistent with

  8. THE INTEGRATED USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY, AND VIRTUAL REALITY TO PREDICT THE CHEMICAL REACTIVITY OF ENVIRONMENTAL SURFACES

    Science.gov (United States)

    In the last decade three new techniques scanning probe microscopy (SPM), virtual reality (YR) and computational chemistry ave emerged with the combined capability of a priori predicting the chemically reactivity of environmental surfaces. Computational chemistry provides the cap...

  9. Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement.

    Science.gov (United States)

    Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua; Jia, Jin-Feng

    2015-05-01

    Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO3 surface.

  10. Development of micro-four-point probe in a scanning tunneling microscope for in situ electrical transport measurement

    Energy Technology Data Exchange (ETDEWEB)

    Ge, Jian-Feng; Liu, Zhi-Long; Gao, Chun-Lei; Qian, Dong; Liu, Canhua, E-mail: canhualiu@sjtu.edu.cn, E-mail: jfjia@sjtu.edu.cn; Jia, Jin-Feng, E-mail: canhualiu@sjtu.edu.cn, E-mail: jfjia@sjtu.edu.cn [Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

    2015-05-15

    Electrons at surface may behave differently from those in bulk of a material. Multi-functional tools are essential in comprehensive studies on a crystal surface. Here, we developed an in situ microscopic four-point probe (4PP) transport measurement system on the basis of a scanning tunneling microscope (STM). In particular, convenient replacement between STM tips and micro-4PPs enables systematic investigations of surface morphology, electronic structure, and electrical transport property of a same sample surface. Performances of the instrument are demonstrated with high-quality STM images, tunneling spectra, and low-noise electrical I-V characteristic curves of a single-layer FeSe film grown on a conductive SrTiO{sub 3} surface.

  11. Development of a detachable high speed miniature scanning probe microscope for large area substrates inspection

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghian, Hamed, E-mail: hamed.sadeghianmarnani@tno.nl, E-mail: h.sadeghianmarnani@tudelft.nl [Department of Optomechatronics, Netherlands Organization for Scientific Applied Research, TNO, Stieltjesweg 1, 2628 CK Delft (Netherlands); Department of Precision and Microsystems Engineering, Delft University of Technology, Mekelweg 2, 2628 CD Delft (Netherlands); Herfst, Rodolf; Winters, Jasper; Crowcombe, Will; Kramer, Geerten; Dool, Teun van den; Es, Maarten H. van [Department of Optomechatronics, Netherlands Organization for Scientific Applied Research, TNO, Stieltjesweg 1, 2628 CK Delft (Netherlands)

    2015-11-15

    We have developed a high speed, miniature scanning probe microscope (MSPM) integrated with a Positioning Unit (PU) for accurately positioning the MSPM on a large substrate. This combination enables simultaneous, parallel operation of many units on a large sample for high throughput measurements. The size of the MSPM is 19 × 45 × 70 mm{sup 3}. It contains a one-dimensional flexure stage with counter-balanced actuation for vertical scanning with a bandwidth of 50 kHz and a z-travel range of more than 2 μm. This stage is mechanically decoupled from the rest of the MSPM by suspending it on specific dynamically determined points. The motion of the probe, which is mounted on top of the flexure stage is measured by a very compact optical beam deflection (OBD). Thermal noise spectrum measurements of short cantilevers show a bandwidth of 2 MHz and a noise of less than 15 fm/Hz{sup 1/2}. A fast approach and engagement of the probe to the substrate surface have been achieved by integrating a small stepper actuator and direct monitoring of the cantilever response to the approaching surface. The PU has the same width as the MSPM, 45 mm and can position the MSPM to a pre-chosen position within an area of 275×30 mm{sup 2} to within 100 nm accuracy within a few seconds. During scanning, the MSPM is detached from the PU which is essential to eliminate mechanical vibration and drift from the relatively low-resonance frequency and low-stiffness structure of the PU. Although the specific implementation of the MSPM we describe here has been developed as an atomic force microscope, the general architecture is applicable to any form of SPM. This high speed MSPM is now being used in a parallel SPM architecture for inspection and metrology of large samples such as semiconductor wafers and masks.

  12. Low-Level Detection of Poly(amidoamine) PAMAM Dendrimers Using Immunoimaging Scanning Probe Microscopy

    OpenAIRE

    Cason, Chevelle A.; Fabré, Thomas A.; Buhrlage, Andrew; Haik, Kristi L.; Bullen, Heather A.

    2012-01-01

    Immunoimaging scanning probe microscopy was utilized for the low-level detection and quantification of biotinylated G4 poly(amidoamine) PAMAM dendrimers. Results were compared to those of high-performance liquid chromatography (HPLC) and found to provide a vastly improved analytical method for the low-level detection of dendrimers, improving the limit of detection by a factor of 1000 (LOD = 2.5 × 10−13 moles). The biorecognition method is reproducible and shows high specificity and good accur...

  13. Asymmetric actuating structure generates negligible influence on the supporting base for high performance scanning probe microscopies

    Science.gov (United States)

    Yi Yan, Gang; Bin Liu, Yong; Hua Feng, Zhi

    2014-02-01

    An asymmetric actuating structure generating negligible influence on the supporting base for high performance scanning probe microscopies is proposed in this paper. The actuator structure consists of two piezostacks, one is used for actuating while the other is for counterbalancing. In contrast with balanced structure, the two piezostacks are installed at the same side of the supporting base. The effectiveness of the structure is proved by some experiments with the actuators fixed to the free end of a cantilever. Experimental results show that almost all of the vibration modes of the cantilever are suppressed effectively at a wide frequency range of 90 Hz-10 kHz.

  14. Self-sensing cantilevers with integrated conductive coaxial tips for high-resolution electrical scanning probe metrology

    International Nuclear Information System (INIS)

    Haemmerli, Alexandre J.; Pruitt, Beth L.; Harjee, Nahid; Koenig, Markus; Garcia, Andrei G. F.; Goldhaber-Gordon, David

    2015-01-01

    The lateral resolution of many electrical scanning probe techniques is limited by the spatial extent of the electrostatic potential profiles produced by their probes. Conventional unshielded conductive atomic force microscopy probes produce broad potential profiles. Shielded probes could offer higher resolution and easier data interpretation in the study of nanostructures. Electrical scanning probe techniques require a method of locating structures of interest, often by mapping surface topography. As the samples studied with these techniques are often photosensitive, the typical laser measurement of cantilever deflection can excite the sample, causing undesirable changes electrical properties. In this work, we present the design, fabrication, and characterization of probes that integrate coaxial tips for spatially sharp potential profiles with piezoresistors for self-contained, electrical displacement sensing. With the apex 100 nm above the sample surface, the electrostatic potential profile produced by our coaxial tips is more than 2 times narrower than that of unshielded tips with no long tails. In a scan bandwidth of 1 Hz–10 kHz, our probes have a displacement resolution of 2.9 Å at 293 K and 79 Å at 2 K, where the low-temperature performance is limited by amplifier noise. We show scanning gate microscopy images of a quantum point contact obtained with our probes, highlighting the improvement to lateral resolution resulting from the coaxial tip

  15. Application of carbon nanotubes to topographical resolution enhancement of tapered fiber scanning near field optical microscopy probes

    Science.gov (United States)

    Huntington, S. T.; Jarvis, S. P.

    2003-05-01

    Scanning near field optical microscopy (SNOM) probes are typically tapered optical fibers with metallic coatings. The tip diameters are generally in excess of 300 nm and thus provide poor topographical resolution. Here we report on the attachment multiwalled carbon nanotubes to the probes in order to substantially enhance the topographical resolution, without adversely affecting the optical resolution.

  16. Waveguide analysis of heat-drawn and chemically etched probe tips for scanning near-field optical microscopy.

    Science.gov (United States)

    Moar, Peter N; Love, John D; Ladouceur, François; Cahill, Laurence W

    2006-09-01

    We analyze two basic aspects of a scanning near-field optical microscope (SNOM) probe's operation: (i) spot-size evolution of the electric field along the probe with and without a metal layer, and (ii) a modal analysis of the SNOM probe, particularly in close proximity to the aperture. A slab waveguide model is utilized to minimize the analytical complexity, yet provides useful quantitative results--including losses associated with the metal coating--which can then be used as design rules.

  17. Characterizing Surfaces of the Wide Bandgap Semiconductor Ilmenite with Scanning Probe Microcopies

    Science.gov (United States)

    Wilkins, R.; Powell, Kirk St. A.

    1997-01-01

    Ilmenite (FeTiO3) is a wide bandgap semiconductor with an energy gap of about 2.5eV. Initial radiation studies indicate that ilmenite has properties suited for radiation tolerant applications, as well as a variety of other electronic applications. Two scanning probe microscopy methods have been used to characterize the surface of samples taken from Czochralski grown single crystals. The two methods, atomic force microscopy (AFM) and scanning tunneling microscopy (STM), are based on different physical principles and therefore provide different information about the samples. AFM provides a direct, three-dimensional image of the surface of the samples, while STM give a convolution of topographic and electronic properties of the surface. We will discuss the differences between the methods and present preliminary data of each method for ilmenite samples.

  18. Growth of Pd-Filled Carbon Nanotubes on the Tip of Scanning Probe Microscopy

    Directory of Open Access Journals (Sweden)

    Tomokazu Sakamoto

    2009-01-01

    Full Text Available We have synthesized Pd-filled carbon nanotubes (CNTs oriented perpendicular to Si substrates using a microwave plasma-enhanced chemical vapor deposition (MPECVD for the application of scanning probe microscopy (SPM tip. Prior to the CVD growth, Al thin film (10 nm was coated on the substrate as a buffer layer followed by depositing a 5∼40 nm-thick Pd film as a catalyst. The diameter and areal density of CNTs grown depend largely on the initial Pd thickness. Scanning electron microscopy (SEM and transmission electron microscopy (TEM images clearly show that Pd is successfully encapsulated into the CNTs, probably leading to higher conductivity. Using optimum growth conditions, Pd-filled CNTs are successfully grown on the apex of the conventional SPM cantilever.

  19. Experimental Route to Scanning Probe Hot Electron Nanoscopy (HENs) Applied to 2D Material

    KAUST Repository

    Giugni, Andrea

    2017-06-09

    This paper presents details on a new experimental apparatus implementing the hot electron nanoscopy (HENs) technique introduced for advanced spectroscopies on structure and chemistry in few molecules and interface problems. A detailed description of the architecture used for the laser excitation of surface plasmons at an atomic force microscope (AFM) tip is provided. The photogenerated current from the tip to the sample is detected during the AFM scan. The technique is applied to innovative semiconductors for applications in electronics: 2D MoS2 single crystal and a p-type SnO layer. Results are supported by complementary scanning Kelvin probe microscopy, traditional conductive AFM, and Raman measurements. New features highlighted by HEN technique reveal details of local complexity in MoS2 and polycrystalline structure of SnO at nanometric scale otherwise undetected. The technique set in this paper is promising for future studies in nanojunctions and innovative multilayered materials, with new insight on interfaces.

  20. Three axis vector magnet set-up for cryogenic scanning probe microscopy

    International Nuclear Information System (INIS)

    Galvis, J. A.; Herrera, E.; Buendía, A.; Guillamón, I.; Vieira, S.; Suderow, H.; Azpeitia, J.; Luccas, R. F.; Munuera, C.; García-Hernandez, M.

    2015-01-01

    We describe a three axis vector magnet system for cryogenic scanning probe microscopy measurements. We discuss the magnet support system and the power supply, consisting of a compact three way 100 A current source. We obtain tilted magnetic fields in all directions with maximum value of 5T along z-axis and of 1.2T for XY-plane magnetic fields. We describe a scanning tunneling microscopy-spectroscopy (STM-STS) set-up, operating in a dilution refrigerator, which includes a new high voltage ultralow noise piezodrive electronics and discuss the noise level due to vibrations. STM images and STS maps show atomic resolution and the tilted vortex lattice at 150 mK in the superconductor β-Bi 2 Pd. We observe a strongly elongated hexagonal lattice, which corresponds to the projection of the tilted hexagonal vortex lattice on the surface. We also discuss Magnetic Force Microscopy images in a variable temperature insert

  1. Three axis vector magnet set-up for cryogenic scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Galvis, J. A. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias Universidad Autónoma de Madrid, 28049 Madrid (Spain); Departamento de Ciencias Naturales Facultad de Ingeniería Universidad Central, Bogotá (Colombia); Herrera, E.; Buendía, A. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias Universidad Autónoma de Madrid, 28049 Madrid (Spain); Guillamón, I.; Vieira, S.; Suderow, H. [Laboratorio de Bajas Temperaturas, Departamento de Física de la Materia Condensada, Instituto de Ciencia de Materiales Nicolás Cabrera, Condensed Matter Physics Center (IFIMAC), Facultad de Ciencias Universidad Autónoma de Madrid, 28049 Madrid (Spain); Unidad Asociada de Bajas Temperaturas y Altos Campos Magnéticos, UAM, CSIC, Cantoblanco, E-28049 Madrid (Spain); Azpeitia, J.; Luccas, R. F.; Munuera, C.; García-Hernandez, M. [Unidad Asociada de Bajas Temperaturas y Altos Campos Magnéticos, UAM, CSIC, Cantoblanco, E-28049 Madrid (Spain); Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC), Sor Juana Inés de la Cruz 3, 28049 Madrid (Spain); and others

    2015-01-15

    We describe a three axis vector magnet system for cryogenic scanning probe microscopy measurements. We discuss the magnet support system and the power supply, consisting of a compact three way 100 A current source. We obtain tilted magnetic fields in all directions with maximum value of 5T along z-axis and of 1.2T for XY-plane magnetic fields. We describe a scanning tunneling microscopy-spectroscopy (STM-STS) set-up, operating in a dilution refrigerator, which includes a new high voltage ultralow noise piezodrive electronics and discuss the noise level due to vibrations. STM images and STS maps show atomic resolution and the tilted vortex lattice at 150 mK in the superconductor β-Bi{sub 2}Pd. We observe a strongly elongated hexagonal lattice, which corresponds to the projection of the tilted hexagonal vortex lattice on the surface. We also discuss Magnetic Force Microscopy images in a variable temperature insert.

  2. ac driving amplitude dependent systematic error in scanning Kelvin probe microscope measurements: Detection and correction

    International Nuclear Information System (INIS)

    Wu Yan; Shannon, Mark A.

    2006-01-01

    The dependence of the contact potential difference (CPD) reading on the ac driving amplitude in scanning Kelvin probe microscope (SKPM) hinders researchers from quantifying true material properties. We show theoretically and demonstrate experimentally that an ac driving amplitude dependence in the SKPM measurement can come from a systematic error, and it is common for all tip sample systems as long as there is a nonzero tracking error in the feedback control loop of the instrument. We further propose a methodology to detect and to correct the ac driving amplitude dependent systematic error in SKPM measurements. The true contact potential difference can be found by applying a linear regression to the measured CPD versus one over ac driving amplitude data. Two scenarios are studied: (a) when the surface being scanned by SKPM is not semiconducting and there is an ac driving amplitude dependent systematic error; (b) when a semiconductor surface is probed and asymmetric band bending occurs when the systematic error is present. Experiments are conducted using a commercial SKPM and CPD measurement results of two systems: platinum-iridium/gap/gold and platinum-iridium/gap/thermal oxide/silicon are discussed

  3. Scanning probe microscopy studies on the adsorption of selected molecular dyes on titania

    Directory of Open Access Journals (Sweden)

    Jakub S. Prauzner-Bechcicki

    2016-11-01

    Full Text Available Titanium dioxide, or titania, sensitized with organic dyes is a very attractive platform for photovoltaic applications. In this context, the knowledge of properties of the titania–sensitizer junction is essential for designing efficient devices. Consequently, studies on the adsorption of organic dyes on titania surfaces and on the influence of the adsorption geometry on the energy level alignment between the substrate and an organic adsorbate are necessary. The method of choice for investigating the local environment of a single dye molecule is high-resolution scanning probe microscopy. Microscopic results combined with the outcome of common spectroscopic methods provide a better understanding of the mechanism taking place at the titania–sensitizer interface. In the following paper, we review the recent scanning probe microscopic research of a certain group of molecular assemblies on rutile titania surfaces as it pertains to dye-sensitized solar cell applications. We focus on experiments on adsorption of three types of prototypical dye molecules, i.e., perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA, phtalocyanines and porphyrins. Two interesting heteromolecular systems comprising molecules that are aligned with the given review are discussed as well.

  4. Touching is believing: interrogating halide perovskite solar cells at the nanoscale via scanning probe microscopy

    Science.gov (United States)

    Li, Jiangyu; Huang, Boyuan; Nasr Esfahani, Ehsan; Wei, Linlin; Yao, Jianjun; Zhao, Jinjin; Chen, Wei

    2017-10-01

    Halide perovskite solar cells based on CH3NH3PbI3 and related materials have emerged as the most exciting development in the next generation photovoltaic technologies, yet the microscopic phenomena involving photo-carriers, ionic defects, spontaneous polarization, and molecular vibration and rotation interacting with numerous grains, grain boundaries, and interfaces are still inadequately understood. In fact, there is still need for an effective method to interrogate the local photovoltaic properties of halide perovskite solar cells that can be directly traced to their microstructures on one hand and linked to their device performance on the other hand. In this perspective, we propose that scanning probe microscopy (SPM) techniques have great potential to realize such promises at the nanoscale, and highlight some of the recent progresses and challenges along this line of investigation toward local probing of photocurrent, work function, ionic activities, polarization switching, and chemical degradation. We also emphasize the importance of multi-modality imaging, in-operando scanning, big data analysis, and multidisciplinary collaboration for further studies toward fully understanding of these complex systems.

  5. Precise Orientation of a Single C60 Molecule on the Tip of a Scanning Probe Microscope

    Science.gov (United States)

    Chiutu, C.; Sweetman, A. M.; Lakin, A. J.; Stannard, A.; Jarvis, S.; Kantorovich, L.; Dunn, J. L.; Moriarty, P.

    2012-06-01

    We show that the precise orientation of a C60 molecule which terminates the tip of a scanning probe microscope can be determined with atomic precision from submolecular contrast images of the fullerene cage. A comparison of experimental scanning tunneling microscopy data with images simulated using computationally inexpensive Hückel theory provides a robust method of identifying molecular rotation and tilt at the end of the probe microscope tip. Noncontact atomic force microscopy resolves the atoms of the C60 cage closest to the surface for a range of molecular orientations at tip-sample separations where the molecule-substrate interaction potential is weakly attractive. Measurements of the C60C60 pair potential acquired using a fullerene-terminated tip are in excellent agreement with theoretical predictions based on a pairwise summation of the van der Waals interactions between C atoms in each cage, i.e., the Girifalco potential [L. Girifalco, J. Phys. Chem. 95, 5370 (1991)JPCHAX0022-365410.1021/j100167a002].

  6. Scanning thermo-ionic microscopy for probing local electrochemistry at the nanoscale

    Energy Technology Data Exchange (ETDEWEB)

    Eshghinejad, Ahmadreza; Nasr Esfahani, Ehsan; Wang, Peiqi; Li, Jiangyu, E-mail: jjli@uw.edu [Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 (United States); Xie, Shuhong [Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, Hunan (China); Shenzhen Key Laboratory of Nanobiomechanics, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, Guangdong (China); Geary, Timothy C.; Adler, Stuart B. [Department of Chemical Engineering, University of Washington, Seattle, Washington 98195 (United States)

    2016-05-28

    Conventional electrochemical characterization techniques based on voltage and current measurements only probe faradaic and capacitive rates in aggregate. In this work we develop a scanning thermo-ionic microscopy (STIM) to probe local electrochemistry at the nanoscale, based on imaging of Vegard strain induced by thermal oscillation. It is demonstrated from both theoretical analysis and experimental validation that the second harmonic response of thermally induced cantilever vibration, associated with thermal expansion, is present in all solids, whereas the fourth harmonic response, caused by local transport of mobile species, is only present in ionic materials. The origin of STIM response is further confirmed by its reduced amplitude with respect to increased contact force, due to the coupling of stress to concentration of ionic species and/or electronic defects. The technique has been applied to probe Sm-doped Ceria and LiFePO{sub 4}, both of which exhibit higher concentrations of mobile species near grain boundaries. The STIM gives us a powerful method to study local electrochemistry with high sensitivity and spatial resolution for a wide range of ionic systems, as well as ability to map local thermomechanical response.

  7. Acoustic field of focusing phased array probe and the scanning system

    International Nuclear Information System (INIS)

    Murai, J.; Miura, S.; Ida, T.; Shiraiwa, T.; Miya, T.

    1997-01-01

    Acoustic field of a point focusing cylindrical linear array probe, in which focusing in the axial direction of cylinder is done by the phased linear array and focusing in the orthogonal direction is done geometrically, was studied by numerical calculation and an optimum design of phased array probe for focusing has been obtained. In generally speaking, the beam width at focus point decreases with decrease of width of each transducer element and with increase of synthetic aperture made by total elements. If the number of total array elements excited as one pulse is limited, the above conditions are contradicted. Thus, an optimum element width exists for the best focusing. On the above consideration, we can get focusing ability of phased array nearly as same as geometrical focusing. A developed transducer is a linear array of polymer piezoelectric material of cylindrical shape, of which radius is from 50 mm to 75 mm. The frequency is 10 Mhz and the beam width of 0.5 mm (depending on aperture) in the orthogonal direction to the cylinder axis and 0.7 mm width in the cylinder axis (phased array focusing) have been obtained. A delay circuit for exciting the transducer was newly designed to give maximum performance to the array regarding to accuracy, stability, easy control and etc. A c-scan ultrasonic testing system equipped with this transducer has sixteen times inspection speed compared to the single probe instrument.

  8. Probing the local microwave properties of superconducting thin films by a scanning microwave near-field microscope

    CERN Document Server

    Wu, L Y; Wang, K L; Jiang, T; Kang, L; Yang, S Z; Wu, P H

    2002-01-01

    In this paper, we present our approach to probe the local microwave properties of superconducting thin films by using the microwave near-field scanning technique. We have employed a coaxial cavity together with a niobium tip as the probe and established a scanning sample stage cooled by liquid nitrogen to study thin film devices at low temperature in our scanning microwave near-field microscope. Nondestructive images have been obtained on the inhomogeneity of the YBaCuO superconducting thin films at microwave frequency. We believe that these results would be helpful in evaluating the microwave performance of the devices.

  9. Scanning-probe-microscopy of polyethylene terephthalate surface treatment by argon ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza-Beltran, Francisco [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico); Sanchez, Isaac C. [Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712 (United States); España-Sánchez, Beatriz L.; Mota-Morales, Josué D.; Carrillo, Salvador; Enríquez-Flores, C.I. [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico); Poncin-Epaillard, Fabienne, E-mail: epaill@univ-lemans.fr [Institute for Molecules and Materials, UMR CNRS 6283, Av. O. Messiaen, Universitè du Maine, Le Mans 72085 (France); Luna-Barcenas, Gabriel, E-mail: gluna@qro.cinvestav.mx [Polymer & Biopolymer Group, Libramiento Norponiente no. 2000, Cinvestav Queretaro, Queretaro 76230 (Mexico)

    2015-11-01

    Highlights: • Kelvin-probe-force microscopy helps study of PET surface treated by Ar ion beam. • Ar ion beam surface treatment promotes chain scission and N insertion. • Surface roughness and work function increases as intensity of ion energy increases. • Adhesive force of PET decrease due to the surface changes by ion bombardment. - Abstract: The effect of argon (Ar{sup +}) ion beam treatment on the surface of polyethylene terephthalate (PET) samples was studied by scanning probe microscopy (SPM) and the changes in surface topography were assessed by atomic force microscopy (AFM). Kelvin probe force microscopy (KPFM) sheds light of adhesion force between treated polymer films and a Pt/Cr probe under dry conditions, obtaining the contact potential difference of material. As a result of Ar{sup +} ion bombardment, important surface chemical changes were detected by X-ray photoelectron spectroscopy (XPS) measurements such as chains scission and incorporation of nitrogen species. Ion beam treatment increases the surface roughness from 0.49 ± 0.1 nm to 7.2 ± 0.1 nm and modify the surface potential of PET samples, decreasing the adhesive forces from 12.041 ± 2.1 nN to 5.782 ± 0.06 nN, and producing a slight increase in the electronic work function (Φ{sub e}) from 5.1 V (untreated) to 5.2 V (treated). Ar{sup +} ion beam treatment allows to potentially changing the surface properties of PET, modifying surface adhesion, improving surface chemical changes, wetting properties and surface potential of polymers.

  10. Suspended Cell Culture ANalysis (SCAN) Tool to Enhance ISS On-Orbit Capabilities, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Aurora Flight Sciences and partner, Draper Laboratory, propose to develop an on-orbit immuno-based label-free Suspension Cell Culture ANalysis tool, SCAN tool, which...

  11. Deceleration of probe beam by stage bias potential improves resolution of serial block-face scanning electron microscopic images.

    Science.gov (United States)

    Bouwer, James C; Deerinck, Thomas J; Bushong, Eric; Astakhov, Vadim; Ramachandra, Ranjan; Peltier, Steven T; Ellisman, Mark H

    2017-01-01

    Serial block-face scanning electron microscopy (SBEM) is quickly becoming an important imaging tool to explore three-dimensional biological structure across spatial scales. At probe-beam-electron energies of 2.0 keV or lower, the axial resolution should improve, because there is less primary electron penetration into the block face. More specifically, at these lower energies, the interaction volume is much smaller, and therefore, surface detail is more highly resolved. However, the backscattered electron yield for metal contrast agents and the backscattered electron detector sensitivity are both sub-optimal at these lower energies, thus negating the gain in axial resolution. We found that the application of a negative voltage (reversal potential) applied to a modified SBEM stage creates a tunable electric field at the sample. This field can be used to decrease the probe-beam-landing energy and, at the same time, alter the trajectory of the signal to increase the signal collected by the detector. With decelerated low landing-energy electrons, we observed that the probe-beam-electron-penetration depth was reduced to less than 30 nm in epoxy-embedded biological specimens. Concurrently, a large increase in recorded signal occurred due to the re-acceleration of BSEs in the bias field towards the objective pole piece where the detector is located. By tuning the bias field, we were able to manipulate the trajectories of the  primary and secondary electrons, enabling the spatial discrimination of these signals using an advanced ring-type BSE detector configuration or a standard monolithic BSE detector coupled with a blocking aperture.

  12. [Comparison of the M and XL FibroScan(®) probes to estimate liver stiffness by transient elastography].

    Science.gov (United States)

    Herrero, José Ignacio; Iñarrairaegui, Mercedes; D'Avola, Delia; Sangro, Bruno; Prieto, Jesús; Quiroga, Jorge

    2014-04-01

    The FibroScan(®) XL probe has been specifically designed for obese patients to measure liver stiffness by transient elastography, but it has not been well tested in non-obese patients. The aim of this study was to compare the M and XL FibroScan(®) probes in a series of unselected obese (body mass index above 30 kg/m(2)) and non-obese patients with chronic liver disease. Two hundred and fifty-four patients underwent a transient elastography examination with both the M and XL probes. The results obtained with the two probes were compared in the whole series and in obese (n=82) and non-obese (n=167) patients separately. The reliability of the examinations was assessed using the criteria defined by Castéra et al. The proportion of reliable exams was significantly higher when the XL probe was used (83% versus 73%; P=.001). This significance was maintained in the group of obese patients (82% versus 55%; P<.001), but not in the non-obese patients (84% versus 83%). Despite a high correlation between the stiffness values obtained with the two probes (R=.897; P<.001), and a high concordance in the estimation of fibrosis obtained with the two probes (Cronbach's alpha value: 0.932), the liver stiffness values obtained with the XL probe were significantly lower than those obtained with the M probe, both in the whole series (9.5 ± 9.1 kPa versus 11.3 ± 12.6 kPa; P<0.001) and in the obese and non-obese groups. In conclusion, transient elastography with the XL probe allows a higher proportion of reliable examinations in obese patients but not in non-obese patients. Stiffness values were lower with the XL probe than with the M probe. Copyright © 2013 Elsevier España, S.L. and AEEH y AEG. All rights reserved.

  13. Investigation of the Radial Compression of Carbon Nanotubes with a Scanning Probe Microscope

    Science.gov (United States)

    Shen, Weidian; Jiang, Bin; Han, Bao Shan; Xie, Si-Shen

    2001-03-01

    Carbon nanotubes have attracted great interest since they were first synthesized. The tubes have substantial promise in a variety of applications due to their unique properties. Efforts have been made to characterize the mechanical properties of the tubes. However, previous work has concentrated on the tubes’ longitudinal properties, and studies of their radial properties lag behind. We have operated a scanning probe microscope, NanoScopeTM IIIa, in the indentation/scratching mode to carry out a nanoindentation test on the top of multiwalled carbon nanotubes. We measured the correlation between the radial stress and the tube compression, and thereby determined the radial compressive elastic modulus at different compressive forces. The measurements also allowed us to estimate the radial compressive strength of the tubes. Support of this work by an Eastern Michigan University Faculty Research Fellowship and by the K. C. Wong Education Foundation, Hong Kong is gratefully acknowledged.

  14. Quantitative characterization of crosstalk effects for friction force microscopy with scan-by-probe SPMs

    Energy Technology Data Exchange (ETDEWEB)

    Prunici, Pavel [Institute of Physical Chemistry, University of Heidelberg, D-69120 Heidelberg (Germany); Hess, Peter [Institute of Physical Chemistry, University of Heidelberg, D-69120 Heidelberg (Germany)], E-mail: peter.hess@urz.uni-heidelberg.de

    2008-06-15

    If the photodetector and cantilever of an atomic force microscope (AFM) are not properly adjusted, crosstalk effects will appear. These effects disturb measurements of the absolute vertical and horizontal cantilever deflections, which are involved in friction force microscopy (FFM). A straightforward procedure is proposed to study quantitatively crosstalk effects observed in scan-by-probe SPMs. The advantage of this simple, fast, and accurate procedure is that no hardware change or upgrade is needed. The results indicate that crosstalk effects depend not only on the alignment of the detector but also on the cantilever properties, position, and detection conditions. The measurements may provide information on the origin of the crosstalk effect. After determination of its magnitude, simple correction formulas can be applied to correct the crosstalk effects and then the single-load wedge method, using a commercially available grating, can be employed for accurate calibration of the lateral force.

  15. Standardization of nanomaterials characterization by scanning probe microscopy for societal acceptance

    International Nuclear Information System (INIS)

    Fujita, Daisuke; Onishi, Keiko; Xu, Mingsheng

    2009-01-01

    Novel nanomaterials are expected to play key roles for the promotion of innovations in the various industrial products. In order to make such novel nanomaterials to be socially acceptable and widely used, it is very important and necessary to establish the reliable nano-characterization methodology for the industrial nanomaterials under the authorized international scheme for standardization. Among the nano-characterization methods, scanning probe microscopy (SPM) is the most versatile both in the measurement functions and the operational environments. Whereas there are various nanomaterials of industrial application, fullerene nanomaterials (FNM) have attracted much attention due to their unique physical properties. Here we show the importance of the quantitative analysis and standardization of SPM using FNM as a typical example.

  16. Frequency Response of the Sample Vibration Mode in Scanning Probe Acoustic Microscope

    International Nuclear Information System (INIS)

    Ya-Jun, Zhao; Qian, Cheng; Meng-Lu, Qian

    2010-01-01

    Based on the interaction mechanism between tip and sample in the contact mode of a scanning probe acoustic microscope (SPAM), an active mass of the sample is introduced in the mass-spring model. The tip motion and frequency response of the sample vibration mode in the SPAM are calculated by the Lagrange equation with dissipation function. For the silicon tip and glass assemblage in the SPAM the frequency response is simulated and it is in agreement with the experimental result. The living myoblast cells on the glass slide are imaged at resonance frequencies of the SPAM system, which are 20kHz, 30kHz and 120kHz. It is shown that good contrast of SPAM images could be obtained when the system is operated at the resonance frequencies of the system in high and low-frequency regions

  17. Note: Microelectrode-shielding tip for scanning probe electron energy spectroscopy

    Science.gov (United States)

    Huang, Wei; Li, Zhean; Xu, Chunkai; Liu, Jian; Xu, Chunye; Chen, Xiangjun

    2018-04-01

    We report a novel microelectrode-shielding tip (ME tip) for scanning probe electron energy spectroscopy (SPEES). The shielding effect of this tip is studied through comparing the detection efficiency with the normal tip by both experiment and simulation. The results show that the backscattering count rate detected by the SPEES instrument using the normal tip begins to decrease as the tip approaches to the sample surface within 21 μm, while that using the ME tip only starts to drop off within 1 μm. This indicates that the electron energy spectra can be measured with the ME tip at a much closer tip-sample distance. Furthermore, it is also demonstrated that the ME tip can be used to obtain topography of the sample surface in situ simultaneously.

  18. Quantitative characterization of crosstalk effects for friction force microscopy with scan-by-probe SPMs

    International Nuclear Information System (INIS)

    Prunici, Pavel; Hess, Peter

    2008-01-01

    If the photodetector and cantilever of an atomic force microscope (AFM) are not properly adjusted, crosstalk effects will appear. These effects disturb measurements of the absolute vertical and horizontal cantilever deflections, which are involved in friction force microscopy (FFM). A straightforward procedure is proposed to study quantitatively crosstalk effects observed in scan-by-probe SPMs. The advantage of this simple, fast, and accurate procedure is that no hardware change or upgrade is needed. The results indicate that crosstalk effects depend not only on the alignment of the detector but also on the cantilever properties, position, and detection conditions. The measurements may provide information on the origin of the crosstalk effect. After determination of its magnitude, simple correction formulas can be applied to correct the crosstalk effects and then the single-load wedge method, using a commercially available grating, can be employed for accurate calibration of the lateral force

  19. Study of mechanically stimulated ferroelectric domain formation using scanning probe microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J H; Baek, J; Khim, Z G [School of Physics and Nano-Systems Institute, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2007-03-15

    The stress-related ferroelectric properties have been studied on the Triglycine sulfate (TGS) by scanning probe microscope (SPM). Together with normal stress of the tip, the lateral stress is applied to the sample with piezoelectric transducers. With this study, we characterized the way the ferroelectricity of TGS responds to the axis-specific stress. Specially, the b-directional stress applicable to the surface can amount to several GPa such that the polarization switching by mechanical stress is observable. Although the lateral stress is not strong enough to view such phenomena, a-axis(c-axis) stress still affects the polarization value so as to fortify (lessen) the electric field inside, respectively. These contrasting results can be explained by the sign relation of piezo-coefficients about the individual axis. This work can be a touchstone of future researches in characterizing the electromechanical properties of more popular ferroelectrics such as PZT or BTO.

  20. Standardization of nanomaterials characterization by scanning probe microscopy for societal acceptance

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, Daisuke [International Center for Materials Nanoarchitectonics (MANA) and Advanced Nano Characterization Center (ANCC), National Institute for Materials Science - NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Onishi, Keiko [Advanced Nano Characterization Center (ANCC), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Xu, Mingsheng [International Center for Young Scientists-Interdisciplinary Materials Research (ICYS-IMAT), National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)], E-mail: fujita.daisuke@nims.go.jp

    2009-04-01

    Novel nanomaterials are expected to play key roles for the promotion of innovations in the various industrial products. In order to make such novel nanomaterials to be socially acceptable and widely used, it is very important and necessary to establish the reliable nano-characterization methodology for the industrial nanomaterials under the authorized international scheme for standardization. Among the nano-characterization methods, scanning probe microscopy (SPM) is the most versatile both in the measurement functions and the operational environments. Whereas there are various nanomaterials of industrial application, fullerene nanomaterials (FNM) have attracted much attention due to their unique physical properties. Here we show the importance of the quantitative analysis and standardization of SPM using FNM as a typical example.

  1. Optimal design and fabrication of three-dimensional calibration specimens for scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xiaoning; Luo Tingting; Chen Yuhang; Huang Wenhao [Department of Precision Machinery and Instrumentation, University of Science and Technology of China, 230026 Hefei (China); Piaszenski, Guido [Raith GmbH, Konrad-Adenauer-Allee 8, 44263 Dortmund (Germany)

    2012-05-15

    Micro-/nano-scale roughness specimens are highly demanded to synthetically calibrate the scanning probe microscopy (SPM) instrument. In this study, three-dimensional (3D) specimens with controllable main surface evaluation parameters were designed. In order to improve the design accuracy, the genetic algorithm was introduced into the conventional digital filter method. A primary 3D calibration specimen with the dimension of 10 {mu}m x 10 {mu}m was fabricated by electron beam lithography. Atomic force microscopy characterizations demonstrated that the statistical and spectral parameters of the fabricated specimen match well with the designed values. Such a kind of 3D specimens has the potential to calibrate the SPM for applications in quantitative surface evaluations.

  2. Vibration Isolation Study in Scanning Probe Microscopy Part I: Low Frequency

    International Nuclear Information System (INIS)

    Oliva, A.I.; Espinosa-Faller, F.J.; Aguilar, M.

    1998-01-01

    A study of a low frequency isolation device based in a pneumatic system is presented. It consists of four cylinders which are closed and sealed with an elastic membrane on which the load is applied. Each cylinder made of PVC is formed by two chambers divided by a plate with a small hole for communication and damping. Air contained into chambers acts, in combination with the the elastic membranes, as a damper. Scanning probe techniques can be supported by this device in order to reduce the low frequency noises that affects them. Advantages of this isolator are discussed and compared. A theoretical approximation for this model is presented and compared with the experimental results obtained and show that it can isolate noises up to ∼ 2 Hz. The low frequency isolator has stability and fast response to external perturbations. This simple and economical low frequency isolator can be reproduced easily and its design depends on the work specific requirements. (Author) 9 refs

  3. Mapping degenerate vortex states in a kagome lattice of elongated antidots via scanning Hall probe microscopy

    Science.gov (United States)

    Xue, C.; Ge, J.-Y.; He, A.; Zharinov, V. S.; Moshchalkov, V. V.; Zhou, Y. H.; Silhanek, A. V.; Van de Vondel, J.

    2017-07-01

    We investigate the degeneracy of the superconducting vortex matter ground state by directly visualizing the vortex configurations in a kagome lattice of elongated antidots via scanning Hall probe microscopy. The observed vortex patterns, at specific applied magnetic fields, are in good agreement with the configurations obtained using time-dependent Ginzburg-Landau simulations. Both results indicate that the long-range interaction in this nanostructured superconductor is unable to lift the degeneracy between different vortex states and the pattern formation is mainly ruled by the nearest-neighbor interaction. This simplification makes it possible to identify a set of simple rules characterizing the vortex configurations. We demonstrate that these rules can explain both the observed vortex distributions and the magnetic-field-dependent degree of degeneracy.

  4. In situ scanning probe spectroscopy at nanoscale solid/liquid interfaces

    International Nuclear Information System (INIS)

    Schindler, W.; Hugelmann, M.; Hugelmann, Ph.

    2005-01-01

    Electrochemistry provides unique features for the preparation of low-dimensional structures, but in situ spectroscopy with atomic/molecular resolution at such structures is at present not well established yet. This paper shows that in situ scanning probe spectroscopy at solid/liquid interfaces can be utilized to study electronic properties at nanoscale, if appropriate conditions are applied. Tunneling spectroscopy provides information about tunneling barrier heights and electronic states in the tunneling gap, as shown on Au(1 1 1) substrates, contact spectroscopy allows for transport measurements at single nanostructures, as shown at Au/n-Si(1 1 1) nanodiodes. The influence of the electrolytic environment on spectroscopic investigations is not a principal limitation, but offers additional degrees of freedom, which allow, for example, spectroscopic studies of potential dependent surface phenomena at solid/liquid interfaces

  5. Electrical Potential of Acupuncture Points: Use of a Noncontact Scanning Kelvin Probe

    Directory of Open Access Journals (Sweden)

    Brian J. Gow

    2012-01-01

    Full Text Available Objective. Acupuncture points are reportedly distinguishable by their electrical properties. However, confounders arising from skin-to-electrode contact used in traditional electrodermal methods have contributed to controversies over this claim. The Scanning Kelvin Probe is a state-of-the-art device that measures electrical potential without actually touching the skin and is thus capable of overcoming these confounding effects. In this study, we evaluated the electrical potential profiles of acupoints LI-4 and PC-6 and their adjacent controls. We hypothesize that acupuncture point sites are associated with increased variability in potential compared to adjacent control sites. Methods. Twelve healthy individuals were recruited for this study. Acupuncture points LI-4 and PC-6 and their adjacent controls were assessed. A 2 mm probe tip was placed over the predetermined skin site and adjusted to a tip-to-sample distance of 1.0 mm under tip oscillation settings of 62.4 Hz frequency. A surface potential scan spanning a 1.0 cm × 1.0 cm area was obtained. Results. At both the PC-6 and LI-4 sites, no significant differences in mean potential were observed compared to their respective controls (Wilcoxon rank-sum test, and 0.79, resp.. However, the LI-4 site was associated with significant increase in variability compared to its control as denoted by standard deviation and range ( and 0.0005, resp.. At the PC-6 site, no statistical differences in variability were observed. Conclusion. Acupuncture points may be associated with increased variability in electrical potential.

  6. Characterization of power induced heating and damage in fiber optic probes for near-field scanning optical microscopy

    Science.gov (United States)

    Dickenson, Nicholas E.; Erickson, Elizabeth S.; Mooren, Olivia L.; Dunn, Robert C.

    2007-05-01

    Tip-induced sample heating in near-field scanning optical microscopy (NSOM) is studied for fiber optic probes fabricated using the chemical etching technique. To characterize sample heating from etched NSOM probes, the spectra of a thermochromic polymer sample are measured as a function of probe output power, as was previously reported for pulled NSOM probes. The results reveal that sample heating increases rapidly to ˜55-60°C as output powers reach ˜50nW. At higher output powers, the sample heating remains approximately constant up to the maximum power studied of ˜450nW. The sample heating profiles measured for etched NSOM probes are consistent with those previously measured for NSOM probes fabricated using the pulling method. At high powers, both pulled and etched NSOM probes fail as the aluminum coating is damaged. For probes fabricated in our laboratory we find failure occurring at input powers of 3.4±1.7 and 20.7±6.9mW for pulled and etched probes, respectively. The larger half-cone angle for etched probes (˜15° for etched and ˜6° for pulled probes) enables more light delivery and also apparently leads to a different failure mechanism. For pulled NSOM probes, high resolution images of NSOM probes as power is increased reveal the development of stress fractures in the coating at a taper diameter of ˜6μm. These stress fractures, arising from the differential heating expansion of the dielectric and the metal coating, eventually lead to coating removal and probe failure. For etched tips, the absence of clear stress fractures and the pooled morphology of the damaged aluminum coating following failure suggest that thermal damage may cause coating failure, although other mechanisms cannot be ruled out.

  7. Low-Temperature Reduction of Graphene Oxide: Electrical Conductance and Scanning Kelvin Probe Force Microscopy

    Science.gov (United States)

    Slobodian, Oleksandr M.; Lytvyn, Peter M.; Nikolenko, Andrii S.; Naseka, Victor M.; Khyzhun, Oleg Yu.; Vasin, Andrey V.; Sevostianov, Stanislav V.; Nazarov, Alexei N.

    2018-05-01

    Graphene oxide (GO) films were formed by drop-casting method and were studied by FTIR spectroscopy, micro-Raman spectroscopy (mRS), X-ray photoelectron spectroscopy (XPS), four-points probe method, atomic force microscopy (AFM), and scanning Kelvin probe force (SKPFM) microscopy after low-temperature annealing at ambient conditions. It was shown that in temperature range from 50 to 250 °C the electrical resistivity of the GO films decreases by seven orders of magnitude and is governed by two processes with activation energies of 6.22 and 1.65 eV, respectively. It was shown that the first process is mainly associated with water and OH groups desorption reducing the thickness of the film by 35% and causing the resistivity decrease by five orders of magnitude. The corresponding activation energy is the effective value determined by desorption and electrical connection of GO flakes from different layers. The second process is mainly associated with desorption of oxygen epoxy and alkoxy groups connected with carbon located in the basal plane of GO. AFM and SKPFM methods showed that during the second process, first, the surface of GO plane is destroyed forming nanostructured surface with low work function and then at higher temperature a flat carbon plane is formed that results in an increase of the work function of reduced GO.

  8. Scanning probe microscopy investigation of gold clusters deposited on atomically flat substrates

    International Nuclear Information System (INIS)

    Vandamme, N; Janssens, E; Vanhoutte, F; Lievens, P; Haesendonck, C van

    2003-01-01

    We systematically studied the influence of the substrate on the shape, mobility, and stability of deposited gold clusters. The Au n clusters were produced in a laser vaporization source and deposited with low kinetic energy (∼0.4 eV/atom) on atomically flat substrates (graphite, mica, and gold and silver films on mica) under UHV conditions. Their size distribution is probed with time-of-flight mass spectrometry and ranges from dimers to several hundreds of atoms. Scanning probe microscopy is used to characterize the deposited clusters and the formation of islands by cluster aggregation. On all substrates, Au n islands can be clearly distinguished and the islands are flattened despite the small impact energy. The shape and size of the island configurations are strongly system dependent. Gold clusters deposited on Au(111) and Ag(111) films grown on mica do not aggregate, but deform due to strong cluster-substrate interactions. The clusters tend to grow epitaxially on these surfaces. On graphite and on mica, deposited clusters do diffuse and aggregate. On the graphite surface, large ramified islands are formed by juxtaposition of small islands and trapping of the clusters at the step edges. On the other hand, the diffusion of the clusters on mica results in a total coalescence of the Au n clusters into compact islands

  9. Static states and dynamic behaviour of charges: observation and control by scanning probe microscopy

    International Nuclear Information System (INIS)

    Ishii, Masashi

    2010-01-01

    This paper reviews charges that locally functionalize materials. Microscopic analyses and operation of charges using various scanning probe microscopy (SPM) techniques have revealed static, quasi-static/quasi-dynamic and dynamic charge behaviours. Charge-sensitive SPM has allowed for the visualization of the distribution of functionalized charges in electronic devices. When used as bit data in a memory system, the charges can be operated by SPM. The behaviour of quasi-static/quasi-dynamic charges is discussed here. In the data-writing process, spatially dispersive charges rather than a fast injection rate are introduced, but the technical problems can be solved by using nanostructures. Careful charge operations using SPM should realize a memory with a larger density than Tbit/inch 2 . Dynamic charges have been introduced in physical analyses and chemical processes. Although the observable timescale is limited by the SPM system response time of the order of several seconds, dynamics such as photon-induced charge redistributions and probe-assisted chemical reactions are observed. (topical review)

  10. Static states and dynamic behaviour of charges: observation and control by scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, Masashi, E-mail: ISHII.Masashi@nims.go.j [National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2010-05-05

    This paper reviews charges that locally functionalize materials. Microscopic analyses and operation of charges using various scanning probe microscopy (SPM) techniques have revealed static, quasi-static/quasi-dynamic and dynamic charge behaviours. Charge-sensitive SPM has allowed for the visualization of the distribution of functionalized charges in electronic devices. When used as bit data in a memory system, the charges can be operated by SPM. The behaviour of quasi-static/quasi-dynamic charges is discussed here. In the data-writing process, spatially dispersive charges rather than a fast injection rate are introduced, but the technical problems can be solved by using nanostructures. Careful charge operations using SPM should realize a memory with a larger density than Tbit/inch{sup 2}. Dynamic charges have been introduced in physical analyses and chemical processes. Although the observable timescale is limited by the SPM system response time of the order of several seconds, dynamics such as photon-induced charge redistributions and probe-assisted chemical reactions are observed. (topical review)

  11. Chimpanzees create and modify probe tools functionally: A study with zoo-housed chimpanzees.

    Science.gov (United States)

    Hopper, Lydia M; Tennie, Claudio; Ross, Stephen R; Lonsdorf, Elizabeth V

    2015-02-01

    Chimpanzees (Pan troglodytes) use tools to probe for out-of-reach food, both in the wild and in captivity. Beyond gathering appropriately-sized materials to create tools, chimpanzees also perform secondary modifications in order to create an optimized tool. In this study, we recorded the behavior of a group of zoo-housed chimpanzees when presented with opportunities to use tools to probe for liquid foods in an artificial termite mound within their enclosure. Previous research with this group of chimpanzees has shown that they are proficient at gathering materials from within their environment in order to create tools to probe for the liquid food within the artificial mound. Extending beyond this basic question, we first asked whether they only made and modified probe tools when it was appropriate to do so (i.e. when the mound was baited with food). Second, by collecting continuous data on their behavior, we also asked whether the chimpanzees first (intentionally) modified their tools prior to probing for food or whether such modifications occurred after tool use, possibly as a by-product of chewing and eating the food from the tools. Following our predictions, we found that tool modification predicted tool use; the chimpanzees began using their tools within a short delay of creating and modifying them, and the chimpanzees performed more tool modifying behaviors when food was available than when they could not gain food through the use of probe tools. We also discuss our results in terms of the chimpanzees' acquisition of the skills, and their flexibility of tool use and learning. © 2014 Wiley Periodicals, Inc.

  12. Atomic species recognition on oxide surfaces using low temperature scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zong Min, E-mail: mzmncit@163.com [National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, 030051 (China); Key Laboratory of Instrumentation Science & Dynamic Measurement, North University of China, Ministry of Education, Taiyuan, 030051 (China); School of Instrument and Electronics, North University of China, Taiyuan, 030051 (China); Shi, Yun Bo; Mu, Ji Liang; Qu, Zhang; Zhang, Xiao Ming; Qin, Li [National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, 030051 (China); Key Laboratory of Instrumentation Science & Dynamic Measurement, North University of China, Ministry of Education, Taiyuan, 030051 (China); School of Instrument and Electronics, North University of China, Taiyuan, 030051 (China); Liu, Jun, E-mail: liuj@nuc.edu.cn [National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, 030051 (China); Key Laboratory of Instrumentation Science & Dynamic Measurement, North University of China, Ministry of Education, Taiyuan, 030051 (China); School of Instrument and Electronics, North University of China, Taiyuan, 030051 (China)

    2017-02-01

    Highlights: • The coexisted phase of p(2 × 1)and c(6 × 2) on Cu(110)-O surface using AFM under UHV at low temperature. • Two different c(6 × 2) phase depending on the status of the tip apex. • Electronic state of tip seriously effect the resolution and stability of the sample surface. - Abstract: In scanning probe microscopy (SPM), the chemical properties and sharpness of the tips of the cantilever greatly influence the scanning of a sample surface. Variation in the chemical properties of the sharp tip apex can induce transformation of the SPM images. In this research, we explore the relationship between the tip and the structure of a sample surface using dynamic atomic force microscopy (AFM) on a Cu(110)-O surface under ultra-high vacuum (UHV) at low temperature (78 K). We observed two different c(6 × 2) phase types in which super-Cu atoms show as a bright spot when the tip apex is of O atoms and O atoms show as a bright spot when the tip apex is of Cu atoms. We also found that the electronic state of the tip has a serious effect on the resolution and stability of the sample surface, and provide an explanation for these phenomena. This technique can be used to identify atom species on sample surfaces, and represents an important development in the SPM technique.

  13. Digitally controlled analog proportional-integral-derivative (PID) controller for high-speed scanning probe microscopy

    Science.gov (United States)

    Dukic, Maja; Todorov, Vencislav; Andany, Santiago; Nievergelt, Adrian P.; Yang, Chen; Hosseini, Nahid; Fantner, Georg E.

    2017-12-01

    Nearly all scanning probe microscopes (SPMs) contain a feedback controller, which is used to move the scanner in the direction of the z-axis in order to maintain a constant setpoint based on the tip-sample interaction. The most frequently used feedback controller in SPMs is the proportional-integral (PI) controller. The bandwidth of the PI controller presents one of the speed limiting factors in high-speed SPMs, where higher bandwidths enable faster scanning speeds and higher imaging resolution. Most SPM systems use digital signal processor-based PI feedback controllers, which require analog-to-digital and digital-to-analog converters. These converters introduce additional feedback delays which limit the achievable imaging speed and resolution. In this paper, we present a digitally controlled analog proportional-integral-derivative (PID) controller. The controller implementation allows tunability of the PID gains over a large amplification and frequency range, while also providing precise control of the system and reproducibility of the gain parameters. By using the analog PID controller, we were able to perform successful atomic force microscopy imaging of a standard silicon calibration grating at line rates up to several kHz.

  14. A proximal retarding field analyzer for scanning probe energy loss spectroscopy

    Science.gov (United States)

    Bauer, Karl; Murphy, Shane; Palmer, Richard E.

    2017-03-01

    A compact proximal retarding field analyzer for scanning probe energy loss spectroscopy measurements is described. Using the scanning tunneling microscope (STM) tip as a field emission (FE) electron source in conjunction with this analyzer, which is placed at a glancing angle to the surface plane, FE sample current and electron reflectivity imaging may be performed simultaneously. This is demonstrated in measurements of Ag nanostructures prepared on graphite by electron-beam lithography, where a material contrast of 13% is observed, with a lateral resolution of 25 nm, between the silver and graphite in electron reflectivity images. Topological contrast mechanisms such as edge enhancement and shadowing are also observed, giving rise to additional features in the electron reflectivity images. The same instrument configuration has been used to measure electron energy loss spectra on bare graphite, where the zero loss peak, π band plasmon loss peak and secondary electron peaks are observed. Using this simple and compact analyzer an STM, with sufficient open access to the tip-sample junction, may easily be augmented to provide simultaneous elemental and topographic mapping, supplementing STM image measurements with FE sample current and electron reflectivity images, as well as electron energy loss spectroscopy measurements, in the same instrument.

  15. 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.

  16. Electrocrystallization and scanning probe microscopy of ceramic thin films and superlattices

    Science.gov (United States)

    Hung, Chen-Jen

    This dissertation presents an investigation of the electrocrystallization and scanning probe microscopy of ceramic thin films and superlattices. All of the films were deposited from aqueous solution at room temperature with no subsequent heat treatment needed to effect crystallization. Thallium(III) oxide defect chemistry superlattices were electrodeposited by pulsing the applied overpotential during deposition. The defect chemistry of the oxide is dependent on the applied overpotential. High overpotentials favor oxygen vacancies, while low overpotentials favor cation interstitials. Nanometer-scale holes were formed in thin thallium(III) oxide films using the scanning tunneling microscope in humid ambient conditions. Both cathodic and anodic etching reactions were performed on this metal oxide surface. The hole formation was attributed to localized electrochemical etching reactions beneath the STM tip. The scanning tunneling microscope (STM) was also used to both induce local surface modifications and image cleaved Pb-Tl-O superlattices. A trench of 100 nm in width, 32 nm in depth, and over 1 μm in length was formed after sweeping a bias voltage of ±2.5 V for 1 minute using a fixed STM tip. It has been suggested that STM results obtained under ambient conditions must be evaluated with great care because of the possibility of localized electrochemcial reactions. A novel synthesis method for the production of Cu(II) oxide from an alkaline solution containing Cu(II) tartrate was developed. Rietveld refinement of the cupric oxide films reveals pure Cu(II) oxide with no Cu(I) oxide present in the film.

  17. Scanning tunneling microscopy: A powerful tool for surface analysis

    International Nuclear Information System (INIS)

    Walle, G.F.A. van de; Nelissen, B.J.; Soethout, L.L.; Kempen, H. van

    1987-01-01

    The invention of the Scanning Tunneling Microscope (STM) has opened a new area of surface analysis. A description of the principle of operation is given in this paper. Also the technical problems encountered and their solution are described. Two examples demonstrating the possibilities of the STM are presented: topographic and spectroscopic measurements on a stepped Ni (111) surface and photoconductive measurements on GaAs. (orig.)

  18. Radioactive probes as diagnostic tools for rice tungro viruses

    International Nuclear Information System (INIS)

    Azzam, O.; Arboleda, M.; Reyes. J. de los

    1996-01-01

    Rice tungro bacilliform (RTBV) and rice tungro spherical viruses (RTSV) are the two viral components responsible for rice tungro disease which has seriously affected the irrigated rice ecosystem in Southeast Asia for the last 30 years. RTBV has an 8 Kb double-stranded DNA circular genome, and it is primarily responsible for induction of symptoms in infected plants. RTSV has a 12 kb single-stranded RNA genome. It does not induce any apparent symptoms in the infected plant, and it is transmitted by greenleafhopper. RTBV depends upon RTSV for its own transmission. The two viruses are limited to the vascular tissue of the rice plant and are present at a low titer. Most of the detection methods used for the identification of these viruses have relied on the virus protein properties and therefore, early detection of the virus activity was not possible. We were interested in evaluating tissue printing, dot blot, and southern techniques for early detection of virus nucleic acids in rice plant using radioactive and non radioactive probes. 32 P-labeled T7 or SP6 RNA polymerase transcripts complementary to the RTBV genome and RTSV coat protein genes were used as probes of the positive stand of both viruses. For nonradioactive probes, RTBV DNA genome was labeled using the ECL detection kit (Amersham). Preliminary results show that viral nucleic acids of RTBV and RTSV could be detected using both labelling systems. Non radioactive probes were comparable in their sensitivity to the radioactive probes. Less than 100 pg of viral DNA was detected in the dot-blot assays. More data will be presented to compare the efficiency and reliability of these two techniques in detecting early virus activity in the rice plant. (author)

  19. Random and Systematic Errors Share in Total Error of Probes for CNC Machine Tools

    Directory of Open Access Journals (Sweden)

    Adam Wozniak

    2018-03-01

    Full Text Available Probes for CNC machine tools, as every measurement device, have accuracy limited by random errors and by systematic errors. Random errors of these probes are described by a parameter called unidirectional repeatability. Manufacturers of probes for CNC machine tools usually specify only this parameter, while parameters describing systematic errors of the probes, such as pre-travel variation or triggering radius variation, are used rarely. Systematic errors of the probes, linked to the differences in pre-travel values for different measurement directions, can be corrected or compensated, but it is not a widely used procedure. In this paper, the share of systematic errors and random errors in total error of exemplary probes are determined. In the case of simple, kinematic probes, systematic errors are much greater than random errors, so compensation would significantly reduce the probing error. Moreover, it shows that in the case of kinematic probes commonly specified unidirectional repeatability is significantly better than 2D performance. However, in the case of more precise strain-gauge probe systematic errors are of the same order as random errors, which means that errors correction or compensation, in this case, would not yield any significant benefits.

  20. Fabrication, characterization, and functionalization of dual carbon electrodes as probes for scanning electrochemical microscopy (SECM).

    Science.gov (United States)

    McKelvey, Kim; Nadappuram, Binoy Paulose; Actis, Paolo; Takahashi, Yasufumi; Korchev, Yuri E; Matsue, Tomokazu; Robinson, Colin; Unwin, Patrick R

    2013-08-06

    Dual carbon electrodes (DCEs) are quickly, easily, and cheaply fabricated by depositing pyrolytic carbon into a quartz theta nanopipet. The size of DCEs can be controlled by adjusting the pulling parameters used to make the nanopipet. When operated in generation/collection (G/C) mode, the small separation between the electrodes leads to reasonable collection efficiencies of ca. 30%. A three-dimensional finite element method (FEM) simulation is developed to predict the current response of these electrodes as a means of estimating the probe geometry. Voltammetric measurements at individual electrodes combined with generation/collection measurements provide a reasonable guide to the electrode size. DCEs are employed in a scanning electrochemical microscopy (SECM) configuration, and their use for both approach curves and imaging is considered. G/C approach curve measurements are shown to be particularly sensitive to the nature of the substrate, with insulating surfaces leading to enhanced collection efficiencies, whereas conducting surfaces lead to a decrease of collection efficiency. As a proof-of-concept, DCEs are further used to locally generate an artificial electron acceptor and to follow the flux of this species and its reduced form during photosynthesis at isolated thylakoid membranes. In addition, 2-dimensional images of a single thylakoid membrane are reported and analyzed to demonstrate the high sensitivity of G/C measurements to localized surface processes. It is finally shown that individual nanometer-size electrodes can be functionalized through the selective deposition of platinum on one of the two electrodes in a DCE while leaving the other one unmodified. This provides an indication of the future versatility of this type of probe for nanoscale measurements and imaging.

  1. Workshop on the coupling of synchrotron radiation IR and X-rays with tip based scanning probe microscopies X-TIP

    Energy Technology Data Exchange (ETDEWEB)

    Comin, F.; Martinez-Criado, G.; Mundboth, K.; Susini, J. [European Synchrotron Radiation Facility (ESRF), 38 - Grenoble (France); Purans, J.; Sammelselg, V. [Tartu Univ. (Estonia); Chevrier, J.; Huant, S. [Universite Joseph-Fourier, Grenoble I, LEPES, 38 (France); Hamilton, B. [School of Electrical Engineering and Electronics, Manchester (United Kingdom); Saito, A. [Osaka Univ., RIKEN/SPring8 (Japan); Dhez, O. [OGG, INFM/CNR, 38 - Grenoble (France); Brocklesby, W.S. [Southampton Univ., Optoelectronics Research Centre (United Kingdom); Alvarez-Prado, L.M. [Ovieado, Dept. de Fisica (Spain); Kuzmin, A. [Institute of Solid State Physics - Riga (Latvia); Pailharey, D. [CRMC-N - CNRS, 13 - Marseille (France); Tonneau, D. [CRMCN - Faculte des sciences de Luminy, 13 - Marseille (France); Chretien, P. [Laboratoire de Genie Electrique de Paris, 75 - Paris (France); Cricenti, A. [ISM-CNR, Rome (Italy); DeWilde, Y. [ESPCI, 75 - Paris (France)

    2005-07-01

    The coupling of scanning probe microscopy (SPM) with synchrotron radiation is attracting increasing attention from nano-science community. By combining these 2 tools one can visualize, for example, the sample nano-structure prior to any X-ray characterization. Coupled with focusing devices or independently, SPM can provide spatial resolution below the optical limits. Furthermore, the possibility of employing SPM to manipulate nano-objects under X-ray beams is another exciting perspective. This document gathers the transparencies of 6 of the presentations made at the workshop: 1) the combination of atomic force microscopy and X-ray beam - experimental set-up and objectives; 2) the combination of scanning probe microscope and X-rays for detection of electrons; 3) towards soft X-ray scanning microscopy using tapered capillaries and laser-based high harmonic sources; 4) near-field magneto-optical microscopy; 5) near-field scanning optical microscopy - a brief overview -; and 6) from aperture-less near-field optical microscopy to infra-red near-field night vision. 4 posters entitled: 1) development of laboratory setup for X-ray/AFM experiments, 2) towards X-ray diffraction on single islands, 3) nano-XEOL using near-field detection, and 4) local collection with a STM tip of photoelectrons emitted by a surface irradiated by visible of UV laser beam, are included in the document.

  2. Workshop on the coupling of synchrotron radiation IR and X-rays with tip based scanning probe microscopies X-TIP

    International Nuclear Information System (INIS)

    Comin, F.; Martinez-Criado, G.; Mundboth, K.; Susini, J.; Purans, J.; Sammelselg, V.; Chevrier, J.; Huant, S.; Hamilton, B.; Saito, A.; Dhez, O.; Brocklesby, W.S.; Alvarez-Prado, L.M.; Kuzmin, A.; Pailharey, D.; Tonneau, D.; Chretien, P.; Cricenti, A.; DeWilde, Y.

    2005-01-01

    The coupling of scanning probe microscopy (SPM) with synchrotron radiation is attracting increasing attention from nano-science community. By combining these 2 tools one can visualize, for example, the sample nano-structure prior to any X-ray characterization. Coupled with focusing devices or independently, SPM can provide spatial resolution below the optical limits. Furthermore, the possibility of employing SPM to manipulate nano-objects under X-ray beams is another exciting perspective. This document gathers the transparencies of 6 of the presentations made at the workshop: 1) the combination of atomic force microscopy and X-ray beam - experimental set-up and objectives; 2) the combination of scanning probe microscope and X-rays for detection of electrons; 3) towards soft X-ray scanning microscopy using tapered capillaries and laser-based high harmonic sources; 4) near-field magneto-optical microscopy; 5) near-field scanning optical microscopy - a brief overview -; and 6) from aperture-less near-field optical microscopy to infra-red near-field night vision. 4 posters entitled: 1) development of laboratory setup for X-ray/AFM experiments, 2) towards X-ray diffraction on single islands, 3) nano-XEOL using near-field detection, and 4) local collection with a STM tip of photoelectrons emitted by a surface irradiated by visible of UV laser beam, are included in the document

  3. Application of scanning Kelvin probe microscopy for the electrical characterization of microcrystalline silicon for photovoltaics

    International Nuclear Information System (INIS)

    Breymesser, A.

    2000-05-01

    In the last years microcrystalline silicon thin films have attracted great attention as a new photovoltaic material. With this material it is possible to combine simple and cheap low temperature deposition techniques known from amorphous silicon with the long-term stability of the photovoltaic performance like in bulk crystalline silicon solar cells. The critical point is the deposition procedure with numerous tunable parameters influencing the quality and character of the produced diode structures. Additionally there is a great uncertainty about unintentionally incorporated defects, which is not affected by the deposition parameters. Extended investigation of the material, diode and solar cell characteristics is essential in order to correlate the impact of deposition conditions with the quality of the devices. The situation is complicated due to the anisotropic and inhomogeneous character of microcrystalline silicon. Scanning Kelvin probe microscopy (SKPM) is a work function measurement method based on a scanning force microscope (SFM) and a modified Kelvin probe technique. Due to the excellent lateral resolution of the SFM work function measurements with resolutions far below the micrometer level can be carried out. Applied on doped microcrystalline silicon structures it is possible to visualize the position of the Fermi level within the band gap and the influence of the deposition conditions on it. Within this work a SKPM based on a commercially available SFM was constructed and built. Great effort was concentrated on the characterization of the SKPM experiment. On the basis of an extended knowledge about the performance investigations concentrated on cross sections of microcrystalline silicon diode structures produced by hot-wire chemical vapor deposition (HW-CVD). A pin structure for the diodes was chosen due to the low diffusion lengths within this rather defective material. The evolution of the built-in electric drift field within the intrinsic absorber is

  4. Scanning transmission X-ray microscopy as a speciation tool for natural organic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, J.; Plaschke, M.; Denecke, M.A. [Inst. fuer Nukleare Entsorgung, Forschungszentrum Karlsruhe, Karlsruhe (Germany)

    2004-07-01

    A molecular-scale understanding of the basic processes affecting stability and transport behavior of actinide cations, complexes or hydroxide ('eigencolloid') species is prerequisite to performance assessment of nuclear waste disposal in geological formations. Depending on their functional group chemistry and macromolecular structure, naturally occurring organic molecules (NOM) possess a high tendency towards actinide complexation reactions. However, the compositional and structural heterogeneity of NOM and mixed aggregates with inorganic phases makes speciation by spectromicroscopy techniques highly desirable. The applicability of Scanning Transmission X-ray Microscopy (STXM) as a speciation tool for the characterization of NOM is demonstrated for a multifunctional natural organic acid (chlorogenic acid), Eu(III)-loaded humic acid (HA) aggregates and Eu(III)-oxo/hydroxide/HA hetero-aggregates. It is shown that in situ probing of HA functional group chemistry down to a spatial resolution < 100 nm (i.e., less than femto-liter sampled volumes) is feasible, at the same time revealing morphological details on NOM aggregates and NOM/mineral associations. (orig.)

  5. Reverse micelles as a tool for probing solvent modulation of protein dynamics: Reverse micelle encapsulated hemoglobin

    Science.gov (United States)

    Roche, Camille J.; Dantsker, David; Heller, Elizabeth R.; Sabat, Joseph E.; Friedman, Joel M.

    2013-08-01

    Hydration waters impact protein dynamics. Dissecting the interplay between hydration waters and dynamics requires a protein that manifests a broad range of dynamics. Proteins in reverse micelles (RMs) have promise as tools to achieve this objective because the water content can be manipulated. Hemoglobin is an appropriate tool with which to probe hydration effects. We describe both a protocol for hemoglobin encapsulation in reverse micelles and a facile method using PEG and cosolvents to manipulate water content. Hydration properties are probed using the water-sensitive fluorescence from Hb bound pyranine and covalently attached Badan. Protein dynamics are probed through ligand recombination traces derived from photodissociated carbonmonoxy hemoglobin on a log scale that exposes the potential role of both α and β solvent fluctuations in modulating protein dynamics. The results open the possibility of probing hydration level phenomena in this system using a combination of NMR and optical probes.

  6. PREDICTING CHEMICAL REACTIVITY OF HUMIC SUBSTANCES FOR MINERALS AND XENOBIOTICS: USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY AND VIRTUAL REALITY

    Science.gov (United States)

    In this chapter we review the literature on scanning probe microscopy (SPM), virtual reality (VR), and computational chemistry and our earlier work dealing with modeling lignin, lignin-carbohydrate complexes (LCC), humic substances (HSs) and non-bonded organo-mineral interactions...

  7. An inverse method for determining the interaction force between the probe and sample using scanning near-field optical microscopy

    International Nuclear Information System (INIS)

    Chang, Win-Jin; Fang, Te-Hua

    2006-01-01

    This study proposes a means for calculating the interaction force during the scanning process using a scanning near-field optical microscope (SNOM) probe. The determination of the interaction force in the scanning system is regarded as an inverse vibration problem. The conjugate gradient method is applied to treat the inverse problem using available displacement measurements. The results show that the conjugate gradient method is less sensitive to measurement errors and prior information on the functional form of quality was not required. Furthermore, the initial guesses for the interaction force can be arbitrarily chosen for the iteration process

  8. Human MLPA Probe Design (H-MAPD: a probe design tool for both electrophoresis-based and bead-coupled human multiplex ligation-dependent probe amplification assays

    Directory of Open Access Journals (Sweden)

    Hatchwell Eli

    2008-09-01

    Full Text Available Abstract Background Multiplex ligation-dependent probe amplification (MLPA is an efficient and reliable technique for gene dosage analysis. Currently MLPA can be conducted on two platforms: traditional electrophoresis-based, and FlexMAP bead-coupled. Since its introduction in 2002, MLPA has been rapidly adopted in both clinical and research situations. However, MLPA probe design is a time consuming process requiring many steps that address multiple criteria. There exist only one or two commercial software packages for traditional electrophoresis-based MLPA probe design. To our knowledge, no software is yet available that performs bead-coupled MLPA probe design. Results We have developed H-MAPD, a web-based tool that automates the generation and selection of probes for human genomic MLPA. The software performs physical-chemical property tests using UNAFold software, and uniqueness tests using the UCSC genome browser. H-MAPD supports both traditional electrophoresis-based assays, as well as FlexMAP bead-coupled MLPA. Conclusion H-MAPD greatly reduces the efforts for human genomic MLPA probe design. The software is written in Perl-CGI, hosted on a Linux server, and is freely available to non-commercial users.

  9. Dual purpose QA tool developed for teletherapy unit and CT scan in SNDH

    International Nuclear Information System (INIS)

    Shilvant, D.V.; Tamane, C.J.; Pangam, S.B.; Raees, M.D.; Aynoor, S.K.; Pol, P.S.; Verghese, Aju; Ghorpade, C.J.

    2007-01-01

    To make a simple device used in Teletherapy unit and CT scan for depth data measurement. The accurate depth data is essential and very important factor for precise treatment in SAD isocentric setup calculation. In CT scan based treatment planning, the calculation obtained is from the depth given by the CT scan. The success of treatment depends on the same parameters in treatment unit matched with diagnostic CT scan data. To check the depth parameters in both CT scan and Teletherapy unit we have developed a single QA tool in our hospital. As this tool is precise, handy and easily accessible the results obtained from it assures the quality of Teletherapy unit as well as CT scan depth data. This small device resulted data helps a lot in calculations of complicated SAD setup in Telecobalt and also useful in recent new treatment modalities such as IMRT, micro MLC, etc

  10. Using confocal laser scanning microscopy to probe the milk fat globule membrane and associated proteins.

    Science.gov (United States)

    Gallier, Sophie; Gragson, Derek; Jiménez-Flores, Rafael; Everett, David

    2010-04-14

    The bovine milk fat globule membrane (MFGM) is an important, biologically relevant membrane due to its functional and health properties. Its composition has been thoroughly studied, but its structure, especially the lateral organization of its components, still remains unclear. We have used confocal laser scanning microscopy (CLSM) to investigate the surface structure of the MFGM in globules with different degrees of processing using two types of fluorescently labeled phospholipid probes and a protein dye. Using this technique, we have observed heterogeneities in the distribution of MFGM lipids and proteins relating to the processing and size of the globules. The effect of pretreating the milk (centrifugation, pasteurization-homogenization and churning) was studied by double-staining the surface of the milk fat globules, followed by observation using CLSM, and by determining the phospholipid profile of raw milk, raw cream, processed milk and buttermilk powder. Our findings agree with other techniques by showing that the composition of the MFGM changes with processing through the loss of phospholipids and the adsorption of caseins and whey proteins onto the surface.

  11. Sensing the facet orientation in silver nano-plates using scanning Kelvin probe microscopy in air

    Energy Technology Data Exchange (ETDEWEB)

    Abdellatif, M.H. [Department of Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Physics Department, National Research Center, Elbehoos st., 12622, Dokki, Giza (Egypt); Salerno, M., E-mail: marco.salerno@iit.it [Department of Nanophysics, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Polovitsyn, Anatolii [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); Dipartimentodi Fisica, Università di Genova, via Dodecaneso 33, I-16146 Genova (Italy); Marras, Sergio [Department of Nanochemistry, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy); De Angelis, Francesco [Department of Nanostructures, Istituto Italiano di Tecnologia, via Morego 30, I-16163 Genova (Italy)

    2017-05-01

    Highlights: • The surface potential of drop cast nanocrystals was measured by SKPM in ambient air. • The nanocrystal facet work function was derived by theory. • By comparing theory and experiment we distinguished the nanocrystal facets. • Nanocrystal facet control is of practical interest for optoelectronic devices. - Abstract: The work function of nano-materials is important for a full characterization of their electronic properties. Because the band alignment, band bending and electronic noise are very sensitive to work function fluctuations, the dependence of the work function of nano-scale crystals on facet orientation can be a critical issue in optimizing optoelectronic devices based on these materials. We used scanning Kelvin probe microscopy to assess the local work function on samples of silver nano-plates at sub-micrometric spatial resolution. With the appropriate choice of the substrate and based on statistical analysis, it was possible to distinguish the surface potential of the different facets of silver nano-plates even if the measurements were done in ambient conditions without the use of vacuum. A phenomenological model was used to calculate the differences of facet work function of the silver nano-plates and the corresponding shift in Fermi level. This theoretical prediction and the experimentally observed difference in surface potential on the silver nano-plates were in good agreement. Our results show the possibility to sense the nano-crystal facets by appropriate choice of the substrate in ambient conditions.

  12. Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope

    Directory of Open Access Journals (Sweden)

    Matthew F. B. Green

    2014-10-01

    Full Text Available One of the paramount goals in nanotechnology is molecular-scale functional design, which includes arranging molecules into complex structures at will. The first steps towards this goal were made through the invention of the scanning probe microscope (SPM, which put single-atom and single-molecule manipulation into practice for the first time. Extending the controlled manipulation to larger molecules is expected to multiply the potential of engineered nanostructures. Here we report an enhancement of the SPM technique that makes the manipulation of large molecular adsorbates much more effective. By using a commercial motion tracking system, we couple the movements of an operator's hand to the sub-angstrom precise positioning of an SPM tip. Literally moving the tip by hand we write a nanoscale structure in a monolayer of large molecules, thereby showing that our method allows for the successful execution of complex manipulation protocols even when the potential energy surface that governs the interaction behaviour of the manipulated nanoscale object(s is largely unknown.

  13. Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules

    Directory of Open Access Journals (Sweden)

    Philipp Leinen

    2015-11-01

    Full Text Available Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926–1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf of the non-contact atomic force microscope (NC-AFM tuning fork sensor as well as the magnitude of the electric current (I flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111 surface.

  14. Determination of the electrical resistivity of vertically aligned carbon nanotubes by scanning probe microscopy

    Science.gov (United States)

    Ageev, O. A.; Il'in, O. I.; Rubashkina, M. V.; Smirnov, V. A.; Fedotov, A. A.; Tsukanova, O. G.

    2015-07-01

    Techniques are developed to determine the resistance per unit length and the electrical resistivity of vertically aligned carbon nanotubes (VA CNTs) using atomic force microscopy (AFM) and scanning tunneling microscopy (STM). These techniques are used to study the resistance of VA CNTs. The resistance of an individual VA CNT calculated with the AFM-based technique is shown to be higher than the resistance of VA CNTs determined by the STM-based technique by a factor of 200, which is related to the influence of the resistance of the contact of an AFM probe to VA CNTs. The resistance per unit length and the electrical resistivity of an individual VA CNT 118 ± 39 nm in diameter and 2.23 ± 0.37 μm in height that are determined by the STM-based technique are 19.28 ± 3.08 kΩ/μm and 8.32 ± 3.18 × 10-4 Ω m, respectively. The STM-based technique developed to determine the resistance per unit length and the electrical resistivity of VA CNTs can be used to diagnose the electrical parameters of VA CNTs and to create VA CNT-based nanoelectronic elements.

  15. Probing the location of displayed cytochrome b562 on amyloid by scanning tunnelling microscopy

    International Nuclear Information System (INIS)

    Forman, C J; Barker, P D; Wang, N; Durkan, C; Yang, Z Y; Mowat, C G; Jarvis, S

    2013-01-01

    Amyloid fibres displaying cytochrome b 562 were probed using scanning tunnelling microscopy (STM) in vacuo. The cytochromes are electron transfer proteins containing a haem cofactor and could, in principle, mediate electron transfer between the tip and the gold substrate. If the core fibres were insulating and electron transfer within the 3D haem network was detected, then the electron transport properties of the fibre could be controlled by genetic engineering. Three kinds of STM images were obtained. At a low bias ( 562 was not detected by STM, which was attributed to low adhesion, whereas a monomeric multi-haem protein, GSU1996, was readily imaged. We conclude that the fibre superstructure may be intermittently conducting, that the cytochromes have been seen within the fibres and that they are too far apart for detectable current flow between sites to occur. We predict that GSU1996, being 10 nm long, is more likely to mediate successful electron transfer along the fibre as well as being more readily detectable when displayed from amyloid. (paper)

  16. Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules.

    Science.gov (United States)

    Leinen, Philipp; Green, Matthew F B; Esat, Taner; Wagner, Christian; Tautz, F Stefan; Temirov, Ruslan

    2015-01-01

    Controlled manipulation of single molecules is an important step towards the fabrication of single molecule devices and nanoscale molecular machines. Currently, scanning probe microscopy (SPM) is the only technique that facilitates direct imaging and manipulations of nanometer-sized molecular compounds on surfaces. The technique of hand-controlled manipulation (HCM) introduced recently in Beilstein J. Nanotechnol. 2014, 5, 1926-1932 simplifies the identification of successful manipulation protocols in situations when the interaction pattern of the manipulated molecule with its environment is not fully known. Here we present a further technical development that substantially improves the effectiveness of HCM. By adding Oculus Rift virtual reality goggles to our HCM set-up we provide the experimentalist with 3D visual feedback that displays the currently executed trajectory and the position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf) of the non-contact atomic force microscope (NC-AFM) tuning fork sensor as well as the magnitude of the electric current (I) flowing between the tip and the surface. The advantages of the set-up are demonstrated by applying it to the model problem of the extraction of an individual PTCDA molecule from its hydrogen-bonded monolayer grown on Ag(111) surface.

  17. Sensing the facet orientation in silver nano-plates using scanning Kelvin probe microscopy in air

    International Nuclear Information System (INIS)

    Abdellatif, M.H.; Salerno, M.; Polovitsyn, Anatolii; Marras, Sergio; De Angelis, Francesco

    2017-01-01

    Highlights: • The surface potential of drop cast nanocrystals was measured by SKPM in ambient air. • The nanocrystal facet work function was derived by theory. • By comparing theory and experiment we distinguished the nanocrystal facets. • Nanocrystal facet control is of practical interest for optoelectronic devices. - Abstract: The work function of nano-materials is important for a full characterization of their electronic properties. Because the band alignment, band bending and electronic noise are very sensitive to work function fluctuations, the dependence of the work function of nano-scale crystals on facet orientation can be a critical issue in optimizing optoelectronic devices based on these materials. We used scanning Kelvin probe microscopy to assess the local work function on samples of silver nano-plates at sub-micrometric spatial resolution. With the appropriate choice of the substrate and based on statistical analysis, it was possible to distinguish the surface potential of the different facets of silver nano-plates even if the measurements were done in ambient conditions without the use of vacuum. A phenomenological model was used to calculate the differences of facet work function of the silver nano-plates and the corresponding shift in Fermi level. This theoretical prediction and the experimentally observed difference in surface potential on the silver nano-plates were in good agreement. Our results show the possibility to sense the nano-crystal facets by appropriate choice of the substrate in ambient conditions.

  18. Probing Chromatin-modifying Enzymes with Chemical Tools

    KAUST Repository

    Fischle, Wolfgang; Schwarzer, Dirk

    2016-01-01

    and represent promising drug targets in modern medicine. We summarize and discuss recent advances in the field of chemical biology that have provided chromatin research with sophisticated tools for investigating the composition, activity, and target sites

  19. Scanning near-field optical microscopy and near-field optical probes: properties, fabrication, and control of parameters

    International Nuclear Information System (INIS)

    Dryakhlushin, V F; Veiko, V P; Voznesenskii, N B

    2007-01-01

    A brief review of modern applications of scanning near-field optical (SNO) devices in microscopy, spectroscopy, and lithography is presented in the introduction. The problem of the development of SNO probes, as the most important elements of SNO devices determining their resolution and efficiency, is discussed. Based on the works of the authors, two different methods for fabricating SNO probes by using the adiabatic tapering of an optical fibre are considered: the laser-heated mechanical drawing and chemical etching. A nondestructive optical method for controlling the nanometre aperture of SNO probes is proposed, substantiated, and tested experimentally. The method is based on the reconstruction of a near-field source with the help of a theoretical algorithm of the inverse problem from the experimental far-filed intensity distribution. Some prospects for a further refinement of the construction and technology of SNO probes are discussed. (optical microscopy)

  20. The memory effect of nanoscale memristors investigated by conducting scanning probe microscopy methods

    Directory of Open Access Journals (Sweden)

    César Moreno

    2012-11-01

    Full Text Available We report on the use of scanning force microscopy as a versatile tool for the electrical characterization of nanoscale memristors fabricated on ultrathin La0.7Sr0.3MnO3 (LSMO films. Combining conventional conductive imaging and nanoscale lithography, reversible switching between low-resistive (ON and high-resistive (OFF states was locally achieved by applying voltages within the range of a few volts. Retention times of several months were tested for both ON and OFF states. Spectroscopy modes were used to investigate the I–V characteristics of the different resistive states. This permitted the correlation of device rectification (reset with the voltage employed to induce each particular state. Analytical simulations by using a nonlinear dopant drift within a memristor device explain the experimental I–V bipolar cycles.

  1. A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

    Directory of Open Access Journals (Sweden)

    Tobias Meier

    2015-02-01

    Full Text Available We describe an atomic force microscope (AFM for the characterization of self-sensing tunneling magnetoresistive (TMR cantilevers. Furthermore, we achieve a large scan-range with a nested scanner design of two independent piezo scanners: a small high resolution scanner with a scan range of 5 × 5 × 5 μm3 is mounted on a large-area scanner with a scan range of 800 × 800 × 35 μm3. In order to characterize TMR sensors on AFM cantilevers as deflection sensors, the AFM is equipped with a laser beam deflection setup to measure the deflection of the cantilevers independently. The instrument is based on a commercial AFM controller and capable to perform large-area scanning directly without stitching of images. Images obtained on different samples such as calibration standard, optical grating, EPROM chip, self-assembled monolayers and atomic step-edges of gold demonstrate the high stability of the nested scanner design and the performance of self-sensing TMR cantilevers.

  2. Determination of the mechanical behavior of lithium disilicate glass ceramics by nanoindentation and scanning probe microscopy

    International Nuclear Information System (INIS)

    Smith, Calvin M.; Jiang, Danyu; Gong, Jianghong; Yin, Ling

    2014-01-01

    This paper reports on the mechanical behavior of high-strength dental ceramics, lithium disilicate glass ceramics (LDGC) using nanoindentation and in situ scanning probe microscopy (SPM). The nanoindentation hardness and Young's moduli of LDGC were measured as a function of the applied indentation load. The indentation load/size effect (ISE) was analyzed for both measured nanoindentation hardness and Young's moduli. The true hardness, i.e., the load-independent hardness, was determined based on the proportional specimen resistance (PSR) model. Nanoindentation-induced plasticity in LDGC was characterized by in situ SPM imaging of the indented volumes and by measuring pile-up heights of indented cross-sections. The results show that both nanoindentation hardness and Young's modulus are load-dependent following the expended Meyer's law using a power series. At the nanoindentation loads, indented LDGC can be mainly plastically deformed by limiting cracking events. This unusual behavior, for nominally brittle materials, influences the mode of contact damage in applications such as machining, polishing, wear, impact damage and hardness testing for dental restorations. - Highlights: • Both hardness and Young's modulus of LDGC were load-dependent following the expended Meyer's law. • The true hardness of LDGC was determined based on the proportional specimen resistance (PSR) model. • Nanoindentation-induced plasticity in LDGC was characterized by in situ SPM imaging. • At low nanoindentation loads, indented LDGC can be mainly plastically deformed by limiting cracking events

  3. Single ion impact detection and scanning probe aligned ion implantation for quantum bit formation

    International Nuclear Information System (INIS)

    Weis, Christoph D.

    2011-01-01

    Quantum computing and quantum information processing is a promising path to replace classical information processing via conventional computers which are approaching fundamental physical limits. Instead of classical bits, quantum bits (qubits) are utilized for computing operations. Due to quantum mechanical phenomena such as superposition and entanglement, a completely different way of information processing is achieved, enabling enhanced performance for certain problem sets. Various proposals exist on how to realize a quantum bit. Among them are electron or nuclear spins of defect centers in solid state systems. Two such candidates with spin degree of freedom are single donor atoms in silicon and nitrogen vacancy (NV) defect centers in diamond. Both qubit candidates possess extraordinary qualities which makes them promising building blocks. Besides certain advantages, the qubits share the necessity to be placed precisely in their host materials and device structures. A commonly used method is to introduce the donor atoms into the substrate materials via ion implantation. For this, focused ion beam systems can be used, or collimation techniques as in this work. A broad ion beam hits the back of a scanning probe microscope (SPM) cantilever with incorporated apertures. The high resolution imaging capabilities of the SPM allows the non destructive location of device areas and the alignment of the cantilever and thus collimated ion beam spot to the desired implant locations. In this work, this technique is explored, applied and pushed forward to meet necessary precision requirements. The alignment of the ion beam to surface features, which are sensitive to ion impacts and thus act as detectors, is demonstrated. The technique is also used to create NV center arrays in diamond substrates. Further, single ion impacts into silicon device structures are detected which enables deliberate single ion doping.

  4. Standardization in dimensional nanometrology: development of a calibration guideline for Scanning Probe Microscopy

    Science.gov (United States)

    Dziomba, Thorsten; Koenders, Ludger; Wilkening, Günter

    2005-10-01

    The continuing miniaturization in many technologies - among them the optical systems - demands high-resolution measurements with uncertainties in the nanometre-range or even well below. A brief introduction of measurement methods used at the micro- & nanometre scale is therefore given as introduction. While a wide range of these methods are well established for the determination of various physical properties down to the nanometric scale, it is Scanning Probe Microscopy (SPM) that provides a unique direct access to topographic surface features in the size range from atomic diameters to some ten or hundred micrometres. With the increasing use of SPMs as quantitative measurement instruments, the demand for standardized calibration routines also for this type of instruments rises. However, except for a few specially designed set-ups mainly at National Metrology Institutes (e. g. PTB in Germany), measurements made with SPMs usually lack traceability to the metre definition. A number of physical transfer standards have therefore been developed and are already available commercially. While detailed knowledge of the standards' properties is a prerequisite for their practical applicability, the calibration procedure itself deserves careful consideration as well. As there is, up to now, no generally accepted concept how to perform SPM calibrations, guidelines are now being developed on various national and international levels, e. g. VDI/VDE-GMA in Germany and ISO. This papers discusses the draft of an SPM calibration guideline by focusing on several critical practical aspects of SPM calibration. The paper intends to invite the readers to take active part in guideline discussions.

  5. Single ion impact detection and scanning probe aligned ion implantation for quantum bit formation

    Energy Technology Data Exchange (ETDEWEB)

    Weis, Christoph D.

    2011-10-04

    Quantum computing and quantum information processing is a promising path to replace classical information processing via conventional computers which are approaching fundamental physical limits. Instead of classical bits, quantum bits (qubits) are utilized for computing operations. Due to quantum mechanical phenomena such as superposition and entanglement, a completely different way of information processing is achieved, enabling enhanced performance for certain problem sets. Various proposals exist on how to realize a quantum bit. Among them are electron or nuclear spins of defect centers in solid state systems. Two such candidates with spin degree of freedom are single donor atoms in silicon and nitrogen vacancy (NV) defect centers in diamond. Both qubit candidates possess extraordinary qualities which makes them promising building blocks. Besides certain advantages, the qubits share the necessity to be placed precisely in their host materials and device structures. A commonly used method is to introduce the donor atoms into the substrate materials via ion implantation. For this, focused ion beam systems can be used, or collimation techniques as in this work. A broad ion beam hits the back of a scanning probe microscope (SPM) cantilever with incorporated apertures. The high resolution imaging capabilities of the SPM allows the non destructive location of device areas and the alignment of the cantilever and thus collimated ion beam spot to the desired implant locations. In this work, this technique is explored, applied and pushed forward to meet necessary precision requirements. The alignment of the ion beam to surface features, which are sensitive to ion impacts and thus act as detectors, is demonstrated. The technique is also used to create NV center arrays in diamond substrates. Further, single ion impacts into silicon device structures are detected which enables deliberate single ion doping.

  6. Probing the location of displayed cytochrome b562 on amyloid by scanning tunnelling microscopy

    Science.gov (United States)

    Forman, C. J.; Wang, N.; Yang, Z. Y.; Mowat, C. G.; Jarvis, S.; Durkan, C.; Barker, P. D.

    2013-05-01

    Amyloid fibres displaying cytochrome b562 were probed using scanning tunnelling microscopy (STM) in vacuo. The cytochromes are electron transfer proteins containing a haem cofactor and could, in principle, mediate electron transfer between the tip and the gold substrate. If the core fibres were insulating and electron transfer within the 3D haem network was detected, then the electron transport properties of the fibre could be controlled by genetic engineering. Three kinds of STM images were obtained. At a low bias (<1.5 V) the fibres appeared as regions of low conductivity with no evidence of cytochrome mediated electron transfer. At a high bias, stable peaks in tunnelling current were observed for all three fibre species containing haem and one species of fibre that did not contain haem. In images of this kind, some of the current peaks were collinear and spaced around 10 nm apart over ranges longer than 100 nm, but background monomers complicate interpretation. Images of the third kind were rare (1 in 150 fibres); in these, fully conducting structures with the approximate dimensions of fibres were observed, suggesting the possibility of an intermittent conduction mechanism, for which a precedent exists in DNA. To test the conductivity, some fibres were immobilized with sputtered gold, and no evidence of conduction between the grains of gold was seen. In control experiments, a variation of monomeric cytochrome b562 was not detected by STM, which was attributed to low adhesion, whereas a monomeric multi-haem protein, GSU1996, was readily imaged. We conclude that the fibre superstructure may be intermittently conducting, that the cytochromes have been seen within the fibres and that they are too far apart for detectable current flow between sites to occur. We predict that GSU1996, being 10 nm long, is more likely to mediate successful electron transfer along the fibre as well as being more readily detectable when displayed from amyloid.

  7. On the sensitivity of probe-corrected spherical near-field antenna measurements with high-order probes using double phi-step theta-scanning scheme against various measurement uncertainties

    DEFF Research Database (Denmark)

    Laitinen, Tommi; Pivnenko, Sergey; Nielsen, Jeppe Majlund

    2011-01-01

    In this paper, the relatively recently introduced double phi-step theta-scanning scheme and the probe correction technique associated with it is examined against the traditional phi-scanning scheme and the first-order probe correction. The important result of this paper is that the double phi......-step theta-scanning scheme is shown to be clearly less sensitive to the probe misalignment errors compared to the phi-scanning scheme. The two methods show similar sensitivity to noise and channel balance error....

  8. Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

    International Nuclear Information System (INIS)

    Morawski, Ireneusz; Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert

    2015-01-01

    A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations

  9. Combined frequency modulated atomic force microscopy and scanning tunneling microscopy detection for multi-tip scanning probe microscopy applications

    Energy Technology Data Exchange (ETDEWEB)

    Morawski, Ireneusz [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany); Institute of Experimental Physics, University of Wrocław, pl. M. Borna 9, 50-204 Wrocław (Poland); Spiegelberg, Richard; Korte, Stefan; Voigtländer, Bert [Peter Grünberg Institut (PGI-3) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich (Germany)

    2015-12-15

    A method which allows scanning tunneling microscopy (STM) tip biasing independent of the sample bias during frequency modulated atomic force microscopy (AFM) operation is presented. The AFM sensor is supplied by an electronic circuit combining both a frequency shift signal and a tunneling current signal by means of an inductive coupling. This solution enables a control of the tip potential independent of the sample potential. Individual tip biasing is specifically important in order to implement multi-tip STM/AFM applications. An extensional quartz sensor (needle sensor) with a conductive tip is applied to record simultaneously topography and conductivity of the sample. The high resonance frequency of the needle sensor (1 MHz) allows scanning of a large area of the surface being investigated in a reasonably short time. A recipe for the amplitude calibration which is based only on the frequency shift signal and does not require the tip being in contact is presented. Additionally, we show spectral measurements of the mechanical vibration noise of the scanning system used in the investigations.

  10. Analytical procedure for experimental quantification of carrier concentration in semiconductor devices by using electric scanning probe microscopy

    International Nuclear Information System (INIS)

    Fujita, Takaya; Matsumura, Koji; Itoh, Hiroshi; Fujita, Daisuke

    2014-01-01

    Scanning capacitance microscopy (SCM) is based on a contact-mode variant of atomic force microscopy, which is used for imaging two-dimensional carrier (electrons and holes) distributions in semiconductor devices. We introduced a method of quantification of the carrier concentration by experimentally deduced calibration curves, which were prepared for semiconductor materials such as silicon and silicon carbide. The analytical procedure was circulated to research organizations in a round-robin test. The effectiveness of the method was confirmed for practical analysis and for what is expected for industrial pre-standardization from the viewpoint of comparability among users. It was also applied to other electric scanning probe microscopy techniques such as scanning spreading resistance microscopy and scanning nonlinear dielectric microscopy. Their depth profiles of carrier concentration were found to be in good agreement with those characterized by SCM. These results suggest that our proposed method will be compatible with future next-generation microscopy. (paper)

  11. Characterizing nanoscale scanning probes using electron microscopy: A novel fixture and a practical guide

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Tevis D. B., E-mail: tjacobs@pitt.edu [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 3700 O’Hara St., Pittsburgh, Pennsylvania 15208 (United States); Wabiszewski, Graham E.; Goodman, Alexander J.; Carpick, Robert W., E-mail: carpick@seas.upenn.edu [Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 220 S. 33rd St., Philadelphia, Pennsylvania 19104 (United States)

    2016-01-15

    The nanoscale geometry of probe tips used for atomic force microscopy (AFM) measurements determines the lateral resolution, contributes to the strength of the tip-surface interaction, and can be a significant source of uncertainty in the quantitative analysis of results. While inverse imaging of the probe tip has been used successfully to determine probe tip geometry, direct observation of the tip profile using electron microscopy (EM) confers several advantages: it provides direct (rather than indirect) imaging, requires fewer algorithmic parameters, and does not require bringing the tip into contact with a sample. In the past, EM-based observation of the probe tip has been achieved using ad hoc mounting methods that are constrained by low throughput, the risk of contamination, and repeatability issues. We report on a probe fixture designed for use in a commercial transmission electron microscope that enables repeatable mounting of multiple AFM probes as well as a reference grid for beam alignment. This communication describes the design, fabrication, and advantages of this probe fixture, including full technical drawings for machining. Further, best practices are discussed for repeatable, non-destructive probe imaging. Finally, examples of the fixture’s use are described, including characterization of common commercial AFM probes in their out-of-the-box condition.

  12. Microscopic measurement of penetration depth in YBa2Cu3O7-δ thin films by scanning Hall probe microscopy

    International Nuclear Information System (INIS)

    Oral, A.; Bending, S.J.; Humphreys, R.G.; Henini, M.

    1997-01-01

    We have used a low noise scanning Hall probe microscope to measure the penetration depth microscopically in a YBa 2 Cu 3 O 7-δ thin film as a function of temperature. The instrument has high magnetic field (approx. 2.9x10 -8 T Hz -1/2 at 77 K) and spatial resolution (approx. 0.85 μm). Magnetic field profiles of single vortices in the superconducting film have been successfully measured and the microscopic penetration depth of the superconductor has been extracted. We find surprisingly large variations in values of λ for different vortices within the scanning field. (author)

  13. Probing Chromatin-modifying Enzymes with Chemical Tools

    KAUST Repository

    Fischle, Wolfgang

    2016-02-04

    Chromatin is the universal template of genetic information in all eukaryotic organisms. Chemical modifications of the DNA-packaging histone proteins and the DNA bases are crucial signaling events in directing the use and readout of eukaryotic genomes. The enzymes that install and remove these chromatin modifications as well as the proteins that bind these marks govern information that goes beyond the sequence of DNA. Therefore, these so-called epigenetic regulators are intensively studied and represent promising drug targets in modern medicine. We summarize and discuss recent advances in the field of chemical biology that have provided chromatin research with sophisticated tools for investigating the composition, activity, and target sites of chromatin modifying enzymes and reader proteins.

  14. Local secondary-electron emission spectra of graphite and gold surfaces obtained using the Scanning Probe Energy Loss Spectrometer (SPELS)

    International Nuclear Information System (INIS)

    Lawton, J J; Pulisciano, A; Palmer, R E

    2009-01-01

    Secondary-electron emission (SEE) spectra have been obtained with the Scanning Probe Energy Loss Spectrometer at a tip-sample distance of only 50 nm. Such short working distances are required for the best theoretical spatial resolution (<10 nm). The SEE spectra of graphite, obtained as a function of tip bias voltage, are shown to correspond to unoccupied states in the electronic band structure. The SEE spectra of thin gold films demonstrate the capability of identifying (carbonaceous) surface contamination with this technique.

  15. Local secondary-electron emission spectra of graphite and gold surfaces obtained using the Scanning Probe Energy Loss Spectrometer (SPELS)

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, J J; Pulisciano, A; Palmer, R E, E-mail: R.E.Palmer@bham.ac.u [Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2009-11-25

    Secondary-electron emission (SEE) spectra have been obtained with the Scanning Probe Energy Loss Spectrometer at a tip-sample distance of only 50 nm. Such short working distances are required for the best theoretical spatial resolution (<10 nm). The SEE spectra of graphite, obtained as a function of tip bias voltage, are shown to correspond to unoccupied states in the electronic band structure. The SEE spectra of thin gold films demonstrate the capability of identifying (carbonaceous) surface contamination with this technique.

  16. Characterisation of corrosion processes of using electron micro-probe, scanning probe microscopy and synchrotron-generated x-ray fluorescence imaging

    International Nuclear Information System (INIS)

    Neufeld, A.K.; Cole, I.S.; Furman, S.A.; Isaacs, H.S.

    2002-01-01

    Full text: With recent advances in computerized technology, the study of chemical reactions can now be visualized as they occur in real time and has resulted in analytical techniques with orders of magnitude greater sensitivity and resolution. This ability offers the corrosion scientist a unique opportunity to study the processes relevant to degradation science which could only be theoretically considered. Neufeld el al (1,2) have attempted to explain in great detail the mechanism of corrosion initiation of zinc by using X-ray micro-probe, Scanning Kelvin probe, and more recently by using synchrotron-generated X-rays and X-ray fluorescence imaging. New results are presented from the synchrotron studies where the transport of ions in-situ has been investigated. The synthesis of information from the techniques will also be discussed in its relevance to atmospheric corrosion processes. Copyright (2002) Australian Society for Electron Microscopy Inc

  17. Superconducting β-ZrNClx probed by scanning-tunnelling and break-junction spectroscopy

    International Nuclear Information System (INIS)

    Ekino, Toshikazu; Sugimoto, Akira; Gabovich, Alexander M.; Zheng, Zhanfeng; Yamanaka, Shoji

    2013-01-01

    Highlights: •STM/STS combined with break-junction tunnelling spectroscopy (BJTS) on β-ZrNCl. •STM image on the ab plane shows triangular atomic lattice spots with a period of 0.36 nm. •The gap peaks are widely distributed (Δ p–p = 9–28 meV)over the area of 100 nm 2 . •Average gap ratio 2Δ/k B T c ∼ 10 is confirmed by both STS and BJTS. -- Abstract: Superconducting layered compound β-ZrNCl x (x = 0.7) with the critical temperature T c = 13–14 K was investigated by means of scanning tunnelling microscopy/spectroscopy. The single-crystal domain facet of ∼100 μm 2 in the c-axis-oriented polycrystal was used as a probing surface. The STM image at 4.9 K shows triangular atomic lattice spots with the period of ∼0.36 nm, which agrees with the X-ray diffraction measurements. The STS measurements of the local conductance, dI/dV, exhibit broadened gap structures with a substantial distribution of the gap-edge values. Most frequently observed peak-to-peak value of ∼20 mV is remarkably similar to the superconducting gap edge of the isostructural β-HfNCl x with T c = 24 K. Temperature, T, dependence of the dI/dV shows that the gap structure disappears above T c ∼ 13 K. Fitting of the dI/dV curve by the broadened BCS density of states leads to the superconducting gap of 2Δ(4.9 K) = 11–13 meV. This is in accordance with our former break-junction data confirming the intrinsic character of the previously obtained extremely large gap to T c ratio 2Δ(0)/k B T c ≈ 10 (k B is the Boltzmann constant), thereby pointing to the unusual superconducting properties of this compound

  18. Reverse micelles as a tool for probing solvent modulation of protein dynamics: Reverse micelle encapsulated hemoglobin☆

    OpenAIRE

    Roche, Camille J.; Dantsker, David; Heller, Elizabeth R.; Sabat, Joseph E.; Friedman, Joel M.

    2013-01-01

    Hydration waters impact protein dynamics. Dissecting the interplay between hydration waters and dynamics requires a protein that manifests a broad range of dynamics. Proteins in reverse micelles (RMs) have promise as tools to achieve this objective because the water content can be manipulated. Hemoglobin is an appropriate tool with which to probe hydration effects. We describe both a protocol for hemoglobin encapsulation in reverse micelles and a facile method using PEG and cosolvents to mani...

  19. An interactive tool for processing sap flux data from thermal dissipation probes

    Science.gov (United States)

    Andrew C. Oishi; Chelcy F. Miniat

    2016-01-01

    Sap flux sensors are an important tool for estimating tree-level transpiration in forested and urban ecosystems around the world. Thermal dissipation (TD) or Granier-type sap flux probes are among the most commonly used due to their reliability, simplicity, and low cost.

  20. Oxidation of hydrogen-passivated silicon surfaces by scanning near-field optical lithography using uncoated and aluminum-coated fiber probes

    DEFF Research Database (Denmark)

    Madsen, Steen; Bozhevolnyi, Sergey I.; Birkelund, Karen

    1997-01-01

    Optically induced oxidation of hydrogen-passivated silicon surfaces using a scanning near-field optical microscope was achieved with both uncoated and aluminum-coated fiber probes. Line scans on amorphous silicon using uncoated fiber probes display a three-peak profile after etching in potassium...... hydroxide. Numerical simulations of the electromagnetic field around the probe-sample interaction region are used to explain the experimental observations. With an aluminum-coated fiber probe, lines of 35 nm in width were transferred into the amorphous silicon layer. (C) 1997 American Institute of Physics....

  1. Development of a Method for Tool Wear Analysis Using 3D Scanning

    Directory of Open Access Journals (Sweden)

    Hawryluk Marek

    2017-12-01

    Full Text Available The paper deals with evaluation of a 3D scanning method elaborated by the authors, by applying it to the analysis of the wear of forging tools. The 3D scanning method in the first place consists in the application of scanning to the analysis of changes in geometry of a forging tool by way of comparing the images of a worn tool with a CAD model or an image of a new tool. The method was evaluated in the context of the important measurement problems resulting from the extreme conditions present during the industrial hot forging processes. The method was used to evaluate wear of tools with an increasing wear degree, which made it possible to determine the wear characteristics in a function of the number of produced forgings. The following stage was the use it for a direct control of the quality and geometry changes of forging tools (without their disassembly by way of a direct measurement of the geometry of periodically collected forgings (indirect method based on forgings. The final part of the study points to the advantages and disadvantages of the elaborated method as well as the potential directions of its further development.

  2. Distribution Analysis of the Local Critical Temperature and Current Density in YBCO Coated Conductors using Low-temperature Scanning Laser and Hall Probe Microscopy

    International Nuclear Information System (INIS)

    Park, S. K.; Cho, B. R.; Park, H. Y.; Ri, H. C.

    2011-01-01

    Distribution of the local critical temperature and current density in YBCO coated conductors were analyzed using Low-temperature Scanning Laser and Hall Probe Microscopy (LTSLHPM). We prepared YBCO coated conductors of various bridge types to study the spatial distribution of the critical temperature and the current density in single and multi bridges. LTSLHPM system was modified for detailed linescan or two-dimensional scan both scanning laser and scanning Hall probe method simultaneously. We analyzed the local critical temperature of single and multi bridges from series of several linescans of scanning laser microscopy. We also investigated local current density and hysteresis curve of single bridge from experimental results of scanning Hall probe microscopy.

  3. Resolution enhancement of scanning four-point-probe measurements on two-dimensional systems

    DEFF Research Database (Denmark)

    Hansen, Torben Mikael; Stokbro, Kurt; Hansen, Ole

    2003-01-01

    A method to improve the resolution of four-point-probe measurements of two-dimensional (2D) and quasi-2D systems is presented. By mapping the conductance on a dense grid around a target area and postprocessing the data, the resolution can be improved by a factor of approximately 50 to better than 1....../15 of the four-point-probe electrode spacing. The real conductance sheet is simulated by a grid of discrete resistances, which is optimized by means of a standard optimization algorithm, until the simulated voltage-to-current ratios converges with the measurement. The method has been tested against simulated...

  4. Two-color pump-probe laser spectroscopy instrument with picosecond time-resolved electronic delay and extended scan range

    Science.gov (United States)

    Yu, Anchi; Ye, Xiong; Ionascu, Dan; Cao, Wenxiang; Champion, Paul M.

    2005-11-01

    An electronically delayed two-color pump-probe instrument was developed using two synchronized laser systems. The instrument has picosecond time resolution and can perform scans over hundreds of nanoseconds without the beam divergence and walk-off effects that occur using standard spatial delay systems. A unique picosecond Ti :sapphire regenerative amplifier was also constructed without the need for pulse stretching and compressing optics. The picosecond regenerative amplifier has a broad wavelength tuning range, which suggests that it will make a significant contribution to two-color pump-probe experiments. To test this instrument we studied the rotational correlation relaxation of myoglobin (τr=8.2±0.5ns) in water as well as the geminate rebinding kinetics of oxygen to myoglobin (kg1=1.7×1011s-1, kg2=3.4×107s-1). The results are consistent with, and improve upon, previous studies.

  5. Scanning Electrochemical Microscopy as a Tool for the Characterization of Dental Erosion

    Directory of Open Access Journals (Sweden)

    Pollyana S. Castro

    2011-01-01

    Full Text Available When the tooth is exposed to acidic environments, an irreversible loss of dental hard tissue occurs in a process called dental erosion. In this work, the scanning electrochemical microscopy (SECM was used to probe the consumption of protons at the vicinity of a tooth surface with a platinum microelectrode fixed at −0.5 (V versus Ag/AgCl/KCl(sat. SECM approach curves were recorded to assess the extent of diffusion in the solution close to the tooth substrate. SECM images clearly demonstrated that the acid erosion process is very fast at solution pH values in the range between 3 and 4.

  6. Reliable identification of deep sulcal pits: the effects of scan session, scanner, and surface extraction tool.

    Directory of Open Access Journals (Sweden)

    Kiho Im

    Full Text Available Sulcal pit analysis has been providing novel insights into brain function and development. The purpose of this study was to evaluate the reliability of sulcal pit extraction with respect to the effects of scan session, scanner, and surface extraction tool. Five subjects were scanned 4 times at 3 MRI centers and other 5 subjects were scanned 3 times at 2 MRI centers, including 1 test-retest session. Sulcal pits were extracted on the white matter surfaces reconstructed with both Montreal Neurological Institute and Freesurfer pipelines. We estimated similarity of the presence of sulcal pits having a maximum value of 1 and their spatial difference within the same subject. The tests showed high similarity of the sulcal pit presence and low spatial difference. The similarity was more than 0.90 and the spatial difference was less than 1.7 mm in most cases according to different scan sessions or scanners, and more than 0.85 and about 2.0 mm across surface extraction tools. The reliability of sulcal pit extraction was more affected by the image processing-related factors than the scan session or scanner factors. Moreover, the similarity of sulcal pit distribution appeared to be largely influenced by the presence or absence of the sulcal pits on the shallow and small folds. We suggest that our sulcal pit extraction from MRI is highly reliable and could be useful for clinical applications as an imaging biomarker.

  7. Reliable identification of deep sulcal pits: the effects of scan session, scanner, and surface extraction tool.

    Science.gov (United States)

    Im, Kiho; Lee, Jong-Min; Jeon, Seun; Kim, Jong-Heon; Seo, Sang Won; Na, Duk L; Grant, P Ellen

    2013-01-01

    Sulcal pit analysis has been providing novel insights into brain function and development. The purpose of this study was to evaluate the reliability of sulcal pit extraction with respect to the effects of scan session, scanner, and surface extraction tool. Five subjects were scanned 4 times at 3 MRI centers and other 5 subjects were scanned 3 times at 2 MRI centers, including 1 test-retest session. Sulcal pits were extracted on the white matter surfaces reconstructed with both Montreal Neurological Institute and Freesurfer pipelines. We estimated similarity of the presence of sulcal pits having a maximum value of 1 and their spatial difference within the same subject. The tests showed high similarity of the sulcal pit presence and low spatial difference. The similarity was more than 0.90 and the spatial difference was less than 1.7 mm in most cases according to different scan sessions or scanners, and more than 0.85 and about 2.0 mm across surface extraction tools. The reliability of sulcal pit extraction was more affected by the image processing-related factors than the scan session or scanner factors. Moreover, the similarity of sulcal pit distribution appeared to be largely influenced by the presence or absence of the sulcal pits on the shallow and small folds. We suggest that our sulcal pit extraction from MRI is highly reliable and could be useful for clinical applications as an imaging biomarker.

  8. An improved model for the oPtImal Measurement Probes Allocation tool

    Energy Technology Data Exchange (ETDEWEB)

    Sterle, C., E-mail: claudio.sterle@unina.it [Consorzio CREATE/Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy); Neto, A.C. [Fusion for Energy, 08019 Barcelona (Spain); De Tommasi, G. [Consorzio CREATE/Dipartimento di Ingegneria Elettrica e delle Tecnologie dell’Informazione, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy)

    2015-10-15

    Highlights: • The problem of optimally allocating the probes of a diagnostic system is tackled. • The problem is decomposed in two consecutive optimization problems. • Two original ILP models are proposed and sequentially solved to optimality. • The proposed ILP models improve and extend the previous work present in literature. • Real size instances have been optimally solved with very low computation time. - Abstract: The oPtImal Measurement Probes Allocation (PIMPA) tool has been recently proposed in [1] to maximize the reliability of a tokamak diagnostic system against the failure of one or more of the processing nodes. PIMPA is based on the solution of integer linear programming (ILP) problems, and it minimizes the effect of the failure of a data acquisition component. The first formulation of the PIMPA model did not support the concept of individual slots. This work presents an improved ILP model that addresses the above mentioned problem, by taking into account all the individual probes.

  9. An improved model for the oPtImal Measurement Probes Allocation tool

    International Nuclear Information System (INIS)

    Sterle, C.; Neto, A.C.; De Tommasi, G.

    2015-01-01

    Highlights: • The problem of optimally allocating the probes of a diagnostic system is tackled. • The problem is decomposed in two consecutive optimization problems. • Two original ILP models are proposed and sequentially solved to optimality. • The proposed ILP models improve and extend the previous work present in literature. • Real size instances have been optimally solved with very low computation time. - Abstract: The oPtImal Measurement Probes Allocation (PIMPA) tool has been recently proposed in [1] to maximize the reliability of a tokamak diagnostic system against the failure of one or more of the processing nodes. PIMPA is based on the solution of integer linear programming (ILP) problems, and it minimizes the effect of the failure of a data acquisition component. The first formulation of the PIMPA model did not support the concept of individual slots. This work presents an improved ILP model that addresses the above mentioned problem, by taking into account all the individual probes.

  10. Surface polymerization of (3,4-ethylenedioxythiophene) probed by in situ scanning tunneling microscopy on Au(111) in ionic liquids.

    Science.gov (United States)

    Ahmad, Shahzada; Carstens, Timo; Berger, Rüdiger; Butt, Hans-Jürgen; Endres, Frank

    2011-01-01

    The electropolymerization of 3,4-ethylenedioxythiophene (EDOT) to poly(3,4-ethylenedioxythiophene) (PEDOT) was investigated in the air and water-stable ionic liquids 1-hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate [HMIm]FAP and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide [EMIm]TFSA. In situ scanning tunnelling microscopy (STM) results show that the electropolymerization of EDOT in the ionic liquid can be probed on the nanoscale. In contrast to present understanding, it was observed that the EDOT can be oxidised in ionic liquids well below its oxidation potential and the under potential growth of polymer was visualized by in situ STM. These results serve as the first study to confirm the under potential growth of conducting polymers in ionic liquids. Furthermore, ex situ microscopy measurements were performed. Quite a high current of 670 nA was observed on the nanoscale by conductive scanning force microscopy (CSFM).

  11. An electronic probe micro-analyser. A linear scan device; Microanalyseur a sonde electronique. Dispositif de balayage lineaire

    Energy Technology Data Exchange (ETDEWEB)

    Kirianenko, A; Maurice, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1963-07-01

    The Castaing electronic probe micro-analyser makes possible static analysis at successive points. For two years this apparatus has been equipped by its constructor with an automatic device for surface scanning. In order to increase the micro-analyser's efficiency a 'linear' scan device has been incorporated making it possible to obtain semi-quantitative analyses very rapidly. (authors) [French] Le microanalyseur a sonde electronique de Castaing permet l'analyse statique en des points successifs. Depuis deux ans, cet appareil a ete equipe par son constructeur d'un dispositif de balayage automatique 'surface'. Afin d'augmenter l'efficacite du microanalyaeur, on a adapte un dispositif de balayage 'lineaire' qui permet d'obtenir tres rapidement des analyses semi-quantitative. (auteurs)

  12. Software Application Profile: PHESANT: a tool for performing automated phenome scans in UK Biobank.

    Science.gov (United States)

    Millard, Louise A C; Davies, Neil M; Gaunt, Tom R; Davey Smith, George; Tilling, Kate

    2017-10-05

    Epidemiological cohorts typically contain a diverse set of phenotypes such that automation of phenome scans is non-trivial, because they require highly heterogeneous models. For this reason, phenome scans have to date tended to use a smaller homogeneous set of phenotypes that can be analysed in a consistent fashion. We present PHESANT (PHEnome Scan ANalysis Tool), a software package for performing comprehensive phenome scans in UK Biobank. PHESANT tests the association of a specified trait with all continuous, integer and categorical variables in UK Biobank, or a specified subset. PHESANT uses a novel rule-based algorithm to determine how to appropriately test each trait, then performs the analyses and produces plots and summary tables. The PHESANT phenome scan is implemented in R. PHESANT includes a novel Javascript D3.js visualization and accompanying Java code that converts the phenome scan results to the required JavaScript Object Notation (JSON) format. PHESANT is available on GitHub at [https://github.com/MRCIEU/PHESANT]. Git tag v0.5 corresponds to the version presented here. © The Author 2017. Published by Oxford University Press on behalf of the International Epidemiological Association.

  13. Nanobits, Nembranes and Micro Four-Point Probes: Customizable Tools for insitu Manipulation and Characterisation of Nanostructures

    DEFF Research Database (Denmark)

    Bøggild, Peter; Petersen, Dirch Hjorth; Sardan Sukas, Özlem

    2010-01-01

    We present a range of highly adaptable microtools for direct interaction with nanoscale structures; (i) semiautomatic pick-and-place assembly of multiwalled carbon nanotubes onto cantilevers for high-aspect ratio scanning probe microscopy, using electrothermal microgrippers inside a SEM. Topology...... on a cantilever; (ii) scanning micro four point probes allow fast, non- destructive mapping of local electrical properties (sheet resistance and Hall mobility) and hysteresis effects of graphene sheets; (iii) sub 100 nm freestanding devices with wires, heaters, actuators, sensors, resonators and probes were...

  14. Wave Optical Calculation of Probe Size in Low Energy Scanning Electron Microscope

    Czech Academy of Sciences Publication Activity Database

    Radlička, Tomáš

    2015-01-01

    Roč. 21, S4 (2015), s. 212-217 ISSN 1431-9276 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : scanning electron microscope * optical calculation Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.730, year: 2015

  15. Carbon-fiber tips for scanning probe microscopes and molecular electronics experiments

    NARCIS (Netherlands)

    Rubio-Bollinger, G.; Castellanos-Gomez, A.; Bilan, S.; Zotti, L.A.; Arroyo, C.R.; Agraït, N.; Cuevas, J.

    2012-01-01

    We fabricate and characterize carbon-fiber tips for their use in combined scanning tunneling and force microscopy based on piezoelectric quartz tuning fork force sensors. An electrochemical fabrication procedure to etch the tips is used to yield reproducible sub-100-nm apex. We also study electron

  16. Magneto-optical Faraday effect probed in a scanning tunneling microscope

    NARCIS (Netherlands)

    Prins, M.W.J.; Wielen, van der M.C.M.M.; Abraham, D.L.; Kempen, van H.; Kesteren, van H.W.

    1994-01-01

    Semiconductor tips are used as local photodetectors in a scanning tunneling microscope. We demonstrate that this configuration is sensitive to small light intensity variations, as supported by a simple model. The principle is applied to the detection of Faraday ellipticity of a Pt/Co multilayer

  17. Measurement of local critical currents in TFA-MOD processed coated conductors by use of scanning Hall-probe microscopy

    International Nuclear Information System (INIS)

    Shiohara, K.; Higashikawa, K.; Kawaguchi, T.; Inoue, M.; Kiss, T.; Yoshizumi, M.; Izumi, T.

    2011-01-01

    We have investigated 2-dimensional distribution of critical current density. We have measured TFA-MOD processed YBCO coated conductor. We used scanning Hall-probe microscopy. These provided information is useful for fabrication process of coated conductor. We have carried out 2-dimensional (2D) measurement of local critical current in a Trifluoroacetates-Metal Organic Deposition (TFA-MOD) processed YBCO coated conductor using scanning Hall-probe microscopy. Recently, remarkable R and D accomplishments on the fabrication processes of coated conductors have been conducted extensively and reported. The TFA-MOD process has been expected as an attractive process to produce coated conductors with high performance at a low production cost due to a simple process using non-vacuum equipments. On the other hand, enhancement of critical currents and homogenization of the critical current distribution in the coated conductors are definitely very important for practical applications. According to our measurements, we can detect positions and spatial distribution of defects in the conductor. This kind of information will be very helpful for the improvement of the TFA-MOD process and for the design of the conductor intended for practical electric power device applications.

  18. Detection of secondary phases in duplex stainless steel by magnetic force microscopy and scanning Kelvin probe force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Salgado, J. [Instituto Mexicano del Petróleo, Dirección de Investigación y Posgrado, Eje Central Norte Lázaro Cárdenas, No. 152, 07730 D.F., México (Mexico); Domínguez-Aguilar, M.A., E-mail: madoming@imp.mx [Instituto Mexicano del Petróleo, Dirección de Investigación y Posgrado, Eje Central Norte Lázaro Cárdenas, No. 152, 07730 D.F., México (Mexico); Castro-Domínguez, B. [University of Tokyo, Department of Chemical System Engineering, Faculty of Engineering Bldg. 5, 7F 722, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113–8656 (Japan); Hernández-Hernández, P. [Instituto Mexicano del Petróleo, Dirección de Investigación y Posgrado, Eje Central Norte Lázaro Cárdenas, No. 152, 07730 D.F., México (Mexico); Newman, R.C. [University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto M5S 3E5 (Canada)

    2013-12-15

    The secondary phase transformations in a commercial super duplex stainless steel were investigated by micro-chemical analyses and high resolution scanning probe microscopy. Energy dispersive X-ray and electron probe detected ferrite and austenite as well as secondary phases in unetched aged duplex stainless steel type 25Cr-7Ni-3Mo. Volta potential indicated that nitride and sigma appeared more active than ferrite, while secondary austenite and austenite presented a nobler potential. Reversal order in nobility is thought to be attributable to the potential ranking provided by oxide nature diversity as a result of secondary phase surface compositions on steel. After eutectoid transformation, secondary austenite was detected by electron probe microanalysis, whereas atomic force microscopy distinguished this phase from former austenite by image contrast. Magnetic force microscopy revealed a “ghosted” effect on the latter microstructure probably derived from metal memory reminiscence of mechanical polishing at passivity and long range magnetic forces of ferrite phase. - Highlights: • Nobility detection of secondary phases by SKPFM in DSS particles is not a straightforward procedure. • As Volta potential and contrast are not always consistent SKPFM surface oxides is thought played an important role in detection. • AFM distinguished secondary austenite from former austenite by image contrast though SEM required EPMA.

  19. Classification of lymph nodes in computerized tomography scans using extracting tools

    International Nuclear Information System (INIS)

    Alves, Allan F.F.; Pina, Diana R. de; Altemani, Joao M.C.

    2016-01-01

    Lymph node changes in the neck region may be originated by both inflammatory and tumor causes. Diagnostic imaging method such as computed tomography are used to distinguish between these two main causes of lymph nodes alterations. In this work we used feature extracting tools I CT scans such as the average value of pixels, wavelet entropy, skewness and kurtosis to assist the radiologist in diagnosing lymph nodes alterations. The wavelet entropy proved to be the best image characteristic parameter to differentiate between the two groups of patients evaluated in this study. The study of cervical lymph nodes changes by features extraction methods may prove to be an excellent tool to assist in differentiating between infectious / inflammatory and tumor causes in CT scans. (author)

  20. Computer Tool for Automatically Generated 3D Illustration in Real Time from Archaeological Scanned Pieces

    OpenAIRE

    Luis López; Germán Arroyo; Domingo Martín

    2012-01-01

    The graphical documentation process of archaeological pieces requires the active involvement of a professional artist to recreate beautiful illustrations using a wide variety of expressive techniques. Frequently, the artist’s work is limited by the inconvenience of working only with the photographs of the pieces he is going to illustrate. This paper presents a software tool that allows the easy generation of illustrations in real time from 3D scanned models. The developed interface allows the...

  1. Nanoscale magnetic field mapping with a single spin scanning probe magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Rondin, L.; Tetienne, J.-P.; Spinicelli, P.; Roch, J.-F.; Jacques, V. [Laboratoire de Photonique Quantique et Moleculaire, Ecole Normale Superieure de Cachan and CNRS UMR 8537, 94235 Cachan Cedex (France); Dal Savio, C.; Karrai, K. [Attocube systems AG, Koeniginstrasse 11A RGB, Munich 80539 (Germany); Dantelle, G. [Laboratoire de Physique de la Matiere Condensee, Ecole Polytechnique and CNRS UMR 7643, 91128 Palaiseau (France); Thiaville, A.; Rohart, S. [Laboratoire de Physique des Solides, Universite Paris-Sud and CNRS UMR 8502, 91405 Orsay (France)

    2012-04-09

    We demonstrate quantitative magnetic field mapping with nanoscale resolution, by applying a lock-in technique on the electron spin resonance frequency of a single nitrogen-vacancy defect placed at the apex of an atomic force microscope tip. In addition, we report an all-optical magnetic imaging technique which is sensitive to large off-axis magnetic fields, thus extending the operation range of diamond-based magnetometry. Both techniques are illustrated by using a magnetic hard disk as a test sample. Owing to the non-perturbing and quantitative nature of the magnetic probe, this work should open up numerous perspectives in nanomagnetism and spintronics.

  2. Surface topography acquisition method for double-sided near-right-angle structured surfaces based on dual-probe wavelength scanning interferometry.

    Science.gov (United States)

    Zhang, Tao; Gao, Feng; Jiang, Xiangqian

    2017-10-02

    This paper proposes an approach to measure double-sided near-right-angle structured surfaces based on dual-probe wavelength scanning interferometry (DPWSI). The principle and mathematical model is discussed and the measurement system is calibrated with a combination of standard step-height samples for both probes vertical calibrations and a specially designed calibration artefact for building up the space coordinate relationship of the dual-probe measurement system. The topography of the specially designed artefact is acquired by combining the measurement results with white light scanning interferometer (WLSI) and scanning electron microscope (SEM) for reference. The relative location of the two probes is then determined with 3D registration algorithm. Experimental validation of the approach is provided and the results show that the method is able to measure double-sided near-right-angle structured surfaces with nanometer vertical resolution and micrometer lateral resolution.

  3. In Silico PCR Tools for a Fast Primer, Probe, and Advanced Searching.

    Science.gov (United States)

    Kalendar, Ruslan; Muterko, Alexandr; Shamekova, Malika; Zhambakin, Kabyl

    2017-01-01

    The polymerase chain reaction (PCR) is fundamental to molecular biology and is the most important practical molecular technique for the research laboratory. The principle of this technique has been further used and applied in plenty of other simple or complex nucleic acid amplification technologies (NAAT). In parallel to laboratory "wet bench" experiments for nucleic acid amplification technologies, in silico or virtual (bioinformatics) approaches have been developed, among which in silico PCR analysis. In silico NAAT analysis is a useful and efficient complementary method to ensure the specificity of primers or probes for an extensive range of PCR applications from homology gene discovery, molecular diagnosis, DNA fingerprinting, and repeat searching. Predicting sensitivity and specificity of primers and probes requires a search to determine whether they match a database with an optimal number of mismatches, similarity, and stability. In the development of in silico bioinformatics tools for nucleic acid amplification technologies, the prospects for the development of new NAAT or similar approaches should be taken into account, including forward-looking and comprehensive analysis that is not limited to only one PCR technique variant. The software FastPCR and the online Java web tool are integrated tools for in silico PCR of linear and circular DNA, multiple primer or probe searches in large or small databases and for advanced search. These tools are suitable for processing of batch files that are essential for automation when working with large amounts of data. The FastPCR software is available for download at http://primerdigital.com/fastpcr.html and the online Java version at http://primerdigital.com/tools/pcr.html .

  4. Scanning electrochemical microscopy determination of hydrogen flux at liquid|liquid interface with potentiometric probe

    OpenAIRE

    Jedraszko, Justyna; Nogala, Wojciech; Adamiak, Wojciech; Girault, Hubert H.; Opallo, Marcin

    2014-01-01

    Scanning electrochemical microscopy potentiometric determination of local hydrogen concentration and its flux next to the liquid|liquid interface was demonstrated. This method is based on the shift of open circuit potential of Pt-based reversible hydrogen electrode. The detection system was verified with a system generating hydrogen under galvanostatic conditions. Then, it was applied to aqueous|1,2-dichloroethane interface where hydrogen is produced with decamethylferrocene as electron donor.

  5. Note: A scanning electron microscope sample holder for bidirectional characterization of atomic force microscope probe tips

    Energy Technology Data Exchange (ETDEWEB)

    Eisenstein, Alon; Goh, M. Cynthia [Department of Chemistry and Institute for Optical Sciences, University of Toronto, 80 St. George Street, Toronto M5S 3H6 (Canada)

    2012-03-15

    A novel sample holder that enables atomic force microscopy (AFM) tips to be mounted inside a scanning electron microscopy (SEM) for the purpose of characterizing the AFM tips is described. The holder provides quick and easy handling of tips by using a spring clip to hold them in place. The holder can accommodate two tips simultaneously in two perpendicular orientations, allowing both top and side view imaging of the tips by the SEM.

  6. Measurement of in-plane magnetic relaxation in RE-123 coated conductors by use of scanning Hall probe microscopy

    International Nuclear Information System (INIS)

    Shiohara, K.; Higashikawa, K.; Inoue, M.; Kiss, T.; Iijima, Y.; Saitoh, T.; Yoshizumi, M.; Izumi, T.

    2013-01-01

    Highlights: ► We have investigated electric field criterion of in-plane critical current density. ► We could measure magnetic relaxation in a remanent state. ► The SHPM results show good agreement with the measurements by the 4-probe method. -- Abstract: We have investigated electric field criterion of in-plane critical current density in a coated conductor characterized by scanning Hall-probe microscopy (SHPM). From remanent field distribution and its relaxation measurements, we could obtain critical current distribution and induced electric field simultaneously by considering the Biot-Savart law and the Faraday’s law, respectively. These results lead us to evaluate a distribution of local critical current density and the corresponding criterion of electric field. As a result, it was found that the electric field criterion for the SHPM analysis was several orders lower than that used in the conventional 4-probe resistive method. However, the data point obtained by the SHPM shows good agreement with E–J curve analytically extended from the measurements by the 4-probe method. This means that we could characterize in-plane distribution of critical current density in a coated conductor at an electric field criterion quantitatively by this method in a nondestructive manner. These findings will be very important information since the uniformity of local critical current density in a coated conductor at extremely low electric fields is a key issue (1) especially for DC applications, (2) for quality control of coated conductors, and (3) for the standardization of the characterization of critical current among different methods

  7. Automated patterning and probing with multiple nanoscale tools for single-cell analysis.

    Science.gov (United States)

    Li, Jiayao; Kim, Yeonuk; Liu, Boyin; Qin, Ruwen; Li, Jian; Fu, Jing

    2017-10-01

    The nano-manipulation approach that combines Focused Ion Beam (FIB) milling and various imaging and probing techniques enables researchers to investigate the cellular structures in three dimensions. Such fusion approach, however, requires extensive effort on locating and examining randomly-distributed targets due to limited Field of View (FOV) when high magnification is desired. In the present study, we present the development that automates 'pattern and probe' particularly for single-cell analysis, achieved by computer aided tools including feature recognition and geometric planning algorithms. Scheduling of serial FOVs for imaging and probing of multiple cells was considered as a rectangle covering problem, and optimal or near-optimal solutions were obtained with the heuristics developed. FIB milling was then employed automatically followed by downstream analysis using Atomic Force Microscopy (AFM) to probe the cellular interior. Our strategy was applied to examine bacterial cells (Klebsiella pneumoniae) and achieved high efficiency with limited human interference. The developed algorithms can be easily adapted and integrated with different imaging platforms towards high-throughput imaging analysis of single cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Spin-polarized scanning-tunneling probe for helical Luttinger liquids.

    Science.gov (United States)

    Das, Sourin; Rao, Sumathi

    2011-06-10

    We propose a three-terminal spin-polarized STM setup for probing the helical nature of the Luttinger liquid edge state that appears in the quantum spin Hall system. We show that the three-terminal tunneling conductance depends on the angle (θ) between the magnetization direction of the tip and the local orientation of the electron spin on the edge while the two terminal conductance is independent of this angle. We demonstrate that chiral injection of an electron into the helical Luttinger liquid (when θ is zero or π) is associated with fractionalization of the spin of the injected electron in addition to the fractionalization of its charge. We also point out a spin current amplification effect induced by the spin fractionalization.

  9. Two-step controllable electrochemical etching of tungsten scanning probe microscopy tips

    KAUST Repository

    Khan, Yasser; Al-Falih, Hisham; Ng, Tien Khee; Ooi, Boon S.; Zhang, Yaping

    2012-01-01

    Dynamic electrochemical etching technique is optimized to produce tungsten tips with controllable shape and radius of curvature of less than 10 nm. Nascent features such as dynamic electrochemical etching and reverse biasing after drop-off are utilized, and two-step dynamic electrochemical etching is introduced to produce extremely sharp tips with controllable aspect ratio. Electronic current shut-off time for conventional dc drop-off technique is reduced to ?36 ns using high speed analog electronics. Undesirable variability in tip shape, which is innate to static dc electrochemical etching, is mitigated with novel dynamic electrochemical etching. Overall, we present a facile and robust approach, whereby using a novel etchant level adjustment mechanism, 30° variability in cone angle and 1.5 mm controllability in cone length were achieved, while routinely producing ultra-sharp probes. © 2012 American Institute of Physics.

  10. Probing the atomic structure of metallic nanoclusters with the tip of a scanning tunneling microscope.

    Science.gov (United States)

    Schouteden, Koen; Lauwaet, Koen; Janssens, Ewald; Barcaro, Giovanni; Fortunelli, Alessandro; Van Haesendonck, Chris; Lievens, Peter

    2014-02-21

    Preformed Co clusters with an average diameter of 2.5 nm are produced in the gas phase and are deposited under controlled ultra-high vacuum conditions onto a thin insulating NaCl film on Au(111). Relying on a combined experimental and theoretical investigation, we demonstrate visualization of the three-dimensional atomic structure of the Co clusters by high-resolution scanning tunneling microscopy (STM) using a Cl functionalized STM tip that can be obtained on the NaCl surface. More generally, use of a functionalized STM tip may allow for systematic atomic structure determination with STM of nanoparticles that are deposited on metal surfaces.

  11. Energy gap and surface structure of superconducting diamond films probed by scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Nishizaki, Terukazu; Takano, Yoshihiko; Nagao, Masanori; Takenouchi, Tomohiro; Kawarada, Hiroshi; Kobayashi, Norio

    2007-01-01

    We have performed scanning tunneling microscopy/spectroscopy (STM/STS) experiments on (1 1 1)-oriented epitaxial films of heavily boron-doped diamond at T = 0.47 K. The STM topography shows two kinds of atomic structures: a hydrogenated 1 x 1 structure, C(1 1 1)1 x 1:H, and an amorphous structure. On the C(1 1 1)1 x 1:H region, the tunneling spectra show superconducting property with the energy gap Δ = 0.83 meV. The obtained gap ratio 2Δ/k B T c = 3.57 is consistent with the weak-coupling BCS theory

  12. The development of synchrotron-assisted scanning probe microscopy at NSRRC

    International Nuclear Information System (INIS)

    Chan, Yuet-Loy; Lu, Dah-An; Hsu, Yao-Jane; Wei, D H; Liang, Xihui; Luo, Meng-Fan; Wu, Tsung-Hsuan

    2013-01-01

    Synchrotron-based X-ray microspectroscopy is a technique that brings together microscopy and X-ray spectroscopy. It can be considered as an experimental approach capable of extracting X-ray spectrum from a finite area, or an alternative way of constructing images with spectroscopic contrast. The goal of this project is to integrate the functions of scanning tunnelling electron microscope (STM) with near edge X-ray absorption fine structure (NEXAFS) spectroscopy. Here, we describe our experimental setup, followed by recent results that demonstrate the feasibility of acquiring NEXAFS spectrum with a SiO 2 coated STM tip

  13. Reversal of atomic contrast in scanning probe microscopy on (111) metal surfaces

    Czech Academy of Sciences Publication Activity Database

    Ondráček, Martin; González, C.; Jelínek, Pavel

    2012-01-01

    Roč. 24, 08 (2012), 084003/1-084003/7 ISSN 0953-8984 R&D Projects: GA ČR(CZ) GPP204/11/P578; GA ČR GAP204/10/0952; GA ČR GA202/09/0545; GA MŠk(CZ) ME10076 Grant - others:AVČR(CZ) M100100904 Institutional research plan: CEZ:AV0Z10100521 Keywords : atomic force microscopy * metallic surfaces * atomic contrast * scanning tunneling microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.355, year: 2012 http://iopscience.iop.org/0953-8984/24/8/084003

  14. Probing defect states in polycrystalline GaN grown on Si(111) by sub-bandgap laser-excited scanning tunneling spectroscopy

    Science.gov (United States)

    Hsiao, F.-M.; Schnedler, M.; Portz, V.; Huang, Y.-C.; Huang, B.-C.; Shih, M.-C.; Chang, C.-W.; Tu, L.-W.; Eisele, H.; Dunin-Borkowski, R. E.; Ebert, Ph.; Chiu, Y.-P.

    2017-01-01

    We demonstrate the potential of sub-bandgap laser-excited cross-sectional scanning tunneling microscopy and spectroscopy to investigate the presence of defect states in semiconductors. The characterization method is illustrated on GaN layers grown on Si(111) substrates without intentional buffer layers. According to high-resolution transmission electron microscopy and cathodoluminescence spectroscopy, the GaN layers consist of nanoscale wurtzite and zincblende crystallites with varying crystal orientations and hence contain high defect state densities. In order to discriminate between band-to-band excitation and defect state excitations, we use sub-bandgap laser excitation. We probe a clear increase in the tunnel current at positive sample voltages during sub-bandgap laser illumination for the GaN layer with high defect density, but no effect is found for high quality GaN epitaxial layers. This demonstrates the excitation of free charge carriers at defect states. Thus, sub-bandgap laser-excited scanning tunneling spectroscopy is a powerful complimentary characterization tool for defect states.

  15. Three-dimensional analysis of micro- and nanostructure of biomaterials and cells by method of scanning probe nanotomography

    Directory of Open Access Journals (Sweden)

    A. E. Efimov

    2017-01-01

    Full Text Available Aim: to perform a three-dimensional analysis of micro- and nanosctucture and quantitative morphological parameters of alginate spherical microcarriers and porous regenerated silk macrocarriers modifi ed by microparticles of decellularized rat liver matrix and human hepatoma HepG2 cells adhered to micro- and macro carriers. Materials and methods. Three-dimensional porous matrices made from regenerated silk by salt leaching technique and alginate spherical microcarriers fabricated by encapsulation were vitalized by human hepatome HepG2 cells. Study of three-dimensional structure of cells and micro- and macro carriers was carried out at –120 °С by scanning probe cryonanotomography technique with use of experimental setup combining cryoultramicrotome and scanning probe microscope.Results. Three-dimensional nanotomographical reconstructions of HepG2 cells adhered to macropore wall of regenerated silk macrocarrier and to spherical alginate microcarrier are obtained. Morphological parameters (mean roughness, effective surface area and autocorrelation length are determined for surfaces of macro and microcarriers and adhered cells. The determined mean roughness of alginate microcarrier surface is 76.4 ± 7.5 nm, while that of surface of macropore wall of regenerated silk macrocarrier is 133.8 ± 16.2 nm. At the same time mean roughness of cells adhered to micro- and macrocarriers are 118.5 ± 9.0 и 158.8 ± 21.6 nm correspondingly. Three-dimensional reconstructions of intracellular compartments with dimensions from 140 to 500 nm are also obtained.Conclusion. Obtained as a result of study quantitative morphology characteristics of surfaces of cell carriers and adhered cells show signifi cant degree of correlation of morphological parameters of cells and their carriers. Use of scanning probe cryonanotomography technique for three-dimensional analysis of structure and characteristics of biomaterials, cells and bio-artifi cial cellular systems

  16. Probing Single Nanometer-scale Particles with Scanning Tunneling Microscopy and Spectroscopies

    International Nuclear Information System (INIS)

    McCarty, G.S.; Love, J.C.; Kushmerick, J.G.; Charles, L.F.; Keating, C.D.; Toleno, B.J.; Lyn, M.E.; Castleman, A.W.; Natan, M.J.; Weiss, P.S.

    1999-01-01

    Scanning tunneling microscopy can be used to isolate single particles on surfaces for further study. Local optical and electronic properties coupled with topographic information collected by the scanning tunneling microscope (STM) give insight into the intrinsic properties of the species under study. Since each spectroscopic measurement is done on a single particle, each sample is 'monodisperse', regardless of the degree of heterogeneity of the original preparation. We illustrate this with three example systems - a metal cluster of known atomic structure, metal nanoparticles dispersed from colloid suspensions, and metallocarbohedrenes (Met-Cars) deposited with other reaction products. Au and Ag nanoparticles were imaged using a photon emission STM. The threshold voltage, the lowest bias voltage at which photons are produced, was determined for Au nanoparticles. Electronic spectra of small clusters of Ni atoms on MoS 2 were recorded. Preliminary images of Zr-based Met-Car-containing soot were obtained on Au and MoS 2 substrates and partial electronic spectra were recorded of these possible Met-Car particles

  17. Development of hole inspection program using touch trigger probe on CNC machine tools

    International Nuclear Information System (INIS)

    Lee, Chan Ho; Lee, Eung Suk

    2012-01-01

    According to many customers' requests, optical measurement module (OMM) applications using automatic measuring devices to measure the machined part rapidly on a machine tool have increased steeply. Touch trigger probes are being used for job setup and feature inspection as automatic measuring devices, and this makes quality checking and machining compensation possible. Therefore, in this study, the use of touch trigger probes for accurate measurement of the machined part has been studied and a macro program for a hole measuring cycle has been developed. This hole is the most common feature to be measured, but conventional methods are still not free from measuring error. In addition, the eccentricity change of the least square circle was simulated according to the roundness error in a hole measurement. To evaluate the reliability of this study, the developed hole measuring program was executed to measure the hole plate on the machine and verify the roundness error in the eccentricity simulation result

  18. Probing the recreational home –The cultural probe as a communicative tool for researcher and user

    OpenAIRE

    Kristav, Per

    2005-01-01

    How can qualitative, ethnographic and emotional aspects from probe users be mapped at the same time as they get something meaningful in return? The emphasis is here on intellectual rewards during probe work rather than future good designs that in a long term perspective can be beneficial for the probe user. This case study has elaborated the traditional use of cultural probes [1] with a selection of ten families with small children in the Öresund region. The idea was to evoke thoughts abou...

  19. T-scan III system diagnostic tool for digital occlusal analysis in orthodontics - a modern approach.

    Science.gov (United States)

    Trpevska, Vesna; Kovacevska, Gordana; Benedeti, Alberto; Jordanov, Bozidar

    2014-01-01

    This systematic literature review was performed to establish the mechanism, methodology, characteristics, clinical application and opportunities of the T-Scan III System as a diagnostic tool for digital occlusal analysis in different fields of dentistry, precisely in orthodontics. Searching of electronic databases, using MEDLINE and PubMed, hand searching of relevant key journals, and screening of reference lists of included studies with no language restriction was performed. Publications providing statistically examined data were included for systematic review. Twenty potentially relevant Randomized Controlled Trials (RCTs) were identified. Only ten met the inclusion criteria. The literature demonstrates that using digital occlusal analysis with T-Scan III System in orthodontics has significant advantage with regard to the capability of measuring occlusal parameters in static positions and during dynamic of the mandible. Within the scope of this systematic review, there is evidence to support that T-Scan system is rapid and accurate in identifying the distribution of the tooth contacts and it shows great promise as a clinical diagnostic screening device for occlusion and for improving the occlusion after various dental treatments. Additional clinical studies are required to advance the indication filed of this system. Importance of using digital occlusal T-Scan analysis in orthodontics deserves further investigation.

  20. A study on the initiation of pitting corrosion in carbon steel in chloride-containing media using scanning electrochemical probes

    International Nuclear Information System (INIS)

    Lin Bin; Hu Ronggang; Ye Chenqing; Li Yan; Lin Changjian

    2010-01-01

    Scanning electrochemical probes of corrosion potential and chloride ions were developed for the in situ monitoring of localized corrosion processes of reinforcing steel in NaCl-containing solution. The results indicated that the chloride ions (Cl - ) preferentially adsorbed and accumulated at the imperfect/defective sites, resulting in initiation and propagation of pitting corrosion on the reinforcing steel surface. An electron microprobe analyzer (EMPA) was used to examine the corrosion morphology and elemental distribution at the corroded location to investigate the origins of the preferential Cl - adsorption and pitting corrosion. By combining the in situ and ex situ images, we concluded that manganese sulfide inclusions in reinforcing steel are the most susceptible defects to pitting corrosion in chloride-containing solution.

  1. Ultrafast photoinduced carrier dynamics in GaNAs probed using femtosecond time-resolved scanning tunnelling microscopy

    International Nuclear Information System (INIS)

    Terada, Yasuhiko; Aoyama, Masahiro; Kondo, Hiroyuki; Taninaka, Atsushi; Takeuchi, Osamu; Shigekawa, Hidemi

    2007-01-01

    The combination of scanning tunnelling microscopy (STM) with optical excitation using ultrashort laser pulses enables us, in principle, to simultaneously obtain ultimate spatial and temporal resolutions. We have developed the shaken-pulse-pair-excited STM (SPPX-STM) and succeeded in detecting a weak time-resolved tunnelling current signal from a low-temperature-grown GaNAs sample. To clarify the underlying physics in SPPX-STM measurements, we performed optical pump-probe reflectivity measurements with a wavelength-changeable ultrashort-pulse laser. By comparing the results obtained from the two methods with an analysis based on the nonlinear relationship between the photocarrier density and tunnelling current, we obtained a comprehensive explanation that the photocarrier dynamics is reflected in the SPPX-STM signal through the surface photovoltage effect

  2. Narrow, highly P-doped, planar wires in silicon created by scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ruess, F J [Australian Research Council Centre of Excellence for Quantum Computer Technology, University of New South Wales, Sydney, NSW 2052 (Australia); Goh, K E J [Australian Research Council Centre of Excellence for Quantum Computer Technology, University of New South Wales, Sydney, NSW 2052 (Australia); Butcher, M J [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Reusch, T C G [Australian Research Council Centre of Excellence for Quantum Computer Technology, University of New South Wales, Sydney, NSW 2052 (Australia); Oberbeck, L [Australian Research Council Centre of Excellence for Quantum Computer Technology, University of New South Wales, Sydney, NSW 2052 (Australia); Weber, B [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Hamilton, A R [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Simmons, M Y [Australian Research Council Centre of Excellence for Quantum Computer Technology, University of New South Wales, Sydney, NSW 2052 (Australia)

    2007-01-31

    We demonstrate the use of a scanning tunnelling microscope (STM) to pattern buried, highly planar phosphorus-doped silicon wires with widths down to the sub-10 nm level. We confirm the structural integrity of these wires using both buried dopant imaging techniques and ex situ electrical characterization. Four terminal I-V characteristics at 4 K show ohmic behaviour for all wires with resistivities between 1 and 24 x 10{sup -8} {omega} cm. Magnetotransport measurements reveal that conduction is dominated by disordered scattering with quantum corrections consistent with 2D weak localization theory. Our results show that these quantum corrections become more pronounced as the electron phase coherence length approaches the width of the wire.

  3. Quantum nature of protons in water probed by scanning tunneling microscopy and spectroscopy

    Science.gov (United States)

    Guo, Jing; Lü, Jing-Tao; Feng, Yexin; Chen, Ji; Peng, Jinbo; Lin, Zeren; Meng, Xiangzhi; Wang, Zhichang; Li, Xin-Zheng; Wang, En-Ge; Jiang, Ying; Jing-Tao Lü Team; Xin-Zheng Li Team

    The complexity of hydrogen-bonding interaction largely arises from the quantum nature of light hydrogen nuclei, which has remained elusive for decades. Here we report the direct assessment of nuclear quantum effects on the strength of a single hydrogen bond formed at a water-salt interface, using tip-enhanced inelastic electron tunneling spectroscopy (IETS) based on a low-temperature scanning tunneling microscope (STM). The IETS signals are resonantly enhanced by gating the frontier orbitals of water via a chlorine-terminated STM tip, such that the hydrogen-bonding strength can be determined with unprecedentedly high accuracy from the redshift in the O-H stretching frequency of water. Isotopic substitution experiments combined with quantum simulations reveal that the anharmonic quantum fluctuations of hydrogen nuclei weaken the weak hydrogen bonds and strengthen the relatively strong ones. However, this trend can be completely reversed when the hydrogen bond is strongly coupled to the polar atomic sites of the surface.

  4. Simultaneously measured signals in scanning probe microscopy with a needle sensor: frequency shift and tunneling current.

    Science.gov (United States)

    Morawski, Ireneusz; Voigtländer, Bert

    2010-03-01

    We present combined noncontact scanning force microscopy and tunneling current images of a platinum(111) surface obtained by means of a 1 MHz quartz needle sensor. The low-frequency circuit of the tunneling current was combined with a high-frequency signal of the quartz resonator enabling full electrical operation of the sensor. The frequency shift and the tunneling current were detected simultaneously, while the feedback control loop of the topography signal was fed using one of them. In both cases, the free signal that was not connected to the feedback loop reveals proportional-integral controller errorlike behavior, which is governed by the time derivative of the topography signal. A procedure is proposed for determining the mechanical oscillation amplitude by utilizing the tunneling current also including the average tip-sample work function.

  5. GMR-based eddy current probe for weld seam inspection and its non-scanning detection study

    Science.gov (United States)

    Gao, Peng; Wang, Chao; Li, Yang; Wang, Libin; Cong, Zheng; Zhi, Ya

    2017-04-01

    Eddy current testing is one of the most important non-destructive testing methods for welding defects detection. This paper presents the use of a probe consisting of 4 giant magneto-resistive (GMR) sensors to detect weld defects. Information from four measuring points above and on both sides of the weld seam is collected at the same time. By setting the GMR sensors' sensing axes perpendicular to the direction of the excitation magnetic field, the information collected mainly reflects the change in the eddy current which is caused by defects. Digital demodulation technology is applied to extract the real part and imaginary part of the GMR sensors' output signals. The variables containing directional information of the magnetic field are introduced. Based on the data from the four GMR (4-GMR) sensors' output signals, four values, Ran, Mean, Var and k are selected as the feature quantities for defect recognition. Experiments are carried out on weld seams with and without defects, and the detection outputs are given in this paper. The 4-GMR probe is also employed to investigate non-scanning weld defect detection and the four feature quantities (Ran, Mean, Var and k) are studied to evaluate weld quality. The non-scanning weld defect detection is presented. A support vector machine is used to classify and discriminate welds with and without defects. Experiments carried out show that through the method in this paper, the recognition rate is 92% for welds without defects and 90% for welds with defects, with an overall recognition rate of 90.9%, indicating that this method could effectively detect weld defects.

  6. PWMScan: a fast tool for scanning entire genomes with a position-specific weight matrix.

    Science.gov (United States)

    Ambrosini, Giovanna; Groux, Romain; Bucher, Philipp

    2018-03-05

    Transcription factors (TFs) regulate gene expression by binding to specific short DNA sequences of 5 to 20-bp to regulate the rate of transcription of genetic information from DNA to messenger RNA. We present PWMScan, a fast web-based tool to scan server-resident genomes for matches to a user-supplied PWM or TF binding site model from a public database. The web server and source code are available at http://ccg.vital-it.ch/pwmscan and https://sourceforge.net/projects/pwmscan, respectively. giovanna.ambrosini@epfl.ch. SUPPLEMENTARY DATA ARE AVAILABLE AT BIOINFORMATICS ONLINE.

  7. Probing odd-triplet contributions to the long-ranged proximity effect by scanning tunneling spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Diesch, Simon; Machon, Peter; Belzig, Wolfgang; Scheer, Elke [Universitaet Konstanz, Konstanz (Germany); Suergers, Christoph; Beckmann, Detlef [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2015-07-01

    In conventional superconductors, electrons are bound in singlet Cooper pairs, i.e. with opposite spin. More recently, experiments on superconductor-ferromagnet-systems have shown Cooper pairs tunneling through ferromagnetic layers, indicating Cooper pairs of equal spin, thus corresponding to a long-range triplet proximity effect. Most experimental evidence for triplet superconductivity comes from observations of the thickness dependence of the Josephson current through a ferromagnetic barrier, but there is an increasing interest in obtaining direct spectroscopic evidence. This project aims at analyzing the electronic density of states of a thin diffusive normal metal layer (Ag) coupled to a superconductor (Al) across a ferromagnetic insulator (EuS) using a scanning tunneling microscope in spectroscopy mode at 280 mK. For this purpose, we fabricated EuS films of different thicknesses and acquired spectroscopic data at different magnetic fields. We observe significant broadening of the superconductive energy gap and a variety of sub-gap structures including zero-bias conductance peaks induced by the presence of the ferromagnet.

  8. Dynamics of a nanoscale Josephson junction probed by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ast, Christian R.; Jaeck, Berthold; Eltschka, Matthias; Etzkorn, Markus [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Kern, Klaus [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Institut de Physique de la Matiere Condensee, EPFL, Lausanne (Switzerland)

    2015-07-01

    The Josephson effect is an intriguing phenomenon as it presents an interplay of different energy scales, such as the Josephson energy ε{sub J} (critical current), charging energy ε{sub C}, and temperature T. Using a scanning tunneling microscope (STM) operating at a base temperature of 15 mK, we create a nanoscale superconductor-vacuum-superconductor tunnel junction in an extremely underdamped regime (Q>>10). We observe extremely small retrapping currents also owing to strongly reduced ohmic losses in the well-developed superconducting gaps. While formally operating in the zero temperature limit, i.e. the temperature T is smaller than the Josephson plasma frequency ω{sub J} (k{sub B}T<<ℎω{sub J}=√(8ε{sub J}ε{sub C})), experimentally other phenomena, such as stray photons, may perturb the Josephson junction, leading to an effectively higher temperature. The dynamics of the Josephson junction can be addressed experimentally by looking at characteristic parameters, such as the switching current and the retrapping current. We discuss the dynamics of the Josephson junction in the context of reaching the zero temperature limit.

  9. Spin-polarized scanning tunneling microscopy with quantitative insights into magnetic probes.

    Science.gov (United States)

    Phark, Soo-Hyon; Sander, Dirk

    2017-01-01

    Spin-polarized scanning tunneling microscopy and spectroscopy (spin-STM/S) have been successfully applied to magnetic characterizations of individual nanostructures. Spin-STM/S is often performed in magnetic fields of up to some Tesla, which may strongly influence the tip state. In spite of the pivotal role of the tip in spin-STM/S, the contribution of the tip to the differential conductance d I /d V signal in an external field has rarely been investigated in detail. In this review, an advanced analysis of spin-STM/S data measured on magnetic nanoislands, which relies on a quantitative magnetic characterization of tips, is discussed. Taking advantage of the uniaxial out-of-plane magnetic anisotropy of Co bilayer nanoisland on Cu(111), in-field spin-STM on this system has enabled a quantitative determination, and thereby, a categorization of the magnetic states of the tips. The resulting in-depth and conclusive analysis of magnetic characterization of the tip opens new venues for a clear-cut sub-nanometer scale spin ordering and spin-dependent electronic structure of the non-collinear magnetic state in bilayer high Fe nanoislands on Cu(111).

  10. Tunneling Mode of Scanning Electrochemical Microscopy: Probing Electrochemical Processes at Single Nanoparticles.

    Science.gov (United States)

    Sun, Tong; Wang, Dengchao; Mirkin, Michael V

    2018-06-18

    Electrochemical experiments at individual nanoparticles (NPs) can provide new insights into their structure-activity relationships. By using small nanoelectrodes as tips in a scanning electrochemical microscope (SECM), we recently imaged individual surface-bound 10-50 nm metal NPs. Herein, we introduce a new mode of SECM operation based on tunneling between the tip and a nanoparticle immobilized on the insulating surface. The obtained current vs. distance curves show the transition from the conventional feedback response to electron tunneling between the tip and the NP at separation distances of less than about 3 nm. In addition to high-resolution imaging of the NP topography, the tunneling mode enables measurement of the heterogeneous kinetics at a single NP without making an ohmic contact with it. The developed method should be useful for studying the effects of nanoparticle size and geometry on electrocatalytic activity in real-world applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Josephson scanning tunneling microscopy -- a local and direct probe of the superconducting order parameter

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Hikari; Dynes, Robert; Barber Jr., Richard. P.; Ono, S.; Ando, Y.

    2009-09-01

    Direct measurements of the superconducting superfluid on the surface of vacuum-cleaved Bi2Sr2CaCu2O8+delta (BSCCO) samples are reported. These measurements are accomplished via Josephson tunneling into the sample using a novel scanning tunneling microscope (STM) equipped with a superconducting tip. The spatial resolution of the STM of lateral distances less than the superconducting coherence length allows it to reveal local inhomogeneities in the pair wavefunction of the BSCCO. Instrument performance is demonstrated first with Josephson measurements of Pb films followed by the layered superconductor NbSe2. The relevant measurement parameter, the Josephson ICRN product, is discussed within the context of both BCS superconductors and the high transition temperature superconductors. The local relationship between the ICRN product and the quasiparticle density of states (DOS) gap are presented within the context of phase diagrams for BSCCO. Excessive current densities can be produced with these measurements and have been found to alter the local DOS in the BSCCO. Systematic studies of this effect were performed to determine the practical measurement limits for these experiments. Alternative methods for preparation of the BSCCO surface are also discussed.

  12. Observation of HCI-induced nanostructures with a scanning probe microscope

    International Nuclear Information System (INIS)

    Tona, Masahide; Watanabe, Hirofumi; Takahashi, Satoshi; Fujita, Yuso; Abe, Takashi; Jian, Sun; Nakamura, Nobuyuki; Yoshiyasu, Nobuo; Yamada, Chikashi; Sakurai, Makoto; Ohtani, Shunsuke

    2007-01-01

    We present scanning tunneling microscope (STM) images, atomically resolved, of the nanostructures on various kinds of surfaces bombarded with highly charged ions (HCIs). In the STM image of a highly oriented pyrolytic graphite surface (Xe 29+ -impact), a protrusion structure was observed with √3 x √3 R30 0 surface reconstruction around the impact site. A crater-like structure was formed on a Si(111)-(7x7) surface by an I 50+ -HCI impact. An atomic image of ∼0.1 nm in height was also observed around the missing topmost layers of the crater. In the case of a TiO 2 (110) surface, a typical nanostructure induced by a single I 51+ -HCI impact, relatively larger crater structure than that on the Si surface was observed; the height (∼1 nm) was higher than the atomic step of the TiO 2 (110)-(1x1) surface (∼0.3 nm) and the depth reached at least 1.5 nm. This implies that the degree of the HCI-radiation effect on the TiO 2 surface is higher than that of the Si(111) case

  13. Surface characterization of superconductive Nd1Ba2Cu3Oy thin films using scanning probe microscopes

    International Nuclear Information System (INIS)

    Ting, W.; Badaye, M.; Itti, R.; Morishita, T.; Koshizuka, N.; Tanaka, S.

    1996-01-01

    Recently, superconductive Nd 1 Ba 2 Cu 3 O y (Nd123) thin films with high superconducting transition temperature (T c ) have been successfully fabricated at the authors institute employing the standard laser ablation method. In this paper, they report parts of the results of surface characterization of the Nd123 thin films using an ultrahigh vacuum scanning tunneling microscope/spectroscopy (UHV-STM/STS) and an atomic force microscope (AFM) system operated in air. Clear spiral pattern is observed on the surfaces of Nd123 thin films by STM and AFM, suggesting that films are formed by two-dimensional island growth mode at the final growing stage. Contour plots of the spirals show that the step heights of the spirals are not always the integer or half integer numbers of the c-axis parameter of the structure. This implies that the surface natural termination layer of the films may not be unique. Surface atomic images of the as-prepared Nd123 thin films are obtained employing both STM and AFM. STS measurements show that most of the surfaces are semiconductive, or sometimes even metallic. The results of STS measurements together with the fact that they are able to see the surface atomic images using scanning probe microscopes suggest that exposure to air does not cause serious degradation to the as-prepared surfaces of Nd123 thin films

  14. Principal component and spatial correlation analysis of spectroscopic-imaging data in scanning probe microscopy

    International Nuclear Information System (INIS)

    Jesse, Stephen; Kalinin, Sergei V

    2009-01-01

    An approach for the analysis of multi-dimensional, spectroscopic-imaging data based on principal component analysis (PCA) is explored. PCA selects and ranks relevant response components based on variance within the data. It is shown that for examples with small relative variations between spectra, the first few PCA components closely coincide with results obtained using model fitting, and this is achieved at rates approximately four orders of magnitude faster. For cases with strong response variations, PCA allows an effective approach to rapidly process, de-noise, and compress data. The prospects for PCA combined with correlation function analysis of component maps as a universal tool for data analysis and representation in microscopy are discussed.

  15. Tools to probe the universe; Des outils pour sonder l'univers

    Energy Technology Data Exchange (ETDEWEB)

    Lagage, P.O.; Augueres, J.L.; Amiaux, J.; Cara, Ch.; Fontignie, J.; Rio, Y.; Fermon, C.; Pannetier-Lecoeur, M.; De Vismes, A.; Cordier, B.; Fesquet, M.; Ferrando, Ph.; Authier, M.; Pantin, E.; Glicenstein, J.F.; Boulade, O.; Refregier, A.; Stolarczyk, Th.; Agnese, P.; Rodriguez, L.; Agnese, P.; Pigot, C.; Duband, L.; Limousin, O.; Delagnes, E.; Turck-Chieze, S.; Carton, P.H.; Starck, J.L.; Bournaud, F.; Teyssier, R.; Audit, E.; Brun, A.S.; Leca, P.; Menache, Ch.; Pomarede, D.; Thooris, B.; Meis, C.

    2009-07-01

    This special issue of Clefs CEA journal is entirely devoted to astrophysics and to the exploration and probing of the Universe. The second part of this dossier, described here, makes a status of the tools used to probe the universe: telescopes, imaging spectrometers, data processing and simulation. Content: A - Telescopes of the future: 1. Seeing further out: JWST: looking back on a past 13 billion years old, Space specifics: the learning curve to know-how, Fabricating a corona-graph mask, SVOM, a satellite to detect the explosions of the first stars to be formed in the Universe; 2. Seeing more precisely: SIMBOL-X, pioneering formation flying, ELT/METIS, a 42-meter giant, One hundred telescopes for the CTA arrays; 3. Seeing wider: Euclid, mapping the extragalactic sky, ANTARES: the neutrino, another cosmic messenger; B - The new generation of imaging spectrometers: Observing the Universe in the submillimeter spectral region, The X-ray Universe, Space cryo-coolers, Out in the extreme, tumultuous Universe, Probing the Sun with GOLF-NG, Focus: From light to imagery; C - Data analysis in astrophysics; D - Numerical simulation in astrophysics: Information technology and theoretical predictions in astrophysics, Supercomputers for a better understanding of the Universe, The visualization of astrophysical simulations, Godunov, a numerical platform for education and research

  16. Screening length and quantum capacitance in graphene by scanning probe microscopy.

    Science.gov (United States)

    Giannazzo, F; Sonde, S; Raineri, V; Rimini, E

    2009-01-01

    A nanoscale investigation on the capacitive behavior of graphene deposited on a SiO2/n(+) Si substrate (with SiO2 thickness of 300 or 100 nm) was carried out by scanning capacitance spectroscopy (SCS). A bias V(g) composed by an AC signal and a slow DC voltage ramp was applied to the macroscopic n(+) Si backgate of the graphene/SiO(2)/Si capacitor, while a nanoscale contact was obtained on graphene by the atomic force microscope tip. This study revealed that the capacitor effective area (A(eff)) responding to the AC bias is much smaller than the geometrical area of the graphene sheet. This area is related to the length scale on which the externally applied potential decays in graphene, that is, the screening length of the graphene 2DEG. The nonstationary charges (electrons/holes) induced by the AC potential spread within this area around the contact. A(eff) increases linearly with the bias and in a symmetric way for bias inversion. For each bias V(g), the value of A(eff) is related to the minimum area necessary to accommodate the not stationary charges, according to the graphene density of states (DOS) at V(g). Interestingly, by decreasing the SiO(2) thickness from 300 to 100 nm, the slope of the A(eff) versus bias curve strongly increases (by a factor of approximately 50). The local quantum capacitance C(q) in the contacted graphene region was calculated starting from the screening length, and the distribution of the values of C(q) for different tip positions was obtained. Finally the lateral variations of the DOS in graphene was determined.

  17. BFPTool: a software tool for analysis of Biomembrane Force Probe experiments.

    Science.gov (United States)

    Šmít, Daniel; Fouquet, Coralie; Doulazmi, Mohamed; Pincet, Frédéric; Trembleau, Alain; Zapotocky, Martin

    2017-01-01

    The Biomembrane Force Probe is an approachable experimental technique commonly used for single-molecule force spectroscopy and experiments on biological interfaces. The technique operates in the range of forces from 0.1 pN to 1000 pN. Experiments are typically repeated many times, conditions are often not optimal, the captured video can be unstable and lose focus; this makes efficient analysis challenging, while out-of-the-box non-proprietary solutions are not freely available. This dedicated tool was developed to integrate and simplify the image processing and analysis of videomicroscopy recordings from BFP experiments. A novel processing feature, allowing the tracking of the pipette, was incorporated to address a limitation of preceding methods. Emphasis was placed on versatility and comprehensible user interface implemented in a graphical form. An integrated analytical tool was implemented to provide a faster, simpler and more convenient way to process and analyse BFP experiments.

  18. Genetically-encoded tools for cAMP probing and modulation in living systems.

    Directory of Open Access Journals (Sweden)

    Valeriy M Paramonov

    2015-09-01

    Full Text Available Intracellular 3'-5'-cyclic adenosine monophosphate (cAMP is one of the principal second messengers downstream of a manifold of signal transduction pathways, including the ones triggered by G protein-coupled receptors. Not surprisingly, biochemical assays for cAMP have been instrumental for basic research and drug discovery for decades, providing insights into cellular physiology and guiding pharmaceutical industry. However, despite impressive track record, the majority of conventional biochemical tools for cAMP probing share the same fundamental shortcoming - all the measurements require sample disruption for cAMP liberation. This common bottleneck, together with inherently low spatial resolution of measurements (as cAMP is typically analyzed in lysates of thousands of cells, underpin the ensuing limitations of the conventional cAMP assays: 1 genuine kinetic measurements of cAMP levels over time in a single given sample are unfeasible; 2 inability to obtain precise information on cAMP spatial distribution and transfer at subcellular levels, let alone the attempts to pinpoint dynamic interactions of cAMP and its effectors. At the same time, tremendous progress in synthetic biology over the recent years culminated in drastic refinement of our toolbox, allowing us not only to bypass the limitations of conventional assays, but to put intracellular cAMP life-span under tight control – something, that seemed scarcely attainable before. In this review article we discuss the main classes of modern genetically-encoded tools tailored for cAMP probing and modulation in living systems. We examine the capabilities and weaknesses of these different tools in the context of their operational characteristics and applicability to various experimental set-ups involving living cells, providing the guidance for rational selection of the best tools for particular needs.

  19. Abdominal computed tomography scan as a screening tool in blunt trauma

    International Nuclear Information System (INIS)

    Brasel, K.J.; Borgstrom, D.C.; Kolewe, K.A.

    1997-01-01

    Background. One of the most difficult problems in blunt trauma is evaluation for potential intraabdominal injury. Admission for serial abdominal exams remains the standard of care after intraabdominal injury has been initially excluded. We hypothesized a normal abdominal computed tomography (CT) scan in a subgroup of minimally injured patients would obviate admission for serial abdominal examinations, allowing safe discharge from the emergency department (ED). Methods. We reviewed our blunt trauma experience with patients admitted solely for serial abdominal examinations after a normal CT. Patients were identified from the trauma registry at a Level 1 trauma center from July 1991 through June 1995. Patients with abnormal CTs, extra-abdominal injuries necessitating admission, hemodynamic abnormalities, a Glasgow Coma Scale less than 13, or injury severity scores (ISSs) greater than 15 were excluded. Records of 238 patients remained; we reviewed them to determine the presence of missed abdominal injury. Results. None of the 238 patients had a missed abdominal injury. Average ISS of these patients was 3.2 (range, 0 to 10). Discharging these patients from the ED would result in a yearly cost savings of $32,874 to our medical system. Conclusions. Abdominal CT scan is a safe and cost-effective screening tool in patients with blunt trauma. A normal CT scan in minimally injured patients allows safe discharge from the ED. (authors)

  20. CDPP supporting tools to Solar Orbiter and Parker Solar Probe data exploitation

    Science.gov (United States)

    Genot, V. N.; Cecconi, B.; Dufourg, N.; Gangloff, M.; André, N.; Bouchemit, M.; Jacquey, C.; Pitout, F.; Rouillard, A.; Nathanaël, J.; Lavraud, B.; Durand, J.; Tao, C.; Buchlin, E.; Witasse, O. G.

    2017-12-01

    In recent years the French Centre de Données de la Physique des Plasmas (CDPP) has extended its data analysis capability by designing a number of new tools. In the solar and heliospheric contexts, and in direct support to the forthcoming solar ESA and NASA missions in these fields, these tools comprise of the Propagation Tool which helps linking solar perturbations observed both in remote and in-situ data; this is achieved through direct connection to the companion solar database MEDOC and the CDPP AMDA database. More recently, in the frame of Europlanet 2020 RI, a 1D MHD solar wind propagation code (Tao et al., 2005) has been interfaced to provide real time solar wind monitors at cruising probes and planetary environments using ACE real time data as inputs (Heliopropa service). Finally, simulations, models and data may be combined and visualized in a 3D context with 3DView. This presentation will overview the various functionalities of these tools and provide examples, in particular a 'CME tracking' case recently published (Witasse et al., 2017). Europlanet 2020 RI has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.

  1. Measurement Variability of Vertical Scanning Interferometry Tool Used for Orbiter Window Defect Assessment

    Science.gov (United States)

    Padula, Santo, II

    2009-01-01

    The ability to sufficiently measure orbiter window defects to allow for window recertification has been an ongoing challenge for the orbiter vehicle program. The recent Columbia accident has forced even tighter constraints on the criteria that must be met in order to recertify windows for flight. As a result, new techniques are being investigated to improve the reliability, accuracy and resolution of the defect detection process. The methodology devised in this work, which is based on the utilization of a vertical scanning interferometric (VSI) tool, shows great promise for meeting the ever increasing requirements for defect detection. This methodology has the potential of a 10-100 fold greater resolution of the true defect depth than can be obtained from the currently employed micrometer based methodology. An added benefit is that it also produces a digital elevation map of the defect, thereby providing information about the defect morphology which can be utilized to ascertain the type of debris that induced the damage. However, in order to successfully implement such a tool, a greater understanding of the resolution capability and measurement repeatability must be obtained. This work focused on assessing the variability of the VSI-based measurement methodology and revealed that the VSI measurement tool was more repeatable and more precise than the current micrometer based approach, even in situations where operator variation could affect the measurement. The analysis also showed that the VSI technique was relatively insensitive to the hardware and software settings employed, making the technique extremely robust and desirable

  2. Topographic and electronic contrast of the graphene moir´e on Ir(111) probed by scanning tunneling microscopy and noncontact atomic force microscopy

    NARCIS (Netherlands)

    Sun, Z.; Hämäläinen, K.; Sainio, K.; Lahtinen, J.; Vanmaekelbergh, D.A.M.; Liljeroth, P.

    2011-01-01

    Epitaxial graphene grown on transition-metal surfaces typically exhibits a moir´e pattern due to the lattice mismatch between graphene and the underlying metal surface. We use both scanning tunneling microscopy (STM) and atomic force microscopy (AFM) to probe the electronic and topographic contrast

  3. In situ study of Li-ions diffusion and deformation in Li-rich cathode materials by using scanning probe microscopy techniques

    Science.gov (United States)

    Zeng, Kaiyang; Li, Tao; Tian, Tian

    2017-08-01

    In this paper, the scanning probe microscopy (SPM) based techniques, namely, conductive-AFM, electrochemical strain microscopy (ESM) and AM-FM (amplitude modulation-frequency modulation) techniques, are used to in situ characterize the changes in topography, conductivity and elastic properties of Li-rich layered oxide cathode (Li1.2Mn0.54Ni0.13Co0.13O2) materials, in the form of nanoparticles, when subject to the external electric field. Nanoparticles are the basic building blocks for composite cathode in a Li-ion rechargeable battery. Characterization of the structure and electrochemical properties of the nanoparticles is very important to understand the performance and reliability of the battery materials and devices. In this study, the conductivity, deformation and mechanical properties of the Li-rich oxide nanoparticles under different polarities of biases are studied using the above-mentioned SPM techniques. This information can be correlated with the Li+-ion diffusion and migration in the particles under external electrical field. The results also confirm that the SPM techniques are ideal tools to study the changes in various properties of electrode materials at nano- to micro-scales during or after the ‘simulated’ battery operation conditions. These techniques can also be used to in situ characterize the electrochemical performances of other energy storage materials, especially in the form of the nanoparticles.

  4. Surface and bulk 3D analysis of natural and processed ruby using electron probe micro analyzer and X-ray micro CT scan

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, Rakesh K., E-mail: rakesh.materialscience@gmail.com; Singh, Saroj K.; Mishra, B.K.

    2016-08-15

    Highlights: • Firm linking between two advance techniques: Micro-CT and EPMA for mineral analysis. • Attempt to identify and differentiate the treated gem stone from natural counterpart. • 3D structural and surface elemental analysis of the natural gem stone. - Abstract: The change in surface compositional and bulk structural characteristics of the natural ruby stone, before and after heat treatment with lead oxide has been analyzed using two advance characterization techniques like: X-ray micro CT scan (μ-CT) and electron probe micro analyzer (EPMA). The analytical correlation between these two techniques in identification as well as in depth study of the ores and minerals before and after processing has been presented. Also, we describe the aesthetic enhancement of a low quality defective ruby stone by lead oxide filling and the sequential analysis of this ruby stone before and after treatment using these two advanced techniques to identify and to confirm the change in its aesthetic value. The cracks healing and pores filling by the metal oxide on the surface of the ruby have been analyzed using μ-CT and EPMA. Moreover, in this work we describe the advance characterization of the repaired gem stones especially ruby stones. This work will light up the path for in-depth understanding of diffusion mechanism and abstract information of impurity particles inside the minerals. Based on these observations, EPMA and micro CT are shown to be powerful tools for the identification as well as research in gem stones.

  5. Computer Tool for Automatically Generated 3D Illustration in Real Time from Archaeological Scanned Pieces

    Directory of Open Access Journals (Sweden)

    Luis López

    2012-11-01

    Full Text Available The graphical documentation process of archaeological pieces requires the active involvement of a professional artist to recreate beautiful illustrations using a wide variety of expressive techniques. Frequently, the artist’s work is limited by the inconvenience of working only with the photographs of the pieces he is going to illustrate. This paper presents a software tool that allows the easy generation of illustrations in real time from 3D scanned models. The developed interface allows the user to simulate very elaborate artistic styles through the creation of diagrams by using the available virtual lights. The software processes the diagrams to render an illustration from any given angle or position. Among the available virtual lights, there are well known techniques as silhouettes enhancement, hatching or toon shading.

  6. Scanning electron microscopy and electron probe microanalyses of the crystalline components of human and animal dental calculi

    International Nuclear Information System (INIS)

    LeGeros, R.Z.; Orly, I.; LeGeros, J.P.; Gomez, C.; Kazimiroff, J.; Tarpley, T.; Kerebel, B.

    1988-01-01

    A review of the use of scanning electron microscopy (SEM) and electron probe microanalyses in the study of dental calculus showed that such studies provided confirmatory and supplementary data on the morphological features of human dental calculi but gave only limited information on the identity of the crystalline or inorganic components. This study aimed to explore the potential of combined SEM and microanalyses in the identification of the crystalline components of the human and animal dental calculi. Human and animal calculi were analyzed. Identification of the crystalline components were made based on the combined information of the morphology (SEM) and Ca/P molar ratios of the crystals with the morphology and Ca/P molar ratio of synthetic calcium phosphates (brushite or DCPD; octacalcium phosphate, OCP; Mg-substituted whitlockite, beta-TCMP; CO 3 -substituted apatite, (CHA); and calcite. SEM showed similarities in morphological features of human and animal dental calculi but differences in the forms of crystals present. Microanalyses and crystal morphology data suggested the presence of CaCO 3 (calcite) and CHA in the animal (cat, dog, tiger) and of OCP, beta-TCMP and CHA in human dental calculi. X-ray diffraction and infrared (IR) absorption analyses confirmed these results. This exploratory study demonstrated that by taking into consideration what is known about the crystalline components of human and animal dental calculi, combined SEM and microanalyses can provide qualitative identification

  7. Contact resistance asymmetry of amorphous indium-gallium-zinc-oxide thin-film transistors by scanning Kelvin probe microscopy

    Science.gov (United States)

    Chen-Fei, Wu; Yun-Feng, Chen; Hai, Lu; Xiao-Ming, Huang; Fang-Fang, Ren; Dun-Jun, Chen; Rong, Zhang; You-Dou, Zheng

    2016-05-01

    In this work, a method based on scanning Kelvin probe microscopy is proposed to separately extract source/drain (S/D) series resistance in operating amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors. The asymmetry behavior of S/D contact resistance is deduced and the underlying physics is discussed. The present results suggest that the asymmetry of S/D contact resistance is caused by the difference in bias conditions of the Schottky-like junction at the contact interface induced by the parasitic reaction between contact metal and a-IGZO. The overall contact resistance should be determined by both the bulk channel resistance of the contact region and the interface properties of the metal-semiconductor junction. Project supported by the Key Industrial R&D Program of Jiangsu Province, China (Grant No. BE2015155), the Priority Academic Program Development of Higher Education Institutions of Jiangsu Province, China, and the Fundamental Research Funds for the Central Universities, China (Grant No. 021014380033).

  8. Scanning Hall-probe microscopy system for two-dimensional imaging of critical current density in RE-123 coated conductors

    International Nuclear Information System (INIS)

    Higashikawa, K.; Inoue, M.; Kawaguchi, T.; Shiohara, K.; Imamura, K.; Kiss, T.; Iijima, Y.; Kakimoto, K.; Saitoh, T.; Izumi, T.

    2011-01-01

    Nondestructive characterization method of in-plane distribution of critical current density for coated conductors. Current distribution in a coated conductor compared with that from theoretical analysis. Relationship between local critical current density and local magnetic field. We have developed a characterization method for two-dimensional imaging of critical current density in coated conductors (CCs) based on scanning Hall-probe microscopy (SHPM). The distributions of the magnetic field around a sample were measured for several different conditions of external magnetic fields, and then were converted to those of the sheet current density which flowed to shield the external magnetic field or to trap the penetrated magnetic field. As a result, it was found that the amplitude of the sheet current density corresponded to that of critical current density almost in all the area of the sample except for the region where current direction changed. This indicates that we could obtain an in-plane distribution of the critical current density with a spatial resolution of around 100 μm in non-destructive manner by this method. We believe that this measurement will be a multifunctional and comprehensive characterization method for coated conductors.

  9. Polymerase chain reaction as a tool for developing stress protein probes

    Energy Technology Data Exchange (ETDEWEB)

    Cochrane, B.J.; Mattley, Y.D. (Univ. of South Florida, Tampa, FL (United States). Dept. of Biology); Snell, T.W. (Georgia Inst. of Tech., Atlanta, GA (United States). Div. of Biology)

    1994-08-01

    Because of the high degree of evolutionary conservation of stress proteins, potential exists for the development of nucleic acid probes from particular species that could be used to monitor stress-related changes in mRNA abundance. The polymerase chain reaction (PCR) is a powerful tool that can be applied to the generation of these probes, provided that primer sequences can be identified that specifically amplify sequences of interest from a wide variety of organisms. The authors identified such sequences from multiple alignments of published chaperonin and stress-70 sequences, and tested their ability to amplify appropriately sized fragments from genomic DNA from a variety of vertebrates and invertebrates. Although no primer pair could be used successfully with all species, the authors were able to derive specific products from most species by testing different pairs. One primer pair for chaperonin proved particularly useful. Products were obtained from all tested species, and with a single exception (human), these primers appeared to amplify a single copy sequence. The authors determined the nucleotide sequence of the product obtained from the rotifer Brachionus plicatilis and determined by phylogenetic analysis of the inferred protein product that the product obtained is most likely derived from a rotifer DNA template. Finally, the authors show that this product can be used to detect changes in abundance of homologous mRNA in heat-stressed rotifers.

  10. In situ spectroscopic ellipsometry as a surface sensitive tool to probe thin film growth

    International Nuclear Information System (INIS)

    Liu, C.

    1999-01-01

    Sputtered thin film and multilayer x-ray mirrors are made routinely at the Advanced Photon Source (APS) for the APS users. Precise film growth control and characterization are very critical in fabricating high-quality x-ray mirrors. Film thickness calibrations are carried out using in situ and ex situ spectroscopic ellipsometry, interferometry, and x-ray scattering. To better understand the growth and optical properties of different thin film systems, we have carried out a systematic study of sputtered thin films of Au, Rh, Pg Pd, Cu, and Cr, using in situ ellipsometry. Multiple data sets were obtained in situ for each film material with incremental thicknesses and were analyzed with their correlation in mind. We found that in situ spectroscopic ellipsometry as a surface-sensitive tool can also be used to probe the growth and morphology of the thin film system. This application of in situ spectroscopic ellipsometry for metal thin film systems will be discussed

  11. Correlations between reaction product yields as a tool for probing heavy-ion reaction scenarios

    International Nuclear Information System (INIS)

    Gawlikowicz, W.; Agnihotri, D. K.; Baldwin, S. A.; Schroeder, W. U.; Toke, J.; Charity, R. J.; Sarantites, D. G.; Sobotka, L. G.; Souza, R. T. de; Barczyk, T.; Grotowski, K.; Micek, S.; Planeta, R.; Sosin, Z.

    2010-01-01

    Experimental multidimensional joint distributions of neutrons and charged reaction products were analyzed for 136 Xe + 209 Bi reactions at E/A=28, 40, and 62 MeV and were found to exhibit several different types of prominent correlation patterns. Some of these correlations have a simple explanation in terms of the system excitation energy and pose little challenge to most statistical decay theories. However, several other types of correlation patterns are difficult to reconcile with some, but not other, possible reaction scenarios. In this respect, correlations between the average atomic numbers of intermediate-mass fragments, on the one hand, and light particle multiplicities, on the other, are notable. This kind of multiparticle correlation provides a useful tool for probing reaction scenarios, which is different from the traditional approach of interpreting inclusive yields of individual reaction products.

  12. Delineating Beach and Dune Morphology from Massive Terrestrial Laser Scanning Data Using the Generic Mapping Tools

    Science.gov (United States)

    Zhou, X.; Wang, G.; Yan, B.; Kearns, T.

    2016-12-01

    Terrestrial laser scanning (TLS) techniques have been proven to be efficient tools to collect three-dimensional high-density and high-accuracy point clouds for coastal research and resource management. However, the processing and presenting of massive TLS data is always a challenge for research when targeting a large area with high-resolution. This article introduces a workflow using shell-scripting techniques to chain together tools from the Generic Mapping Tools (GMT), Geographic Resources Analysis Support System (GRASS), and other command-based open-source utilities for automating TLS data processing. TLS point clouds acquired in the beach and dune area near Freeport, Texas in May 2015 were used for the case study. Shell scripts for rotating the coordinate system, removing anomalous points, assessing data quality, generating high-accuracy bare-earth DEMs, and quantifying beach and sand dune features (shoreline, cross-dune section, dune ridge, toe, and volume) are presented in this article. According to this investigation, the accuracy of the laser measurements (distance from the scanner to the targets) is within a couple of centimeters. However, the positional accuracy of TLS points with respect to a global coordinate system is about 5 cm, which is dominated by the accuracy of GPS solutions for obtaining the positions of the scanner and reflector. The accuracy of TLS-derived bare-earth DEM is primarily determined by the size of grid cells and roughness of the terrain surface for the case study. A DEM with grid cells of 4m x 1m (shoreline by cross-shore) provides a suitable spatial resolution and accuracy for deriving major beach and dune features.

  13. γ-Glutamyl-dipeptides: Easy tools to rapidly probe the stereoelectronic properties of ionotropic glutamate receptor binding pocket

    DEFF Research Database (Denmark)

    Tamborini, Lucia; Nicosia, Veronica; Conti, Paola

    2016-01-01

    γ-Glutamyl-dipeptides, built by condensing the distal carboxylate of L-Glu (or D-Glu) onto a series of differently functionalized amino acids, were prepared and used as tools for rapidly probing the stereoelectronic properties of iGluRs, searching for subtype-selective ligands.......γ-Glutamyl-dipeptides, built by condensing the distal carboxylate of L-Glu (or D-Glu) onto a series of differently functionalized amino acids, were prepared and used as tools for rapidly probing the stereoelectronic properties of iGluRs, searching for subtype-selective ligands....

  14. Designing topological defects in 2D materials using scanning probe microscopy and a self-healing mechanism: a density functional-based molecular dynamics study

    Science.gov (United States)

    Popov, Igor; Đurišić, Ivana; Belić, Milivoj R.

    2017-12-01

    Engineering of materials at the atomic level is one of the most important aims of nanotechnology. The unprecedented ability of scanning probe microscopy to address individual atoms opened up the possibilities for nanomanipulation and nanolitography of surfaces and later on of two-dimensional materials. While the state-of-the-art scanning probe lithographic methods include, primarily, adsorption, desorption and repositioning of adatoms and molecules on substrates or tailoring nanoribbons by etching of trenches, the precise modification of the intrinsic atomic structure of materials is yet to be advanced. Here we introduce a new concept, scanning probe microscopy with a rotating tip, for engineering of the atomic structure of membranes based on two-dimensional materials. In order to indicate the viability of the concept, we present our theoretical research, which includes atomistic modeling, molecular dynamics simulations, Fourier analysis and electronic transport calculations. While stretching can be employed for fabrication of atomic chains only, our comprehensive molecular dynamics simulations indicate that nanomanipulation by scanning probe microscopy with a rotating tip is capable of assembling a wide range of topological defects in two-dimensional materials in a rather controllable and reproducible manner. We analyze two possibilities. In the first case the probe tip is retracted from the membrane while in the second case the tip is released beneath the membrane allowing graphene to freely relax and self-heal the pore made by the tip. The former approach with the tip rotation can be achieved experimentally by rotation of the sample, which is equivalent to rotation of the tip, whereas irradiation of the membrane by nanoclusters can be utilized for the latter approach. The latter one has the potential to yield a yet richer diversity of topological defects on account of a lesser determinacy. If successfully realized experimentally the concept proposed here could

  15. Optical method for distance and displacement measurements of the probe-sample separation in a scanning near-field optical microscope

    International Nuclear Information System (INIS)

    Santamaria, L.; Siller, H. R.; Garcia-Ortiz, C. E.; Cortes, R.; Coello, V.

    2016-01-01

    In this work, we present an alternative optical method to determine the probe-sample separation distance in a scanning near-field optical microscope. The experimental method is based in a Lloyd’s mirror interferometer and offers a measurement precision deviation of ∼100 nm using digital image processing and numerical analysis. The technique can also be strategically combined with the characterization of piezoelectric actuators and stability evaluation of the optical system. It also opens the possibility for the development of an automatic approximation control system valid for probe-sample distances from 5 to 500 μm.

  16. Optical method for distance and displacement measurements of the probe-sample separation in a scanning near-field optical microscope

    Energy Technology Data Exchange (ETDEWEB)

    Santamaria, L.; Siller, H. R. [Tecnológico de Monterrey, Eugenio Garza Sada 2501 Sur, Monterrey, N.L., 64849 (Mexico); Garcia-Ortiz, C. E., E-mail: cegarcia@cicese.mx [CONACYT Research Fellow – CICESE, Unidad Monterrey, Alianza Centro 504, Apodaca, NL, 66629 (Mexico); Cortes, R.; Coello, V. [CICESE, Unidad Monterrey, PIIT, Alianza Centro 504, Apodaca, NL, 66629 (Mexico)

    2016-04-15

    In this work, we present an alternative optical method to determine the probe-sample separation distance in a scanning near-field optical microscope. The experimental method is based in a Lloyd’s mirror interferometer and offers a measurement precision deviation of ∼100 nm using digital image processing and numerical analysis. The technique can also be strategically combined with the characterization of piezoelectric actuators and stability evaluation of the optical system. It also opens the possibility for the development of an automatic approximation control system valid for probe-sample distances from 5 to 500 μm.

  17. The use of Scanning Tunneling Microscope as a novel characterization tool for metallic alloys

    International Nuclear Information System (INIS)

    Brezenitsky, M.; Moreh, R.; Dayan, D.; Kimmel, G.

    1996-01-01

    A novel method is reported for characterizing the microstructure of metals and alloys by utilizing the surface imaging properties of a STM (Scanning Tunneling microscope). In the present work there is no need to take advantage of the high atomic resolution of the STM, instead only gross resolution is required. Twenty different samples having different grain sizes (caused by the mosaic structure) and ranging between 20 to 200 nm were prepared. These dimensions are far below the resolution limit of optical microscopes. The samples were first studied using line profile analysis of XRD spectra while focusing on two of the most characteristic properties of steel which are: grain size and the deviation from cubic symmetry. Some of the samples showed nonuniform XRD line broadening effects, which could be attributed to a tetragonal distortion. If it is true, the samples must consist of martensitic twinned structure, as a result of the typical y to a shear transformation in steels. The samples were then studied using the STM. In general, many 1000 nm x 1000 )zm STM scans were carried out on each sample. In all cases of irregular XRD line broadening, the STM identified bands and sub-bands in the images which fitted the usual twining structure in steels. In addition, the STM images were found to show individual domains, from which histograms of the grain dimensions for each sample were prepared and compared to the XRD data. An excellent agreement was observed between tile two sets of data of grain sizes. The present method is much simpler than that which employs the Transmission Electron Microscope (TEM) as it can be carried out in air and no special requirements on sample preparation is necessary. This work establishes the STM as a very useful characterization tool for studies in metallurgy and metal physics. (author)

  18. IL17eScan: A Tool for the Identification of Peptides Inducing IL-17 Response

    Directory of Open Access Journals (Sweden)

    Sudheer Gupta

    2017-10-01

    Full Text Available IL-17 cytokines are pro-inflammatory cytokines and are crucial in host defense against various microbes. Induction of these cytokines by microbial antigens has been investigated in the case of ischemic brain injury, gingivitis, candidiasis, autoimmune myocarditis, etc. In this study, we have investigated the ability of amino acid sequence of antigens to induce IL-17 response using machine-learning approaches. A total of 338 IL-17-inducing and 984 IL-17 non-inducing peptides were retrieved from Immune Epitope Database. 80% of the data were randomly selected as training dataset and rest 20% as validation dataset. To predict the IL-17-inducing ability of peptides/protein antigens, different sequence-based machine-learning models were developed. The performance of support vector machine (SVM and random forest (RF was compared with different parameters to predict IL-17-inducing epitopes (IIEs. The dipeptide composition-based SVM-model displayed an accuracy of 82.4% with Matthews correlation coefficient = 0.62 at polynomial (t = 1 kernel on 10-fold cross-validation and outperformed RF. Amino acid residues Leu, Ser, Arg, Asn, and Phe and dipeptides LL, SL, LK, IL, LI, NL, LR, FK, SF, and LE are abundant in IIEs. The present tool helps in the identification of IIEs using machine-learning approaches. The induction of IL-17 plays an important role in several inflammatory diseases, and identification of such epitopes would be of great help to the immunologists. It is freely available at http://metagenomics.iiserb.ac.in/IL17eScan/ and http://metabiosys.iiserb.ac.in/IL17eScan/.

  19. Controlled attenuation parameter using the FibroScan® XL probe for quantification of hepatic steatosis for non-alcoholic fatty liver disease in an Asian population.

    Science.gov (United States)

    Chan, Wah-Kheong; Nik Mustapha, Nik Raihan; Wong, Grace Lai-Hung; Wong, Vincent Wai-Sun; Mahadeva, Sanjiv

    2017-02-01

    The FibroScan® XL probe reduces failure of liver stiffness measurement (LSM) and unreliable results in obese patients. The objective of this article is to evaluate the accuracy of controlled attenuation parameter (CAP) obtained using the XL probe for the estimation of hepatic steatosis in patients with non-alcoholic fatty liver disease (NAFLD). Adult NAFLD patients with a liver biopsy within six months were included and were examined with the FibroScan® M and XL probes. Histopathological findings were reported according to the Non-Alcoholic Steatohepatitis Clinical Research Network Scoring System. Participants who did not have fatty liver on ultrasonography were recruited as controls. A total of 57 NAFLD patients and 22 controls were included. The mean age of the NAFLD patients and controls was 50.1 ± 10.4 years and 20.2 ± 1.3 years, respectively ( p  = 0.000). The mean body mass index was 30.2 ± 5.0 kg per m 2 and 20.5 ± 2.4 kg per m 2 , respectively ( p  = 0.000). The distribution of steatosis grades were: S0, 29%; S1, 17%; S2, 35%; S3, 19%. The AUROC for estimation of steatosis grade ≥ S1, S2 and S3 was 0.94, 0.80 and 0.69, respectively, using the M probe, and 0.97, 0.81 and 0.67, respectively, using the XL probe. CAP obtained using the XL probe had similar accuracy as the M probe for the estimation of hepatic steatosis in NAFLD patients.

  20. AMS. A powerful tool for probing nucleosynthesis via long-lived radionuclides

    International Nuclear Information System (INIS)

    Wallner, A.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.; Kaeppeler, F.

    2005-01-01

    The potential of accelerator mass spectrometry (AMS) will be demonstrated on typical radionuclides of interest with half-lives between some years and up to hundred million years. The Vienna Environmental Research Accelerator (VERA) represents a state-of-the-art AMS facility which provides the ability for quantifying nuclides over the whole mass range. At VERA, AMS is used for quantifying long-lived radionuclides within a wide range of applications - from archaeology to astrophysics. Lack of information on cross section data exists for a list of nuclides pointed out by nuclear data requests. The potential of AMS as a powerful tool for probing nucleosynthesis will be demonstrated by means of some prime examples. Recent developments in the technique of AMS will be highlighted and some applications of AMS in astrophysics will be discussed. In addition, an overview on detection limits, measurement precision as well as the recent measurement program at VERA for quantifying such long-lived radionuclides will be presented. (author)

  1. MetAlign: Interface-Driven, Versatile Metabolomics Tool for Hyphenated Full-Scan Mass Spectrometry Data Preprocessing

    NARCIS (Netherlands)

    Lommen, A.

    2009-01-01

    Hyphenated full-scan MS technology creates large amounts of data. A versatile easy to handle automation tool aiding in the data analysis is very important in handling such a data stream. MetAlign software-as described in this manuscript-handles a broad range of accurate mass and nominal mass GC/MS

  2. Computer Vision Tool and Technician as First Reader of Lung Cancer Screening CT Scans

    NARCIS (Netherlands)

    Ritchie, A.J.; Sanghera, C.; Jacobs, C.; Zhang, W.; Mayo, J.; Schmidt, H.; Gingras, M.; Pasian, S.; Stewart, L.; Tsai, S.; Manos, D.; Seely, J.M.; Burrowes, P.; Bhatia, R.; Atkar-Khattra, S.; Ginneken, B. van; Tammemagi, M.; Tsao, M.S.; Lam, S.; et al.,

    2016-01-01

    To implement a cost-effective low-dose computed tomography (LDCT) lung cancer screening program at the population level, accurate and efficient interpretation of a large volume of LDCT scans is needed. The objective of this study was to evaluate a workflow strategy to identify abnormal LDCT scans in

  3. Analysis of non-contact and contact probe-to-sample thermal exchange for quantitative measurements of thin film and nanostructure thermal conductivity by the scanning hot probe method

    Science.gov (United States)

    Wilson, Adam A.

    The ability to measure thermal properties of thin films and nanostructured materials is an important aspect of many fields of academic study. A strategy especially well-suited for nanoscale investigations of these properties is the scanning hot probe technique, which is unique in its ability to non-destructively interrogate the thermal properties with high resolution, both laterally as well as through the thickness of the material. Strategies to quantitatively determine sample thermal conductivity depend on probe calibration. State of the art calibration strategies assume that the area of thermal exchange between probe and sample does not vary with sample thermal conductivity. However, little investigation has gone into determining whether or not that assumption is valid. This dissertation provides a rigorous study into the probe-to-sample heat transfer through the air gap at diffusive distances for a variety of values of sample thermal conductivity. It is demonstrated that the thermal exchange radius and gap/contact thermal resistance varies with sample thermal conductivity as well as tip-to-sample clearance in non-contact mode. In contact mode, it is demonstrated that higher thermal conductivity samples lead to a reduction in thermal exchange radius for Wollaston probe tips. Conversely, in non-contact mode and in contact mode for sharper probe tips where air contributes the most to probe-to-sample heat transfer, the opposite trend occurs. This may be attributed to the relatively strong solid-to-solid conduction occurring between probe and sample for the Wollaston probes. A three-dimensional finite element (3DFE) model was developed to investigate how the calibrated thermal exchange parameters vary with sample thermal conductivity when calibrating the probe via the intersection method in non-contact mode at diffusive distances. The 3DFE model was then used to explore the limits of sensitivity of the experiment for a range of simulated experimental conditions. It

  4. Gamma ray scanning as troubleshooting tool for unusual and large diameter refinery vacuum columns

    International Nuclear Information System (INIS)

    Sarkar, T.K.; Chawla, R.; Banik, S.; Chopra, S.J.; Singh, G.; Pant, H.J.; Sreeramakrishnan, P.; Dhar, D.C.; Pushpangathan, P.N.; Sharma, V.K.

    1997-01-01

    Gamma scanning of trayed and packed columns is widely used to obtain density profiles and identify on-line problems such as: damaged tray or packing, foaming, flooding, maldistribution, weeping and entrainment, etc. However, scanning of large diameter tray or packed columns requires expertise in handling high intensity gamma sources along with thorough understanding of distillation engineering. Engineers India Limited and the Bhabha Atomic Research Centre undertook scanning of two such large diameter (8.4 m and 7.4 m) trayed and packed refinery vacuum distillation columns and successfully diagnosed the problems and suggested remedial actions. Radiography testing of small diameter columns can be used to confirm gamma scanning results. One such example for ammonia separator column is given

  5. A versatile LabVIEW and field-programmable gate array-based scanning probe microscope for in operando electronic device characterization.

    Science.gov (United States)

    Berger, Andrew J; Page, Michael R; Jacob, Jan; Young, Justin R; Lewis, Jim; Wenzel, Lothar; Bhallamudi, Vidya P; Johnston-Halperin, Ezekiel; Pelekhov, Denis V; Hammel, P Chris

    2014-12-01

    Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In operando characterization of such devices by scanning probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanning probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field-programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically biased graphene field-effect transistor device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.

  6. Computer Vision Tool and Technician as First Reader of Lung Cancer Screening CT Scans.

    Science.gov (United States)

    Ritchie, Alexander J; Sanghera, Calvin; Jacobs, Colin; Zhang, Wei; Mayo, John; Schmidt, Heidi; Gingras, Michel; Pasian, Sergio; Stewart, Lori; Tsai, Scott; Manos, Daria; Seely, Jean M; Burrowes, Paul; Bhatia, Rick; Atkar-Khattra, Sukhinder; van Ginneken, Bram; Tammemagi, Martin; Tsao, Ming Sound; Lam, Stephen

    2016-05-01

    To implement a cost-effective low-dose computed tomography (LDCT) lung cancer screening program at the population level, accurate and efficient interpretation of a large volume of LDCT scans is needed. The objective of this study was to evaluate a workflow strategy to identify abnormal LDCT scans in which a technician assisted by computer vision (CV) software acts as a first reader with the aim to improve speed, consistency, and quality of scan interpretation. Without knowledge of the diagnosis, a technician reviewed 828 randomly batched scans (136 with lung cancers, 556 with benign nodules, and 136 without nodules) from the baseline Pan-Canadian Early Detection of Lung Cancer Study that had been annotated by the CV software CIRRUS Lung Screening (Diagnostic Image Analysis Group, Nijmegen, The Netherlands). The scans were classified as either normal (no nodules ≥1 mm or benign nodules) or abnormal (nodules or other abnormality). The results were compared with the diagnostic interpretation by Pan-Canadian Early Detection of Lung Cancer Study radiologists. The overall sensitivity and specificity of the technician in identifying an abnormal scan were 97.8% (95% confidence interval: 96.4-98.8) and 98.0% (95% confidence interval: 89.5-99.7), respectively. Of the 112 prevalent nodules that were found to be malignant in follow-up, 92.9% were correctly identified by the technician plus CV compared with 84.8% by the study radiologists. The average time taken by the technician to review a scan after CV processing was 208 ± 120 seconds. Prescreening CV software and a technician as first reader is a promising strategy for improving the consistency and quality of screening interpretation of LDCT scans. Copyright © 2016 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

  7. Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

    Directory of Open Access Journals (Sweden)

    Walla Frederik

    2018-01-01

    Full Text Available We investigated the excitation of surface plasmon polaritons on gold films with the metallized probe tip of a scattering-type scanning near-field optical microscope (s-SNOM. The emission of the polaritons from the tip, illuminated by near-infrared laser radiation, was found to be anisotropic and not circularly symmetric as expected on the basis of literature data. We furthermore identified an additional excitation channel via light that was reflected off the tip and excited the plasmon polaritons at the edge of the metal film. Our results, while obtained for a non-rotationally-symmetric type of probe tip and thus specific for this situation, indicate that when an s-SNOM is employed for the investigation of plasmonic structures, the unintentional excitation of surface waves and anisotropic surface wave propagation must be considered in order to correctly interpret the signatures of plasmon polariton generation and propagation.

  8. Growth and decay dynamics of a stable microbubble produced at the end of a near-field scanning optical microscopy fiber probe

    International Nuclear Information System (INIS)

    Taylor, R.S.; Hnatovsky, C.

    2004-01-01

    Low power cw laser radiation coupled into a near-field scanning optical microscopy fiber probe has been used to generate a stable microbubble in water. A probe tip which was selectively chemically etched and metallized served as a microheater for the generation of the stable bubble. Bubble diameters in the range of 40-400 μm and lifetimes of over an hour have been obtained. The microbubble exhibited a linear growth phase over a period of a few seconds before reaching a maximum diameter which depended on the laser power. When the laser beam was blocked the microbubble decayed with a rate which was inversely proportional to the bubble diameter. The bubble lifetime depended on the square of the initial bubble diameter. Instabilities which transform a large stable bubble into a microjet stream of micron sized bubbles as the laser power was increased is also described

  9. Detecting variants with Metabolic Design, a new software tool to design probes for explorative functional DNA microarray development

    Directory of Open Access Journals (Sweden)

    Gravelat Fabrice

    2010-09-01

    Full Text Available Abstract Background Microorganisms display vast diversity, and each one has its own set of genes, cell components and metabolic reactions. To assess their huge unexploited metabolic potential in different ecosystems, we need high throughput tools, such as functional microarrays, that allow the simultaneous analysis of thousands of genes. However, most classical functional microarrays use specific probes that monitor only known sequences, and so fail to cover the full microbial gene diversity present in complex environments. We have thus developed an algorithm, implemented in the user-friendly program Metabolic Design, to design efficient explorative probes. Results First we have validated our approach by studying eight enzymes involved in the degradation of polycyclic aromatic hydrocarbons from the model strain Sphingomonas paucimobilis sp. EPA505 using a designed microarray of 8,048 probes. As expected, microarray assays identified the targeted set of genes induced during biodegradation kinetics experiments with various pollutants. We have then confirmed the identity of these new genes by sequencing, and corroborated the quantitative discrimination of our microarray by quantitative real-time PCR. Finally, we have assessed metabolic capacities of microbial communities in soil contaminated with aromatic hydrocarbons. Results show that our probe design (sensitivity and explorative quality can be used to study a complex environment efficiently. Conclusions We successfully use our microarray to detect gene expression encoding enzymes involved in polycyclic aromatic hydrocarbon degradation for the model strain. In addition, DNA microarray experiments performed on soil polluted by organic pollutants without prior sequence assumptions demonstrate high specificity and sensitivity for gene detection. Metabolic Design is thus a powerful, efficient tool that can be used to design explorative probes and monitor metabolic pathways in complex environments

  10. Scanning Hall-probe microscopy of a vortex and field fluctuations in La1.85Sr0.15CuO4 films

    International Nuclear Information System (INIS)

    Chang, A.M.; Hallen, H.D.; Hess, H.F.; Kwo, J.; Sudboe, A.; Kao, H.L.; Chang, T.Y.

    1992-01-01

    A high-resolution scanning Hall-probe microscope is used to spatially resolve vortices in high-temperature superconducting La 1.85 Sr 0.15 CuO 4 films. At low magnetic fields, a disordered vortex arrangement is observed. A fit to the surface field of an individual vortex is consistent with one flux quantum, and is used to determine the local penetration depth and its temperature dependence. At higher fields, magnetic fluctuations are observed and compared to a collective pinning model. For films grown with the c-axis tilted from the surface normal, oval vortices are observed. (orig.)

  11. Rapid Prototyping — A Tool for Presenting 3-Dimensional Digital Models Produced by Terrestrial Laser Scanning

    Directory of Open Access Journals (Sweden)

    Juho-Pekka Virtanen

    2014-07-01

    Full Text Available Rapid prototyping has received considerable interest with the introduction of affordable rapid prototyping machines. These machines can be used to manufacture physical models from three-dimensional digital mesh models. In this paper, we compare the results obtained with a new, affordable, rapid prototyping machine, and a traditional professional machine. Two separate data sets are used for this, both of which were acquired using terrestrial laser scanning. Both of the machines were able to produce complex and highly detailed geometries in plastic material from models based on terrestrial laser scanning. The dimensional accuracies and detail levels of the machines were comparable, and the physical artifacts caused by the fused deposition modeling (FDM technique used in the rapid prototyping machines could be found in both models. The accuracy of terrestrial laser scanning exceeded the requirements for manufacturing physical models of large statues and building segments at a 1:40 scale.

  12. Preoperative Duplex Scanning is a Helpful Diagnostic Tool in Neurogenic Thoracic Outlet Syndrome.

    Science.gov (United States)

    Orlando, Megan S; Likes, Kendall C; Mirza, Serene; Cao, Yue; Cohen, Anne; Lum, Ying Wei; Freischlag, Julie A

    2016-01-01

    To evaluate the diagnostic role of venous and arterial duplex scanning in neurogenic thoracic outlet syndrome (NTOS). Retrospective review of patients who underwent duplex ultrasonography prior to first rib resection and scalenectomy (FRRS) for NTOS from 2005 to 2013. Abnormal scans included ipsilateral compression (IC) with abduction of the symptomatic extremity (>50% change in subclavian vessel flow), contralateral (asymptomatic side) compression (CC) or bilateral compression (BC). A total of 143 patients (76% female, average age 34, range 13-59) underwent bilateral preoperative duplex scanning. Ipsilateral compression was seen in 44 (31%), CC in 12 (8%), and BC in 14 (10%). Seventy-three (51%) patients demonstrated no compression. Patients with IC more often experienced intraoperative pneumothoraces (49% vs. 25%, P duplex ultrasonography can assist in NTOS diagnosis. Ipsilateral compression on abduction often correlates with Adson testing. © The Author(s) 2016.

  13. Simulators of tray distillation columns as tools for interpreting gamma-ray scan profile signal

    International Nuclear Information System (INIS)

    Offei-Mensah, P.S.; Gbadago, J.K.; Dagadu, C.P.K.; Danso, K.A.

    2008-01-01

    Simulators of tray distillation columns were used to provide technical guidelines for interpreting signals from gamma ray scans used for analysing malfunctions in distillation columns. The transmitted radiation intensities at 0.05 m intervals were determined from top to bottom of simulators of tray distillation columns exposed to 20 mCi of '1'3'7 Cs. Signals generated from the simulators were identical with the experimental signals obtained from the stabilizer column of the crude oil distillation unit at the Tema Oil Refinery Ghana Limited. Changes in the signal level were observed with changes in diameter, type of material (gasoline, air, debris, steel) and orientation of scan line. The analysis provided accurate interpretation of gamma scan profiles. (au)

  14. PRIMEGENSw3: a web-based tool for high-throughput primer and probe design.

    Science.gov (United States)

    Kushwaha, Garima; Srivastava, Gyan Prakash; Xu, Dong

    2015-01-01

    Highly specific and efficient primer and probe design has been a major hurdle in many high-throughput techniques. Successful implementation of any PCR or probe hybridization technique depends on the quality of primers and probes used in terms of their specificity and cross-hybridization. Here we describe PRIMEGENSw3, a set of web-based utilities for high-throughput primer and probe design. These utilities allow users to select genomic regions and to design primer/probe for selected regions in an interactive, user-friendly, and automatic fashion. The system runs the PRIMEGENS algorithm in the back-end on the high-performance server with the stored genomic database or user-provided custom database for cross-hybridization check. Cross-hybridization is checked not only using BLAST but also by checking mismatch positions and energy calculation of potential hybridization hits. The results can be visualized online and also can be downloaded. The average success rate of primer design using PRIMEGENSw3 is ~90 %. The web server also supports primer design for methylated sequences, which is used in epigenetic studies. Stand-alone version of the software is also available for download at the website.

  15. Development and applications of advanced probing tools for cell wall biology

    DEFF Research Database (Denmark)

    Hansen, Aleksander Riise

    . In this study, antigens consisting of crude mixtures of alkali extracted polymers from the grass model Brachypodium distachyon were targets for probe generation using a naïve human single domain antibody library. Epitope characterization of positive clones from phage ELISA was then further elucidated...... the function of pectin methyl esterase inhibitors and their role in plant defense against microbial degradation, and cell wall structural dynamics in relation to cell detachment from roots. The second part describes phage display as a method for developing probes against targets that are poor immunogens...

  16. Multimodal fiber-probe spectroscopy as a clinical tool for diagnosing and classifying biological tissues

    Science.gov (United States)

    Cicchi, Riccardo; Anand, Suresh; Fantechi, Riccardo; Giordano, Flavio; Gacci, Mauro; Conti, Valerio; Nesi, Gabriella; Buccoliero, Anna Maria; Carini, Marco; Guerrini, Renzo; Pavone, Francesco Saverio

    2017-07-01

    An optical fiber probe for multimodal spectroscopy was designed, developed and used for tissue diagnostics. The probe, based on a fiber bundle with optical fibers of various size and properties, allows performing spectroscopic measurements with different techniques, including fluorescence, Raman, and diffuse reflectance, using the same probe. Two visible laser diodes were used for fluorescence spectroscopy, a laser diode emitting in the NIR was used for Raman spectroscopy, and a fiber-coupled halogen lamp for diffuse reflectance. The developed probe was successfully employed for diagnostic purposes on various tissues, including brain and bladder. In particular, the device allowed discriminating healthy tissue from both tumor and dysplastic tissue as well as to perform tumor grading. The diagnostic capabilities of the method, determined using a cross-validation method with a leave-one-out approach, demonstrated high sensitivity and specificity for all the examined samples, as well as a good agreement with histopathological examination performed on the same samples. The obtained results demonstrated that the multimodal approach is crucial for improving diagnostic capabilities with respect to what can be obtained from individual techniques. The experimental setup presented here can improve diagnostic capabilities on a broad range of tissues and has the potential of being used clinically for guiding surgical resection in the near future.

  17. Reproducible analysis of sequencing-based RNA structure probing data with user-friendly tools

    DEFF Research Database (Denmark)

    Kielpinski, Lukasz Jan; Sidiropoulos, Nikos; Vinther, Jeppe

    2015-01-01

    time also made analysis of the data challenging for scientists without formal training in computational biology. Here, we discuss different strategies for data analysis of massive parallel sequencing-based structure-probing data. To facilitate reproducible and standardized analysis of this type of data...

  18. Shear force distance control in a scanning near-field optical microscope: in resonance excitation of the fiber probe versus out of resonance excitation

    International Nuclear Information System (INIS)

    Lapshin, D.A.; Letokhov, V.S.; Shubeita, G.T.; Sekatskii, S.K.; Dietler, G.

    2004-01-01

    The experimental results of the direct measurement of the absolute value of interaction force between the fiber probe of a scanning near-field optical microscope (SNOM) operated in shear force mode and a sample, which were performed using combined SNOM-atomic force microscope setup, are discussed for the out-of-resonance fiber probe excitation mode. We demonstrate that the value of the tapping component of the total force for this mode at typical dither amplitudes is of the order of 10 nN and thus is quite comparable with the value of this force for in resonance fiber probe excitation mode. It is also shown that for all modes this force component is essentially smaller than the usually neglected static attraction force, which is of the order of 200 nN. The true contact nature of the tip-sample interaction during the out of resonance mode is proven. From this, we conclude that such a detection mode is very promising for operation in liquids, where other modes encounter great difficulties

  19. Collagen imaged by Coherent X-ray Diffraction: towards a complementary tool to conventional scanning SAXS

    International Nuclear Information System (INIS)

    Berenguer de la Cuesta, Felisa; Bean, Richard J; Bozec, Laurent; Robinson, Ian K; McCallion, Catriona; Wallace, Kris; Hiller, Jen C; Terrill, Nicholas J

    2010-01-01

    Third generation x-ray sources offer unique possibilities for exploiting coherence in the study of materials. New insights in the structure and dynamics of soft condensed matter and biological samples can be obtained by coherent x-ray diffraction (CXD). However, the experimental procedures for applying these methods to collagen tissues are still under development. We present here an investigation for the optimal procedure in order to obtain high quality CXD data from collagen tissues. Sample handling and preparation and adequate coherence defining apertures are among the more relevant factors to take into account. The impact of the results is also discussed, in particular in comparison with the information that can be extracted from conventional scanning small angle x-ray scattering (SAXS). Images of collagen tissues obtained by CXD reconstructions will give additional information about the local structure with higher resolution and will complement scanning SAXS images.

  20. Collagen imaged by Coherent X-ray Diffraction: towards a complementary tool to conventional scanning SAXS

    Energy Technology Data Exchange (ETDEWEB)

    Berenguer de la Cuesta, Felisa; Bean, Richard J; Bozec, Laurent; Robinson, Ian K [London Centre for Nanotechnology (LCN), University College London (UCL), London WC1H 0AH (United Kingdom); McCallion, Catriona; Wallace, Kris [Department of Physics and Astronomy, University College London (UCL), London WC1E 6BT (United Kingdom); Hiller, Jen C; Terrill, Nicholas J, E-mail: f.berenguer@ucl.ac.u [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2010-10-01

    Third generation x-ray sources offer unique possibilities for exploiting coherence in the study of materials. New insights in the structure and dynamics of soft condensed matter and biological samples can be obtained by coherent x-ray diffraction (CXD). However, the experimental procedures for applying these methods to collagen tissues are still under development. We present here an investigation for the optimal procedure in order to obtain high quality CXD data from collagen tissues. Sample handling and preparation and adequate coherence defining apertures are among the more relevant factors to take into account. The impact of the results is also discussed, in particular in comparison with the information that can be extracted from conventional scanning small angle x-ray scattering (SAXS). Images of collagen tissues obtained by CXD reconstructions will give additional information about the local structure with higher resolution and will complement scanning SAXS images.

  1. Environmental Scanning Electron Microscope As A Tool For Imaging Of Native State Somatic Embryogenesis

    Czech Academy of Sciences Publication Activity Database

    Neděla, Vilém; Hřib, J.; Svidenská, S.; Vooková, B.; Runštuk, Jiří

    2012-01-01

    Roč. 18, Suppl. 2 (2012), s. 1270-1271 ISSN 1431-9276 R&D Projects: GA ČR GAP102/10/1410; GA MPO FR-TI1/305; GA MPO FR-TI1/118; GA MŠk EE.2.3.20.0103 Institutional support: RVO:68081731 Keywords : environmental scanning electron microscopy * somatic embryogenesis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.495, year: 2012

  2. Influence of Surface Adsorption on Work Function Measurements on Gold-Platinum Interface Using Scanning Kelvin Probe Microscopy

    International Nuclear Information System (INIS)

    Mugo, Simon; Yuan Jun

    2012-01-01

    Surface potential difference (SPD) on freshly coated gold and platinum electrodes have been found to be much smaller than bulk work functions consideration and to be dependent on time. We show these discrepancies arise due to formation of surface dipoles caused by adsorbed contaminants in ambient environments. The process is reversible by gentle annealing consistent with contaminant hypothesis. Examination of potential changes on individual electrodes suggest that the Pt surface is more sensitive to ambient conditions than the Au surface in accordance with their relative chemical activities. The result has great implication for interpretation of Kelvin probe measurements obtained on practical devices exposed to ambient environments.

  3. Design and testing of microfabricated surgical tools for large animal probe insertion

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, Shelly [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-05

    Neural probes provide therapeutic stimulation for neuropsychiatric disorders or record neural activity to investigate the workings of the brain. Researchers utilize 6 mm long temporary silicon stiffeners attached with biodissolvable adhesive to insert flexible neural probes into rat brains, but increasing the probe length fivefold makes inserting large animal probes a significant challenge because of an increased potential for buckling. This study compared the insertion success rates of 6 mm and 30 mm long silicon stiffeners that were 80 μm wide and 30 μm thick, and ascertained the material thickness and modulus of elasticity that would provide successful insertion for a 30 mm probe. Using a microdrive, stiffeners were inserted into an agarose brain phantom at controlled insertion speeds while being video-recorded. Twenty-five percent of the 30 mm silicon stiffeners fully inserted at speeds approximately four times higher than the target rate of 0.13 mm/s, while 100 percent of the 6 mm silicon stiffeners inserted successfully at target speed. Critical buckling loads (Pcr) were calculated for the 6 mm and 30 mm silicon stiffeners, and for 30 mm diamond and tungsten stiffeners, with thicknesses varying from 30-80 μm. Increasing the thickness of the material by 10 μm, 20 μm and 30 μm improved the Pcr by 2.4, 4.7 and 8.2 times, respectively, independent of the material, and substituting diamond for silicon multiplied the buckling capacity by 5.0 times. Stiffeners made of silicon for large animal probe insertion are not strong enough to withstand buckling upon insertion without a significant increase in thickness. Replacing silicon with diamond and increasing the thickness of the stiffener to 50 μm would afford a stiffener with the same Pcr capacity as the 6 mm silicon stiffener that had a 100 percent insertion success rate. Experiments should continue with diamond to determine a minimum thickness that will ensure successful

  4. Band Alignment in MoS2/WS2 Transition Metal Dichalcogenide Heterostructures Probed by Scanning Tunneling Microscopy and Spectroscopy.

    Science.gov (United States)

    Hill, Heather M; Rigosi, Albert F; Rim, Kwang Taeg; Flynn, George W; Heinz, Tony F

    2016-08-10

    Using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS), we examine the electronic structure of transition metal dichalcogenide heterostructures (TMDCHs) composed of monolayers of MoS2 and WS2. STS data are obtained for heterostructures of varying stacking configuration as well as the individual monolayers. Analysis of the tunneling spectra includes the influence of finite sample temperature, yield information about the quasi-particle bandgaps, and the band alignment of MoS2 and WS2. We report the band gaps of MoS2 (2.16 ± 0.04 eV) and WS2 (2.38 ± 0.06 eV) in the materials as measured on the heterostructure regions and the general type II band alignment for the heterostructure, which shows an interfacial band gap of 1.45 ± 0.06 eV.

  5. Electrochemical reverse engineering: A systems-level tool to probe the redox-based molecular communication of biology.

    Science.gov (United States)

    Li, Jinyang; Liu, Yi; Kim, Eunkyoung; March, John C; Bentley, William E; Payne, Gregory F

    2017-04-01

    The intestine is the site of digestion and forms a critical interface between the host and the outside world. This interface is composed of host epithelium and a complex microbiota which is "connected" through an extensive web of chemical and biological interactions that determine the balance between health and disease for the host. This biology and the associated chemical dialogues occur within a context of a steep oxygen gradient that provides the driving force for a variety of reduction and oxidation (redox) reactions. While some redox couples (e.g., catecholics) can spontaneously exchange electrons, many others are kinetically "insulated" (e.g., biothiols) allowing the biology to set and control their redox states far from equilibrium. It is well known that within cells, such non-equilibrated redox couples are poised to transfer electrons to perform reactions essential to immune defense (e.g., transfer from NADH to O 2 for reactive oxygen species, ROS, generation) and protection from such oxidative stresses (e.g., glutathione-based reduction of ROS). More recently, it has been recognized that some of these redox-active species (e.g., H 2 O 2 ) cross membranes and diffuse into the extracellular environment including lumen to transmit redox information that is received by atomically-specific receptors (e.g., cysteine-based sulfur switches) that regulate biological functions. Thus, redox has emerged as an important modality in the chemical signaling that occurs in the intestine and there have been emerging efforts to develop the experimental tools needed to probe this modality. We suggest that electrochemistry provides a unique tool to experimentally probe redox interactions at a systems level. Importantly, electrochemistry offers the potential to enlist the extensive theories established in signal processing in an effort to "reverse engineer" the molecular communication occurring in this complex biological system. Here, we review our efforts to develop this

  6. Development of thermal scanning probe microscopy for the determination of thin films thermal conductivity: application to ceramic materials for nuclear industry

    International Nuclear Information System (INIS)

    David, L.

    2006-10-01

    Since the 1980's, various thermal metrologies have been developed to understand and characterize the phenomena of transport of thermal energy at microscopic and submicroscopic scales. Thermal Scanning Probe Microscopy (SThM) is promising. Based on the analysis of the thermal interaction between an heated probe and a sample, it permits to probe the matter at the level of micrometric size in volumes. Performed in the framework of the development of this technique, this work more particularly relates to the study of thin films thermal conductivity. We propose a new modelling of the prediction of measurement with SThM. This model allows not only the calibration of the method for the measurement of bulk material thermal conductivity but also to specify and to better describe the probe - sample thermal coupling and to estimate, from its inversion, thin films thermal conductivity. This new approach of measurement has allowed the determination of the thermal conductivity of micrometric and sub-micrometric thicknesses of meso-porous silicon thin film in particular. Our estimates for the micrometric thicknesses are in agreement with those obtained by the use of Raman spectrometry. For the lower thicknesses of film, we give new data. Our model has, moreover, allowed a better definition of the in-depth resolution of the apparatus. This one is strongly linked to the sensitivity of SThM and strongly depends on the probe-sample thermal coupling area and on the geometry of the probe used. We also developed the technique by the vacuum setting of SThM. Our first results under this environment of measurement are encouraging and validate the description of the coupling used in our model. Our method was applied to the study of ceramics (SiC, TiN, TiC and ZrC) under consideration in the composition of future nuclear fuels. Because of the limitations of SThM in terms of sensitivity to thermal conductivity and in-depth resolution, measurements were also undertaken with a modulated thermo

  7. An open tool for input function estimation and quantification of dynamic PET FDG brain scans.

    Science.gov (United States)

    Bertrán, Martín; Martínez, Natalia; Carbajal, Guillermo; Fernández, Alicia; Gómez, Álvaro

    2016-08-01

    Positron emission tomography (PET) analysis of clinical studies is mostly restricted to qualitative evaluation. Quantitative analysis of PET studies is highly desirable to be able to compute an objective measurement of the process of interest in order to evaluate treatment response and/or compare patient data. But implementation of quantitative analysis generally requires the determination of the input function: the arterial blood or plasma activity which indicates how much tracer is available for uptake in the brain. The purpose of our work was to share with the community an open software tool that can assist in the estimation of this input function, and the derivation of a quantitative map from the dynamic PET study. Arterial blood sampling during the PET study is the gold standard method to get the input function, but is uncomfortable and risky for the patient so it is rarely used in routine studies. To overcome the lack of a direct input function, different alternatives have been devised and are available in the literature. These alternatives derive the input function from the PET image itself (image-derived input function) or from data gathered from previous similar studies (population-based input function). In this article, we present ongoing work that includes the development of a software tool that integrates several methods with novel strategies for the segmentation of blood pools and parameter estimation. The tool is available as an extension to the 3D Slicer software. Tests on phantoms were conducted in order to validate the implemented methods. We evaluated the segmentation algorithms over a range of acquisition conditions and vasculature size. Input function estimation algorithms were evaluated against ground truth of the phantoms, as well as on their impact over the final quantification map. End-to-end use of the tool yields quantification maps with [Formula: see text] relative error in the estimated influx versus ground truth on phantoms. The main

  8. BFPTool: a software tool for analysis of Biomembrane Force Probe experiments

    Czech Academy of Sciences Publication Activity Database

    Šmít, Daniel; Fouquet, C.; Doulazmi, M.; Pincet, F.; Trembleau, A.; Zápotocký, Martin

    2017-01-01

    Roč. 10, Feb (2017), č. článku 2. ISSN 2046-1682 R&D Projects: GA ČR(CZ) GA14-16755S; GA MŠk(CZ) 7AMB12FR002 Institutional support: RVO:67985823 Keywords : Biomembrane Force Probe * motion tracking * image analysis * force spectroscopy * cell mechanics Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 2.292, year: 2016

  9. Scanning capacitance microscope as a tool for the characterization of integrated circuits

    Science.gov (United States)

    Born, A.; Wiesendanger, R.

    With the decreasing size of integrated circuits (ICs), there is an increasing demand for the measurement of doping profiles with high spatial resolution. The scanning capacitance microscope (SCM) offers the possibility of measuring 2D dopant profiles with spatial resolution of less than 20 nm. A great problem of the SCM technique is the influence of previous measurements on subsequent ones. We have observed hysteresis in the SCM images and measured low-frequency C-V curves with high-frequency equipment. A theoretical model was developed to understand this phenomenon. We are now undertaking the first steps using the SCM as a standard device for the characterization of ICs.

  10. Label-Free Imaging of Female Genital Tract Melanocytic Lesions With Pump-Probe Microscopy: A Promising Diagnostic Tool.

    Science.gov (United States)

    Robles, Francisco E; Deb, Sanghamitra; Fischer, Martin C; Warren, Warren S; Selim, Maria Angelica

    2017-04-01

    Melanomas of the female genital tract present a unique clinical challenge. Not only are these lesions in an anatomically sensitive area, but also they tend to be multifocal and have high recurrence rates. Furthermore, several benign melanocytic proliferations resemble early-stage melanoma clinically and/or histopathologically. Thus, there is a significant need for additional tools that can help correctly diagnose and stage these lesions. Here, we quantitatively and nondestructively analyze the chemical composition of melanin in excised pigmented lesions of the female genital tract using pump-probe microscopy, a high-resolution optical imaging technique that is sensitive to many biochemical properties of melanin. Thirty-one thin (~5 μm) tissue sections previously excised from female genital tract melanocytic lesions were imaged with pump-probe microscopy and analyzed. We find significant quantitative differences in melanin type and structure between melanoma and nonmalignant melanocytic proliferations. Our analysis also suggests a link between the molecular signatures of melanins and lesion-specific genetic mutations. Finally, significant differences are found between metastatic and nonmetastatic melanomas. The limitations of this work include the fact that molecular information is restricted to melanin pigment and the sample size is relatively small. Pump-probe microscopy provides unique information regarding the biochemical composition of genital tract melanocytic lesions, which can be used to improve the diagnosis and staging of vulvar melanomas.

  11. A novel optical tool for controlling and probing ultrafast surface dynamics

    International Nuclear Information System (INIS)

    Yang, Yudong

    2017-12-01

    Ultrashort pulse laser sources have been greatly developed over the past few decades. The available pulse duration has been reduced to the single-cycle pulse regime. The discovery of high harmonic generation has freed us from the limitation of the laser wavelength. Moreover, the demonstration of isolated attosecond pulse generation has indicated the advent of the attosecond science era. Attosecond pulses undoubtedly allow one to study ultrafast dynamics with unprecedented time resolution. However, physical systems with genuine attosecond time scale dynamics are rather challenging to find. Ultrafast surface charge transfer, which is an important process in photochemistry and electrochemistry, is a good candidate experimental system exhibiting attosecond electronic dynamics. Specifically, the ultrafast surface charge transfer on the c(4 x 2)S/Ru(0001) surface was previously studied and the charge transfer time inferred to be 320 as using core-hole clock spectroscopy at a synchrotron facility. In order to measure this benchmark attosecond electronic dynamics with real time-resolving methods, pump pulses centered at 160 eV and probe pulses centered at 40 eV are required. To this end, a dedicated attosecond experimental beamline including an ultrashort laser pulse source and an attosecond pulse generation and characterization setup has been designed and is being developed. The author of this thesis was responsible for the construction of the attosecond experimental beamline which will be used ultrafast surface charge transfer studies. In this thesis, a completely functional attosecond extreme ultraviolet (XUV) beamline, which includes a few-cycle laser pulse source, an attosecond pulse generation and characterization setup, is described. A commercial Ti:sapphire-based chirped-pulse amplification (CPA) laser system is the overall source of the beamline. The laser system is actively carrier-envelope phase (CEP) stabilized and the output pulse duration is ∝35 fs. The

  12. A novel optical tool for controlling and probing ultrafast surface dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yudong

    2017-12-15

    Ultrashort pulse laser sources have been greatly developed over the past few decades. The available pulse duration has been reduced to the single-cycle pulse regime. The discovery of high harmonic generation has freed us from the limitation of the laser wavelength. Moreover, the demonstration of isolated attosecond pulse generation has indicated the advent of the attosecond science era. Attosecond pulses undoubtedly allow one to study ultrafast dynamics with unprecedented time resolution. However, physical systems with genuine attosecond time scale dynamics are rather challenging to find. Ultrafast surface charge transfer, which is an important process in photochemistry and electrochemistry, is a good candidate experimental system exhibiting attosecond electronic dynamics. Specifically, the ultrafast surface charge transfer on the c(4 x 2)S/Ru(0001) surface was previously studied and the charge transfer time inferred to be 320 as using core-hole clock spectroscopy at a synchrotron facility. In order to measure this benchmark attosecond electronic dynamics with real time-resolving methods, pump pulses centered at 160 eV and probe pulses centered at 40 eV are required. To this end, a dedicated attosecond experimental beamline including an ultrashort laser pulse source and an attosecond pulse generation and characterization setup has been designed and is being developed. The author of this thesis was responsible for the construction of the attosecond experimental beamline which will be used ultrafast surface charge transfer studies. In this thesis, a completely functional attosecond extreme ultraviolet (XUV) beamline, which includes a few-cycle laser pulse source, an attosecond pulse generation and characterization setup, is described. A commercial Ti:sapphire-based chirped-pulse amplification (CPA) laser system is the overall source of the beamline. The laser system is actively carrier-envelope phase (CEP) stabilized and the output pulse duration is ∝35 fs. The

  13. Community Health Environment Scan Survey (CHESS): a novel tool that captures the impact of the built environment on lifestyle factors.

    Science.gov (United States)

    Wong, Fiona; Stevens, Denise; O'Connor-Duffany, Kathleen; Siegel, Karen; Gao, Yue

    2011-03-07

    Novel efforts and accompanying tools are needed to tackle the global burden of chronic disease. This paper presents an approach to describe the environments in which people live, work, and play. Community Health Environment Scan Survey (CHESS) is an empirical assessment tool that measures the availability and accessibility, of healthy lifestyle options lifestyle options. CHESS reveals existing community assets as well as opportunities for change, shaping community intervention planning efforts by focusing on community-relevant opportunities to address the three key risk factors for chronic disease (i.e. unhealthy diet, physical inactivity, and tobacco use). The CHESS tool was developed following a review of existing auditing tools and in consultation with experts. It is based on the social-ecological model and is adaptable to diverse settings in developed and developing countries throughout the world. For illustrative purposes, baseline results from the Community Interventions for Health (CIH) Mexico site are used, where the CHESS tool assessed 583 food stores and 168 restaurants. Comparisons between individual-level survey data from schools and community-level CHESS data are made to demonstrate the utility of the tool in strategically guiding intervention activities. The environments where people live, work, and play are key factors in determining their diet, levels of physical activity, and tobacco use. CHESS is the first tool of its kind that systematically and simultaneously examines how built environments encourage/discourage healthy eating, physical activity, and tobacco use. CHESS can help to design community interventions to prevent chronic disease and guide healthy urban planning. © 2011 Fiona Wong et al.

  14. Community Health Environment Scan Survey (CHESS: a novel tool that captures the impact of the built environment on lifestyle factors

    Directory of Open Access Journals (Sweden)

    Fiona Wong

    2011-03-01

    Full Text Available Background: Novel1 1This study was performed on behalf of the Community Interventions for Health (CIH collaboration. efforts and accompanying tools are needed to tackle the global burden of chronic disease. This paper presents an approach to describe the environments in which people live, work, and play. Community Health Environment Scan Survey (CHESS is an empirical assessment tool that measures the availability and accessibility, of healthy lifestyle options lifestyle options. CHESS reveals existing community assets as well as opportunities for change, shaping community intervention planning efforts by focusing on community-relevant opportunities to address the three key risk factors for chronic disease (i.e. unhealthy diet, physical inactivity, and tobacco use. Methods: The CHESS tool was developed following a review of existing auditing tools and in consultation with experts. It is based on the social-ecological model and is adaptable to diverse settings in developed and developing countries throughout the world. Results: For illustrative purposes, baseline results from the Community Interventions for Health (CIH Mexico site are used, where the CHESS tool assessed 583 food stores and 168 restaurants. Comparisons between individual-level survey data from schools and community-level CHESS data are made to demonstrate the utility of the tool in strategically guiding intervention activities. Conclusion: The environments where people live, work, and play are key factors in determining their diet, levels of physical activity, and tobacco use. CHESS is the first tool of its kind that systematically and simultaneously examines how built environments encourage/discourage healthy eating, physical activity, and tobacco use. CHESS can help to design community interventions to prevent chronic disease and guide healthy urban planning.

  15. Sample mounting and transfer for coupling an ultrahigh vacuum variable temperature beetle scanning tunneling microscope with conventional surface probes

    International Nuclear Information System (INIS)

    Nafisi, Kourosh; Ranau, Werner; Hemminger, John C.

    2001-01-01

    We present a new ultrahigh vacuum (UHV) chamber for surface analysis and microscopy at controlled, variable temperatures. The new instrument allows surface analysis with Auger electron spectroscopy, low energy electron diffraction, quadrupole mass spectrometer, argon ion sputtering gun, and a variable temperature scanning tunneling microscope (VT-STM). In this system, we introduce a novel procedure for transferring a sample off a conventional UHV manipulator and onto a scanning tunneling microscope in the conventional ''beetle'' geometry, without disconnecting the heating or thermocouple wires. The microscope, a modified version of the Besocke beetle microscope, is mounted on a 2.75 in. outer diameter UHV flange and is directly attached to the base of the chamber. The sample is attached to a tripod sample holder that is held by the main manipulator. Under UHV conditions the tripod sample holder can be removed from the main manipulator and placed onto the STM. The VT-STM has the capability of acquiring images between the temperature range of 180--500 K. The performance of the chamber is demonstrated here by producing an ordered array of island vacancy defects on a Pt(111) surface and obtaining STM images of these defects

  16. Fluorescent probes for understanding soil water repellency: the novel application of a chemist's tool to soil science

    Science.gov (United States)

    Balshaw, Helen M.; Davies, Matthew L.; Doerr, Stefan H.; Douglas, Peter

    2015-04-01

    Food security and production is one of the key global issues faced by society. It has become essential to work the land efficiently, through better soil management and agronomy whilst protecting the environment from air and water pollution. The failure of soil to absorb water - soil water repellency can lead to major environmental problems such as increased overland flow and soil erosion, poor uptake of agricultural chemicals, and increased risk of groundwater pollution due to the rapid transfer of contaminants and nutrient leaching through uneven wetting and preferential flow pathways. Understanding the causes of soil hydrophobicity is essential for the development of effective methods for its amelioration, supporting environmental stability and food security. Organic compounds deposited on soil mineral or aggregate surfaces have long been recognised as a major factor in causing soil water repellency. It is widely accepted that the main groups of compounds responsible are long-chain acids, alkanes and other organic compounds with hydrophobic properties. However, when reapplied to sands and soils, the degree of water repellency induced by these compounds and mixtures varied widely with compound type, amount, and mixture, in a seemingly unpredictable way. Fluorescent and phosphorescent probes are widely used in chemistry and biochemistry due to their sensitive response to their physical and chemical environment, such as polarity, and viscosity. However, they have to-date not been used to study soil water repellency. Here we present preliminary work on the evaluation of fluorescent probes as tools to study two poorly understood features that determine the degree of wettability for water repellent soils: (i) the distribution of organics on soils; (ii) the changes in polarity at soil surfaces required for water drops to infiltrate. In our initial work we have examined probes adsorbed onto model soils, prepared by adsorption of specific organics onto acid washed sand

  17. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    Science.gov (United States)

    Saive, Rebecca; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert; Kowalsky, Wolfgang

    2013-12-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces.

  18. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    International Nuclear Information System (INIS)

    Saive, Rebecca; Kowalsky, Wolfgang; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert

    2013-01-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces

  19. Development of a Micro-SPM (Scanning Probe Microscope by Post-Assembly of a MEMS-Stage and an Independent Cantilever

    Directory of Open Access Journals (Sweden)

    Zhi Li

    2007-08-01

    Full Text Available The development of miniature scanning probe microscopes (SPM on the basis of the MEMS technique has gained more and more interest. Here a novel approach is presented to realize a micro-SPM, in which by means of post-assembly a conventional cantilever is mounted onto a MEMS positioning stage and used to detect the topography variation of the surface under test. Compared with other integrated micro-SPMs, the proposed micro-SPM can maintain the lateral resolution by simply renewing its cantilever in use, and therefore features low cost, practicability and longer lifetime. Preliminary experimental results are reported, which demonstrate that the proposed microSPM can be realized.

  20. Scanning micro-Hall probe mapping of magnetic flux distributions and current densities in YBa{sub 2}Cu{sub 3}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Xing, W.; Heinrich, B. [Simon Fraser Univ., British Columbia (Canada); Zhou, H. [CTF Systems, Inc., British Columbia (Canada)] [and others

    1994-12-31

    Mapping of the magnetic flux density B{sub z} (perpendicular to the film plane) for a YBa{sub 2}Cu{sub 3}O{sub 7} thin-film sample was carried out using a scanning micro-Hall probe. The sheet magnetization and sheet current densities were calculated from the B{sub z} distributions. From the known sheet magnetization, the tangential (B{sub x,y}) and normal components of the flux density B were calculated in the vicinity of the film. It was found that the sheet current density was mostly determined by 2B{sub x,y}/d, where d is the film thickness. The evolution of flux penetration as a function of applied field will be shown.

  1. Probing Dirac fermion dynamics in topological insulator Bi2Se3 films with a scanning tunneling microscope.

    Science.gov (United States)

    Song, Can-Li; Wang, Lili; He, Ke; Ji, Shuai-Hua; Chen, Xi; Ma, Xu-Cun; Xue, Qi-Kun

    2015-05-01

    Scanning tunneling microscopy and spectroscopy have been used to investigate the femtosecond dynamics of Dirac fermions in the topological insulator Bi2Se3 ultrathin films. At the two-dimensional limit, bulk electrons become quantized and the quantization can be controlled by the film thickness at a single quintuple layer level. By studying the spatial decay of standing waves (quasiparticle interference patterns) off steps, we measure directly the energy and film thickness dependence of the phase relaxation length lϕ and inelastic scattering lifetime τ of topological surface-state electrons. We find that τ exhibits a remarkable (E - EF)(-2) energy dependence and increases with film thickness. We show that the features revealed are typical for electron-electron scattering between surface and bulk states.

  2. Proposed alteration of images of molecular orbitals obtained using a scanning tunneling microscope as a probe of electron correlation.

    Science.gov (United States)

    Toroz, Dimitrios; Rontani, Massimo; Corni, Stefano

    2013-01-04

    Scanning tunneling spectroscopy (STS) allows us to image single molecules decoupled from the supporting substrate. The obtained images are routinely interpreted as the square moduli of molecular orbitals, dressed by the mean-field electron-electron interaction. Here we demonstrate that the effect of electron correlation beyond the mean field qualitatively alters the uncorrelated STS images. Our evidence is based on the ab initio many-body calculation of STS images of planar molecules with metal centers. We find that many-body correlations alter significantly the image spectral weight close to the metal center of the molecules. This change is large enough to be accessed experimentally, surviving to molecule-substrate interactions.

  3. Surface structure of YBa2Cu3O7-x probed by reversed-bias scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Edwards, H.L.; Markert, J.T.; Lozanne, A.L.d.

    1994-01-01

    We report the results of scanning tunneling microscopy studies on high-quality single crystals of YBa 2 Cu 3 O 7-x (YBCO) which were cleaved along a basal plane in situ at 20 K prior to measurement. The initial results of a systematic study of the YBCO surface are presented. Reversed-bias images of the CuO chain layer reveal modulations 3.3±0.3|b|=1.3±0.1 nm in wavelength which change phase by 180 degree under bias polarity reversal along solid chains, and are invariant under bias polarity reversal at a point defect. Regions of sharp unit-cell-sized square corrugations with disordered islands are also observed. We interpret these new results in terms of our previous model [H. L. Edwards, J. T. Markert, and A. L. de Lozanne, Phys. Rev. Lett. 69, 2967 (1992)] of the cleaved YBCO surface

  4. Microscopic studies of the fate of charges in organic semiconductors: Scanning Kelvin probe measurements of charge trapping, transport, and electric fields in p- and n-type devices

    Science.gov (United States)

    Smieska, Louisa Marion

    Organic semiconductors could have wide-ranging applications in lightweight, efficient electronic circuits. However, several fundamental questions regarding organic electronic device behavior have not yet been fully addressed, including the nature of chemical charge traps, and robust models for injection and transport. Many studies focus on engineering devices through bulk transport measurements, but it is not always possible to infer the microscopic behavior leading to the observed measurements. In this thesis, we present scanning-probe microscope studies of organic semiconductor devices in an effort to connect local properties with local device behavior. First, we study the chemistry of charge trapping in pentacene transistors. Working devices are doped with known pentacene impurities and the extent of charge trap formation is mapped across the transistor channel. Trap-clearing spectroscopy is employed to measure an excitation of the pentacene charge trap species, enabling identification of the degradationrelated chemical trap in pentacene. Second, we examine transport and trapping in peryelene diimide (PDI) transistors. Local mobilities are extracted from surface potential profiles across a transistor channel, and charge injection kinetics are found to be highly sensitive to electrode cleanliness. Trap-clearing spectra generally resemble PDI absorption spectra, but one derivative yields evidence indicating variation in trap-clearing mechanisms for different surface chemistries. Trap formation rates are measured and found to be independent of surface chemistry, contradicting a proposed silanol trapping mechanism. Finally, we develop a variation of scanning Kelvin probe microscopy that enables measurement of electric fields through a position modulation. This method avoids taking a numeric derivative of potential, which can introduce high-frequency noise into the electric field signal. Preliminary data is presented, and the theoretical basis for electric field

  5. Scanning transmission X-ray microscopy probe for in situ mechanism study of graphene-oxide-based resistive random access memory.

    Science.gov (United States)

    Nho, Hyun Woo; Kim, Jong Yun; Wang, Jian; Shin, Hyun-Joon; Choi, Sung-Yool; Yoon, Tae Hyun

    2014-01-01

    Here, an in situ probe for scanning transmission X-ray microscopy (STXM) has been developed and applied to the study of the bipolar resistive switching (BRS) mechanism in an Al/graphene oxide (GO)/Al resistive random access memory (RRAM) device. To perform in situ STXM studies at the C K- and O K-edges, both the RRAM junctions and the I0 junction were fabricated on a single Si3N4 membrane to obtain local XANES spectra at these absorption edges with more delicate I0 normalization. Using this probe combined with the synchrotron-based STXM technique, it was possible to observe unique chemical changes involved in the BRS process of the Al/GO/Al RRAM device. Reversible oxidation and reduction of GO induced by the externally applied bias voltages were observed at the O K-edge XANES feature located at 538.2 eV, which strongly supported the oxygen ion drift model that was recently proposed from ex situ transmission electron microscope studies.

  6. Near-Field Imaging of Free Carriers in ZnO Nanowires with a Scanning Probe Tip Made of Heavily Doped Germanium

    Science.gov (United States)

    Sakat, Emilie; Giliberti, Valeria; Bollani, Monica; Notargiacomo, Andrea; Pea, Marialilia; Finazzi, Marco; Pellegrini, Giovanni; Hugonin, Jean-Paul; Weber-Bargioni, Alexander; Melli, Mauro; Sassolini, Simone; Cabrini, Stefano; Biagioni, Paolo; Ortolani, Michele; Baldassarre, Leonetta

    2017-11-01

    A novel scanning probe tip made of heavily doped semiconductor is fabricated and used instead of standard gold-coated tips in infrared scattering-type near-field microscopy. Midinfrared near-field microscopy experiments are conducted on ZnO nanowires with a lateral resolution better than 100 nm, using tips made of heavily electron-doped germanium with a plasma frequency in the midinfrared (plasma wavelength of 9.5 μ m ). Nanowires embedded in a dielectric matrix are imaged at two wavelengths, 11.3 and 8.0 μ m , above and below the plasma wavelength of the tips. An opposite sign of the imaging contrasts between the nanowire and the dielectric matrix is observed at the two infrared wavelengths, indicating a clear role of the free-electron plasma in the heavily doped germanium tip in building the imaging contrast. Electromagnetic simulations with a multispherical dipole model accounting for the finite size of the tip are well consistent with the experiments. By comparison of the simulated and measured imaging contrasts, an estimate for the local free-carrier density in the investigated ZnO nanowires in the low 1019 cm-3 range is retrieved. The results are benchmarked against the scattering intensity and phase maps obtained on the same sample with a gold-coated probe tip in pseudoheterodyne detection mode.

  7. Dual-MWCNT Probe Thermal Sensor Assembly and Evaluation Based on Nanorobotic Manipulation inside a Field-Emission-Scanning Electron Microscope

    Directory of Open Access Journals (Sweden)

    Zhan Yang

    2015-03-01

    Full Text Available We report a thermal sensor composed of two multiwalled carbon nano-tubes (MWCNTs inside a field-emission-scanning electron microscope. The sensor was assembled using a nanorobotic manipulation system, which was used to construct a probe tip in order to detect the local environment of a single cell. An atomic force microscopy (AFM cantilever was used as a substrate; the cantilever was composed of Si3N4 and both sides were covered with a gold layer. MWCNTs were individually assembled on both sides of the AFM cantilever by employing nanorobotic manipulation. Another AFM cantilever was subsequently used as an end effector to manipulate the MWCNTs to touch each other. Electron-beam-induced deposition (EBID was then used to bond the two MWCNTs. The MWCNT probe thermal sensor was evaluated inside a thermostated container in the temperature range from 25°C to 60°C. The experimental results show the positive characteristics of the temperature coefficient of resistance (TCR.

  8. Scanning Frequncy Comb Microscopy; a New Tool with Sub-Nm Resolution

    Science.gov (United States)

    Hagmann, Mark; Yarotski, Dmitry

    2016-03-01

    The quasi-periodic excitation of a tunneling junction by a mode-locked ultrafast laser generates a regular sequence of femtosecond pulses of electrons at the pulse repetition rate fR of the laser to be superimposed on the dc tunneling current. In the frequency domain this is equivalent to a microwave frequency comb (MFC) of harmonics at integer multiples of fR. Using a metal tip and sample in a scanning tunneling microscope and a mode-locked Ti:Sapphire laser with a fR of 74.254 MHz, the 200th harmonic at 14.85 GHz has a signal-to-noise ratio of 20 dB, and a linewidth art for narrow-linewidth in a microwave source. The decay in the amplitude of the harmonics with increasing frequency corresponds to a time constant of 320 ps which is attributed to 6.4 pF of shunting capacitance near the junction and the 50 Ω load of the spectrum analyzer. Spreading resistance in semiconductor samples causes the measured attenuation to be sensitive to the local concentration of the carriers. The laser photon energy must be less than the bandgap energy to prevent the creation of electron-hole pairs which would cause surge currents that interfere with the measurements. 2880 S. Main Street #214, Salt Lake City, Utah 84115, USA.

  9. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales.

    Science.gov (United States)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A L David; Belcher, Warwick J; Dastoor, Paul C

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  10. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    Science.gov (United States)

    Burke, Kerry B.; Stapleton, Andrew J.; Vaughan, Ben; Zhou, Xiaojing; Kilcoyne, A. L. David; Belcher, Warwick J.; Dastoor, Paul C.

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N'-(4-butylphenyl)-bis-N, N'-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  11. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    International Nuclear Information System (INIS)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C; Kilcoyne, A L David

    2011-01-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N ' -(4-butylphenyl)-bis-N, N ' -phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  12. Scanning transmission x-ray microscopy of polymer nanoparticles: probing morphology on sub-10 nm length scales

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Kerry B; Stapleton, Andrew J; Vaughan, Ben; Zhou Xiaojing; Belcher, Warwick J; Dastoor, Paul C [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia); Kilcoyne, A L David, E-mail: Paul.Dastoor@newcastle.edu.au [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2011-07-01

    Water-processable nanoparticle dispersions of semiconducting polymers offer an attractive approach to the fabrication of organic electronic devices since they offer: (1) control of nanoscale morphology and (2) environmentally friendly fabrication. Although the nature of phase segregation in these polymer nanoparticles is critical to device performance, to date there have been no techniques available to directly determine their intra-particle structure, which consequently has been poorly understood. Here, we present scanning transmission x-ray microscopy (STXM) compositional maps for nanoparticles fabricated from poly(9,9-dioctyl-fluorene-2,7-diyl-co-bis-N, N{sup '}-(4-butylphenyl)-bis-N, N{sup '}-phenyl-1,4-phenylenedi-amine) (PFB) and poly(9,9-dioctylfluorene-2,7-diyl-co-benzothiadiazole) (F8BT) 1:1 blend mixtures. The images show distinct phase segregation within the nanoparticles. The compositional data reveals that, within these nanoparticles, PFB and F8BT segregate into a core-shell morphology, with an F8BT-rich core and a PFB-rich shell. Structural modelling demonstrates that the STXM technique is capable of quantifying morphological features on a sub-10 nm length scale; below the spot size of the incident focused x-ray beam. These results have important implications for the development of water-based 'solar paints' fabricated from microemulsions of semiconducting polymers.

  13. Investigation of Electron Transport Across Vertically Grown CNTs Using Combination of Proximity Field Emission Microscopy and Scanning Probe Image Processing Techniques

    KAUST Repository

    Kolekar, Sadhu

    2018-02-26

    Field emission from nanostructured films is known to be dominated by only small number of localized spots which varies with the voltage, electric field and heat treatment. It is important to develop processing methods which will produce stable and uniform emitting sites. In this paper we report a novel approach which involves analysis of Proximity Field Emission Microscopic (PFEM) images using Scanning Probe Image Processing technique. Vertically aligned carbon nanotube emitters have been deposited on tungsten foil by water assisted chemical vapor deposition. Prior to the field electron emission studies, these films were characterized by scanning electron microscopy, transmission electron microscopy, and Atomic Force Microscopy (AFM). AFM images of the samples show bristle like structure, the size of bristle varying from 80 to 300 nm. The topography images were found to exhibit strong correlation with current images. Current–Voltage (I–V) measurements both from Scanning Tunneling Microscopy and Conducting-AFM mode suggest that electron transport mechanism in imaging vertically grown CNTs is ballistic rather than usual tunneling or field emission with a junction resistance of ~10 kΩ. It was found that I–V curves for field emission mode in PFEM geometry vary initially with number of I–V cycles until reproducible I–V curves are obtained. Even for reasonably stable I–V behavior the number of spots was found to increase with the voltage leading to a modified Fowler–Nordheim (F–N) behavior. A plot of ln(I/V3) versus 1/V was found to be linear. Current versus time data exhibit large fluctuation with the power spectral density obeying 1/f2 law. It is suggested that an analogue of F–N equation of the form ln(I/Vα) versus 1/V may be used for the analysis of field emission data, where α may depend on nanostructure configuration and can be determined from the dependence of emitting spots on the voltage.Graphical Abstract

  14. Investigation of Electron Transport Across Vertically Grown CNTs Using Combination of Proximity Field Emission Microscopy and Scanning Probe Image Processing Techniques

    Science.gov (United States)

    Kolekar, Sadhu; Patole, Shashikant P.; Yoo, Ji-Beom; Dharmadhikari, Chandrakant V.

    2018-03-01

    Field emission from nanostructured films is known to be dominated by only small number of localized spots which varies with the voltage, electric field and heat treatment. It is important to develop processing methods which will produce stable and uniform emitting sites. In this paper we report a novel approach which involves analysis of Proximity Field Emission Microscopic (PFEM) images using Scanning Probe Image Processing technique. Vertically aligned carbon nanotube emitters have been deposited on tungsten foil by water assisted chemical vapor deposition. Prior to the field electron emission studies, these films were characterized by scanning electron microscopy, transmission electron microscopy, and Atomic Force Microscopy (AFM). AFM images of the samples show bristle like structure, the size of bristle varying from 80 to 300 nm. The topography images were found to exhibit strong correlation with current images. Current-Voltage (I-V) measurements both from Scanning Tunneling Microscopy and Conducting-AFM mode suggest that electron transport mechanism in imaging vertically grown CNTs is ballistic rather than usual tunneling or field emission with a junction resistance of 10 kΩ. It was found that I-V curves for field emission mode in PFEM geometry vary initially with number of I-V cycles until reproducible I-V curves are obtained. Even for reasonably stable I-V behavior the number of spots was found to increase with the voltage leading to a modified Fowler-Nordheim (F-N) behavior. A plot of ln(I/V3) versus 1/V was found to be linear. Current versus time data exhibit large fluctuation with the power spectral density obeying 1/f2 law. It is suggested that an analogue of F-N equation of the form ln(I/Vα) versus 1/V may be used for the analysis of field emission data, where α may depend on nanostructure configuration and can be determined from the dependence of emitting spots on the voltage.

  15. Zeeman effect in sulfur monoxide. A tool to probe magnetic fields in star forming regions

    Science.gov (United States)

    Cazzoli, Gabriele; Lattanzi, Valerio; Coriani, Sonia; Gauss, Jürgen; Codella, Claudio; Ramos, Andrés Asensio; Cernicharo, José; Puzzarini, Cristina

    2017-09-01

    Context. Magnetic fields play a fundamental role in star formation processes and the best method to evaluate their intensity is to measure the Zeeman effect of atomic and molecular lines. However, a direct measurement of the Zeeman spectral pattern from interstellar molecular species is challenging due to the high sensitivity and high spectral resolution required. So far, the Zeeman effect has been detected unambiguously in star forming regions for very few non-masing species, such as OH and CN. Aims: We decided to investigate the suitability of sulfur monoxide (SO), which is one of the most abundant species in star forming regions, for probing the intensity of magnetic fields via the Zeeman effect. Methods: We investigated the Zeeman effect for several rotational transitions of SO in the (sub-)mm spectral regions by using a frequency-modulated, computer-controlled spectrometer, and by applying a magnetic field parallel to the radiation propagation (I.e., perpendicular to the oscillating magnetic field of the radiation). To support the experimental determination of the g factors of SO, a systematic quantum-chemical investigation of these parameters for both SO and O2 has been carried out. Results: An effective experimental-computational strategy for providing accurate g factors as well as for identifying the rotational transitions showing the strongest Zeeman effect has been presented. Revised g factors have been obtained from a large number of SO rotational transitions between 86 and 389 GHz. In particular, the rotational transitions showing the largest Zeeman shifts are: N,J = 2, 2 ← 1, 1 (86.1 GHz), N,J = 4, 3 ← 3, 2 (159.0 GHz), N,J = 1, 1 ← 0, 1 (286.3 GHz), N,J = 2, 2 ← 1, 2 (309.5 GHz), and N,J = 2, 1 ← 1, 0 (329.4 GHz). Our investigation supports SO as a good candidate for probing magnetic fields in high-density star forming regions. The complete list of measured Zeeman components is only available at the CDS via anonymous ftp to http

  16. New LWD tools are just in time to probe for baby elephants

    Energy Technology Data Exchange (ETDEWEB)

    Ghiselin, D.

    1997-04-01

    Development of sophisticated formation evaluation instrumentation for use while drilling has led to a stratification of while-drilling services. Measurements while drilling (MWD) comprises measurements of mechanical parameters like weight-on-bit, mud pressures, torque, vibration, hole angle and direction. Logging while drilling (LWD) describes resistivity, sonic, and radiation logging which rival wireline measurements in accuracy. A critical feature of LWD is the rate that data can be telemetered to the surface. Early tools could only transmit 3 bits per second one way. In the last decade, the data rate has more than tripled. Despite these improvements, LWD tools have the ability to make many more measurements than can be telemetered in real-time. The paper discusses the development of this technology and its applications.

  17. Polarization entanglement of sum-frequency photons: A tool to probe the Markovian limit

    Science.gov (United States)

    Volkov, Victor; Chelli, Riccardo

    2015-06-01

    The article addresses the possibility of entanglement-specific infrared-visible sum-frequency generation spectroscopy. In the case of an anisotropic interface, it is possible to employ SSS and PSS polarizations to detect responses not only specific to χY Y Y and χX Y Y nonlinearities, but also to higher-order χ(Y Y Y )(X Y Y ) and χ(X Y Y )(Y Y Y ) nonlinearities. Using quantum mechanical studies of the rhenium complex [Re (OH) 3(CO) 3] as a molecular model, we demonstrate that if such complexes would form an anisotropic orientational distribution at a surface, under the considered geometry and the polarization settings, we may prepare quantum correlated C =O vibrational states to emit polarization-entangled photons. Accordingly, we explore the possibility of a polarization-measurement protocol to extract spectral signatures of the entangled states. The response would be informative on intramolecular interactions. As a result, we discuss the possible practical implications in probing dynamics at interfaces, and different opportunities in the preparation of entangled vibrational states of quantified fidelity.

  18. Fluorescent probes as a tool for labelling and tracking the amphibian chytrid fungus Batrachochytrium dendrobatidis.

    Science.gov (United States)

    Herbert, Sarah M; Leung, Tommy L F; Bishop, Phillip J

    2011-09-09

    The dissemination of the virulent pathogen Batrachochytrium dendrobatidis (Bd) has contributed to the decline and extinction of many amphibian species worldwide. Several different strains have been identified, some of which are sympatric. Interactions between co-infecting strains of a pathogen can have significant influences on disease epidemiology and evolution; therefore the dynamics of multi-strain infections is an important area of research. We stained Bd cells with 2 fluorescent BODIPY fatty acid probes to determine whether these can potentially be used to distinguish and track Bd cell lines in multi-strain experiments. Bd cells in broth culture were stained with 5 concentrations of green-fluorescent BODIPY FL and red-fluorescent BODIPY 558/568 and visualised under an epifluorescent microscope for up to 16 d post-dye. Dyed strains were also assessed for growth inhibition. The most effective concentration for both dyes was 10 pM. This concentration of dye produced strong fluorescence for 12 to 16 d in Bd cultures held at 23 degrees C (3 to 4 generations), and did not inhibit Bd growth. Cells dyed with BODIPY FL and BODIPY 558/568 can be distinguished from each other on the basis of their fluorescence characteristics. Therefore, it is likely that this technique will be useful for research into multi-strain dynamics of Bd infections.

  19. Clinical efficacy of FDG-PET scan as preoperative diagnostic tool in cervical cancer stage Ib and IIa: comparison between the results of FDG-PET scan and operative findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Hoon

    1999-12-01

    This study was done to evaluate the clinical feasibility of FDG-PET scan for routine preoperative diagnostic methods in cervical carcinoma. PET-scans were performed from March, 1999 to November, 1999. There were 6 stage Ib and 7 IIa patients and all patients were performed radical hysterectomy and bilateral pelvic lymph node dissections and were evaluated by FDG-PET scan before operation. The mean age of the patients were 50.3 years old. Six cases had lymph node metastases by pelvis MRI, and three cases by FDG-PET scan. We could not find any lymph node metastases at surgery in 3 patients (50.0%) among 6 patients who were diagnosed by nodal metastases by pelvis MRI. And we found 1 patients with nodal metastases who had negative findings by pelvis MRI. By FDG-PET scan, we could find metastases in all positive patients. But we also found 2 additional metastatic cases in the patients with negative findings. In this study, the comparison was very difficult due to the individual differences in the comparison would be made by site-specific not person. The sensitivity of MRI and FDG-PET scan were 50.0% and 30.0%. The specificity were 94.1 % and 95.6%. The positive predictive value were 55.6 % and 50.0 %. In conclusion, we could find any superiority of FDG-PET scan in the diagnosis of lymph node metastases the pelvis MRI. So there are limitations to use the FDG-PET scan in the routine preoperative diagnostic tools in cervical cancer. But if we have more experiences to use the FDG-PET scan such as precise cut-off value of SUV and combination of other imaging technique, the FDG-PET scan are still promising diagnostic tools in cervical cancer.

  20. Servo scanning 3D micro EDM for array micro cavities using on-machine fabricated tool electrodes

    Science.gov (United States)

    Tong, Hao; Li, Yong; Zhang, Long

    2018-02-01

    Array micro cavities are useful in many fields including in micro molds, optical devices, biochips and so on. Array servo scanning micro electro discharge machining (EDM), using array micro electrodes with simple cross-sectional shape, has the advantage of machining complex 3D micro cavities in batches. In this paper, the machining errors caused by offline-fabricated array micro electrodes are analyzed in particular, and then a machining process of array servo scanning micro EDM is proposed by using on-machine fabricated array micro electrodes. The array micro electrodes are fabricated on-machine by combined procedures including wire electro discharge grinding, array reverse copying and electrode end trimming. Nine-array tool electrodes with Φ80 µm diameter and 600 µm length are obtained. Furthermore, the proposed process is verified by several machining experiments for achieving nine-array hexagonal micro cavities with top side length of 300 µm, bottom side length of 150 µm, and depth of 112 µm or 120 µm. In the experiments, a chip hump accumulates on the electrode tips like the built-up edge in mechanical machining under the conditions of brass workpieces, copper electrodes and the dielectric of deionized water. The accumulated hump can be avoided by replacing the water dielectric by an oil dielectric.

  1. Helium Ion Microscopy: A Promising Tool for Probing Biota-Mineral Interfaces

    Science.gov (United States)

    Lybrand, R.; Zaharescu, D. G.; Gallery, R. E.

    2017-12-01

    The study of biogeochemical interfaces in soil requires powerful technologies that can enhance our ability to characterize mineral surfaces and interacting organisms at micro- to nanoscale resolutions. We aim to demonstrate potential applications of Helium Ion Microscopy in the earth and ecological sciences using, as an example, samples from a field experiment. We assessed samples deployed for one year along climatic and topographic gradients in two Critical Zone Observatories (CZOs): a desert to mixed conifer forest gradient (Catalina CZO) and a humid hardwood forest (Calhoun CZO). Sterile ground rock (basalt, quartz, and granite; 53-250 µm) was sealed into nylon mesh bags and buried in the surface soils of both CZOs. We employed helium ion and scanning electron microscopies to compare retrieved ground rock samples with sterile unreacted mineral controls in conjunction with the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory, USA. Our work showed early colonization of mesh bag materials by fungal and bacterial organisms from the field systems and identified morphological changes in mineral grains following exposure to the soil environment. Biological specimens observed on grain surfaces exhibited contrasting features depending on mineral type and ecosystem location, including fungal hyphae that varied in length, diameter, and surface morphologies. We also present imagery that provides evidence for incipient stages of mineral transformation at the fungal-mineral interface. Our findings demonstrate that helium ion microscopy can be successfully used to characterize grain features and biological agents of weathering in experimental field samples, representing a promising avenue for research in the biogeosciences. Future directions of this work will couple high resolution imaging with measures of aqueous and solid geochemistry, fungal morphological characterization, and microbial profiling to better understand mineral

  2. Detailed characterisation of focused ion beam induced lateral damage on silicon carbide samples by electrical scanning probe microscopy and transmission electron microscopy

    Science.gov (United States)

    Stumpf, F.; Abu Quba, A. A.; Singer, P.; Rumler, M.; Cherkashin, N.; Schamm-Chardon, S.; Cours, R.; Rommel, M.

    2018-03-01

    The lateral damage induced by focused ion beam on silicon carbide was characterized using electrical scanning probe microscopy (SPM), namely, scanning spreading resistance microscopy and conductive atomic force microscopy (c-AFM). It is shown that the damage exceeds the purposely irradiated circles with a radius of 0.5 μm by several micrometres, up to 8 μm for the maximum applied ion dose of 1018 cm-2. Obtained SPM results are critically compared with earlier findings on silicon. For doses above the amorphization threshold, in both cases, three different areas can be distinguished. The purposely irradiated area exhibits resistances smaller than the non-affected substrate. A second region with strongly increasing resistance and a maximum saturation value surrounds it. The third region shows the transition from maximum resistance to the base resistance of the unaffected substrate. It correlates to the transition from amorphized to defect-rich to pristine crystalline substrate. Additionally, conventional transmission electron microscopy (TEM) and annular dark-field STEM were used to complement and explain the SPM results and get a further understanding of the defect spreading underneath the surface. Those measurements also show three different regions that correlate well with the regions observed from electrical SPM. TEM results further allow to explain observed differences in the electrical results for silicon and silicon carbide which are most prominent for ion doses above 3 × 1016 cm-2. Furthermore, the conventional approach to perform current-voltage measurements by c-AFM was critically reviewed and several improvements for measurement and analysis process were suggested that result in more reliable and impactful c-AFM data.

  3. Comparison of 3D cellular imaging techniques based on scanned electron probes: Serial block face SEM vs. Axial bright-field STEM tomography.

    Science.gov (United States)

    McBride, E L; Rao, A; Zhang, G; Hoyne, J D; Calco, G N; Kuo, B C; He, Q; Prince, A A; Pokrovskaya, I D; Storrie, B; Sousa, A A; Aronova, M A; Leapman, R D

    2018-06-01

    Microscopies based on focused electron probes allow the cell biologist to image the 3D ultrastructure of eukaryotic cells and tissues extending over large volumes, thus providing new insight into the relationship between cellular architecture and function of organelles. Here we compare two such techniques: electron tomography in conjunction with axial bright-field scanning transmission electron microscopy (BF-STEM), and serial block face scanning electron microscopy (SBF-SEM). The advantages and limitations of each technique are illustrated by their application to determining the 3D ultrastructure of human blood platelets, by considering specimen geometry, specimen preparation, beam damage and image processing methods. Many features of the complex membranes composing the platelet organelles can be determined from both approaches, although STEM tomography offers a higher ∼3 nm isotropic pixel size, compared with ∼5 nm for SBF-SEM in the plane of the block face and ∼30 nm in the perpendicular direction. In this regard, we demonstrate that STEM tomography is advantageous for visualizing the platelet canalicular system, which consists of an interconnected network of narrow (∼50-100 nm) membranous cisternae. In contrast, SBF-SEM enables visualization of complete platelets, each of which extends ∼2 µm in minimum dimension, whereas BF-STEM tomography can typically only visualize approximately half of the platelet volume due to a rapid non-linear loss of signal in specimens of thickness greater than ∼1.5 µm. We also show that the limitations of each approach can be ameliorated by combining 3D and 2D measurements using a stereological approach. Copyright © 2018. Published by Elsevier Inc.

  4. Power spectra as a diagnostic tool in probing statistical/nonstatistical behavior in unimolecular reactions

    Science.gov (United States)

    Chang, Xiaoyen Y.; Sewell, Thomas D.; Raff, Lionel M.; Thompson, Donald L.

    1992-11-01

    The possibility of utilizing different types of power spectra obtained from classical trajectories as a diagnostic tool to identify the presence of nonstatistical dynamics is explored by using the unimolecular bond-fission reactions of 1,2-difluoroethane and the 2-chloroethyl radical as test cases. In previous studies, the reaction rates for these systems were calculated by using a variational transition-state theory and classical trajectory methods. A comparison of the results showed that 1,2-difluoroethane is a nonstatistical system, while the 2-chloroethyl radical behaves statistically. Power spectra for these two systems have been generated under various conditions. The characteristics of these spectra are as follows: (1) The spectra for the 2-chloroethyl radical are always broader and more coupled to other modes than is the case for 1,2-difluoroethane. This is true even at very low levels of excitation. (2) When an internal energy near or above the dissociation threshold is initially partitioned into a local C-H stretching mode, the power spectra for 1,2-difluoroethane broaden somewhat, but discrete and somewhat isolated bands are still clearly evident. In contrast, the analogous power spectra for the 2-chloroethyl radical exhibit a near complete absence of isolated bands. The general appearance of the spectrum suggests a very high level of mode-to-mode coupling, large intramolecular vibrational energy redistribution (IVR) rates, and global statistical behavior. (3) The appearance of the power spectrum for the 2-chloroethyl radical is unaltered regardless of whether the initial C-H excitation is in the CH2 or the CH2Cl group. This result also suggests statistical behavior. These results are interpreted to mean that power spectra may be used as a diagnostic tool to assess the statistical character of a system. The presence of a diffuse spectrum exhibiting a nearly complete loss of isolated structures indicates that the dissociation dynamics of the molecule will

  5. Design of a scanning probe microscope with advanced sample treatment capabilities: An atomic force microscope combined with a miniaturized inductively coupled plasma source

    International Nuclear Information System (INIS)

    Hund, Markus; Herold, Hans

    2007-01-01

    We describe the design and performance of an atomic force microscope (AFM) combined with a miniaturized inductively coupled plasma source working at a radio frequency of 27.12 MHz. State-of-the-art scanning probe microscopes (SPMs) have limited in situ sample treatment capabilities. Aggressive treatments such as plasma etching or harsh treatments such as etching in aggressive liquids typically require the removal of the sample from the microscope. Consequently, time consuming procedures are required if the same sample spot has to be imaged after successive processing steps. We have developed a first prototype of a SPM which features a quasi in situ sample treatment using a modified commercial atomic force microscope. A sample holder is positioned in a special reactor chamber; the AFM tip can be retracted by several millimeters so that the chamber can be closed for a treatment procedure. Most importantly, after the treatment, the tip is moved back to the sample with a lateral drift per process step in the 20 nm regime. The performance of the prototype is characterized by consecutive plasma etching of a nanostructured polymer film

  6. New Algorithm to Enable Construction and Display of 3D Structures from Scanning Probe Microscopy Images Acquired Layer-by-Layer.

    Science.gov (United States)

    Deng, William Nanqiao; Wang, Shuo; Ventrici de Souza, Joao Francisco; Kuhl, Tonya L; Liu, Gang-Yu

    2018-06-11

    Scanning probe microscopy (SPM) such as atomic force microscopy (AFM) is widely known for high-resolution imaging of surface structures and nanolithography in two dimension (2D), which provides important physical insights in surface science and material science. This work reports a new algorithm to enable construction and display of layer-by-layer 3D structures from SPM images. The algorithm enables alignment of SPM images acquired during layer-by-layer deposition, removal of redundant features, and faithfully constructs the deposited 3D structures. The display uses a "see-through" strategy to enable the structure of each layer to be visible. The results demonstrate high spatial accuracy as well as algorithm versatility; users can set parameters for reconstruction and display as per image quality and research needs. To the best of our knowledge, this method represents the first report to enable SPM technology for 3D imaging construction and display. The detailed algorithm is provided to facilitate usage of the same approach in any SPM software. These new capabilities support wide applications of SPM that require 3D image reconstruction and display, such as 3D nanoprinting, and 3D additive and subtractive manufacturing and imaging.

  7. Combined scanning probe and light scattering characterization of multi-stage self-assembly of targeted liposome-based delivery systems

    International Nuclear Information System (INIS)

    Farkas, N; Dagata, J A; Yang, C; Rait, A; Pirollo, K F; Chang, E H

    2011-01-01

    The mean size and size distribution of a targeted nanoparticle delivery system (NDS) strongly influences the intrinsic stability and functionality of this molecular complex, affects its performance as a systemic drug delivery platform and ultimately determines its efficacy toward early detection and treatment of cancer. Since its components undergo significant reorganization during multiple stages of self-assembly, it is essential to monitor the size and stability of the complex throughout the NDS formulation in order to ensure its potency and manufacturability prior to entering clinical trials. This work combines scanning probe microscopy (SPM) and dynamic light scattering (DLS) techniques to obtain quantitative and reliable size measurements of the NDS, and to investigate how variations in the NDS formulation or self-assembly process impact the size, structure and functionality of the complex with various therapeutic and diagnostic agent payloads. These combined SPM and DLS methods, when implemented at an early stage of the NDS formulation, present a potential measurement approach to facilitate drug discovery and development, optimization and quality control during manufacturing of the NDS

  8. Scanning vector Hall probe microscope

    Czech Academy of Sciences Publication Activity Database

    Fedor, J.; Cambel, V.; Gregušová, D.; Hanzelka, Pavel; Dérer, J.; Volko, J.

    2003-01-01

    Roč. 74, č. 12 (2003), s. 5105 - 5110 ISSN 0034-6748 Institutional research plan: CEZ:AV0Z2065902 Keywords : VHPM * Hall sensor * Helium cryostat Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.343, year: 2003 http://web. ebscohost .com/ehost/pdf?vid=8&hid=115&sid=a7c0555a-21f4-4932-b1c6-a308ac4dd50b%40sessionmgr2

  9. EEG, CT scan and MRI as diagnostic tools for ADHD in population between 6 and 19 years: a systematic review

    Directory of Open Access Journals (Sweden)

    José Calleja

    2012-09-01

    Full Text Available Introduction: Attention deficit and hyperactivity disorder (ADHD is generally diagnosed based on the criteria of DSM-IV. Because several diagnostic tests have appeared such as electroencephalography (EEG, CT scan and magnetic resonance imaging (MRI, there is a particular interest in determining the usefulness and diagnostic accuracy of these tests for the diagnosis of ADHD. Purpose: To identify, synthesize and evaluate the best available evidence on the usefulness of EEG, CT and MRI as a diagnostic tool in ADHD in the 6-19 year-old population. Methods: A systematic review of studies on diagnostic tests that assessed the validity, reliability and effectiveness of the implementation of EEG, CT and MRI in the diagnosis of ADHD in the 6-19 year-old population was conducted. Searches were done in PubMed/MEDLINE, LILACS, Cochrane, DARE and National Guideline Clearinghouse databases, until February 2012, in English and Spanish. The articles that met the inclusion criteria were independently assessed by two investigators for methodological quality using standard checklists for review articles and diagnostic test articles. Results: Of the 115 studies found, eight studies were included, among which two medium-quality systematic reviews and a good-quality primary article on diagnostic tests. Additionally, five evidence-based clinical guidelines that address this issue were also included. Conclusions: The available evidence on the validity, reliability and effectiveness of the electroencephalogram, computed tomography and magnetic resonance imaging, does not recommend their use as diagnostic tools for ADHD. Clinical practice guidelines do not recommend their use either. These tests are recommended for the assessment of the individual patient with the disorder.

  10. Portable optical fiber probe-based spectroscopic scanner for rapid cancer diagnosis: a new tool for intraoperative margin assessment.

    Directory of Open Access Journals (Sweden)

    Niyom Lue

    Full Text Available There continues to be a significant clinical need for rapid and reliable intraoperative margin assessment during cancer surgery. Here we describe a portable, quantitative, optical fiber probe-based, spectroscopic tissue scanner designed for intraoperative diagnostic imaging of surgical margins, which we tested in a proof of concept study in human tissue for breast cancer diagnosis. The tissue scanner combines both diffuse reflectance spectroscopy (DRS and intrinsic fluorescence spectroscopy (IFS, and has hyperspectral imaging capability, acquiring full DRS and IFS spectra for each scanned image pixel. Modeling of the DRS and IFS spectra yields quantitative parameters that reflect the metabolic, biochemical and morphological state of tissue, which are translated into disease diagnosis. The tissue scanner has high spatial resolution (0.25 mm over a wide field of view (10 cm × 10 cm, and both high spectral resolution (2 nm and high spectral contrast, readily distinguishing tissues with widely varying optical properties (bone, skeletal muscle, fat and connective tissue. Tissue-simulating phantom experiments confirm that the tissue scanner can quantitatively measure spectral parameters, such as hemoglobin concentration, in a physiologically relevant range with a high degree of accuracy (<5% error. Finally, studies using human breast tissues showed that the tissue scanner can detect small foci of breast cancer in a background of normal breast tissue. This tissue scanner is simpler in design, images a larger field of view at higher resolution and provides a more physically meaningful tissue diagnosis than other spectroscopic imaging systems currently reported in literatures. We believe this spectroscopic tissue scanner can provide real-time, comprehensive diagnostic imaging of surgical margins in excised tissues, overcoming the sampling limitation in current histopathology margin assessment. As such it is a significant step in the development of a

  11. Ultrasonic simulation - Imagine3D and SimScan: Tools to solve the inverse problem for complex turbine components

    International Nuclear Information System (INIS)

    Mair, H.D.; Ciorau, P.; Owen, D.; Hazelton, T.; Dunning, G.

    2000-01-01

    Two ultrasonic simulation packages: Imagine 3D and SIMSCAN have specifically been developed to solve the inverse problem for blade root and rotor steeple of low-pressure turbine. The software was integrated with the 3D drawing of the inspected parts, and with the dimensions of linear phased-array probes. SIMSCAN simulates the inspection scenario in both optional conditions: defect location and probe movement/refracted angle range. The results are displayed into Imagine 3-D, with a variety of options: rendering, display 1:1, grid, generated UT beam. The results are very useful for procedure developer, training and to optimize the phased-array probe inspection sequence. A spreadsheet is generated to correlate the defect coordinates with UT data (probe position, skew and refracted angle, UT path, and probe movement). The simulation models were validated during experimental work with phased-array systems. The accuracy in probe position is ±1 mm, and the refracted/skew angle is within ±0.5 deg. . Representative examples of phased array focal laws/probe movement for a specific defect location, are also included

  12. Direct comparison of the FibroScan XL and M probes for assessment of liver fibrosis in obese and nonobese patients

    Directory of Open Access Journals (Sweden)

    Durango E

    2013-07-01

    Full Text Available Esteban Durango,1,* Christian Dietrich,1,* Helmut Karl Seitz,1 Cornelia Ursula Kunz,2 Gilles T Pomier-Layrargues,3 Andres Duarte-Rojo,4 Melanie Beaton,5 Magdy Elkhashab,6 Robert P Myers,7 Sebastian Mueller1,3 1Department of Medicine and Center for Alcohol Research, Liver Disease and Nutrition, Salem Medical Center, 2Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany; 3Liver Unit, Centre Hospitalier de l'Université de Montréal, Hôpital Saint-Luc, Montréal, Quebec, 4Toronto Western Hospital Liver Centre, Toronto, Ontario; 5Multi-Organ Transplant Unit, University of Western Ontario, London, Ontario; 6The Toronto Liver Centre, Toronto, Ontario; 7Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada *These authors contributed equally to this researchBackground: A novel Fibroscan XL probe has recently been introduced and validated for obese patients, and has a diagnostic accuracy comparable with that of the standard M probe. The aim of this study was to analyze and understand the differences between these two probes in nonobese patients, to identify underlying causes for these differences, and to develop a practical algorithm to translate results for the XL probe to those for the M probe.Methods and results: Both probes were directly compared first in copolymer phantoms of varying stiffness (4.8, 11, and 40 kPa and then in 371 obese and nonobese patients (body mass index, range 17.2–72.4 from German (n = 129 and Canadian (n = 242 centers. Liver stiffness values for both probes correlated better in phantoms than in patients (r = 0.98 versus 0.82, P 10 kPa for F0, F1–2, F3, and F4 fibrosis, respectively significantly improved agreement between the two probes from r = 0.655 to 0.679.Conclusion: Liver stiffness can be measured in significantly more obese and nonobese patients using the XL probe than the M probe. However, the XL

  13. Metabolite profiling with HPLC-ICP-MS as a tool for in vivo characterization of imaging probes.

    Science.gov (United States)

    Boros, Eszter; Pinkhasov, Omar R; Caravan, Peter

    2018-01-01

    Current analytical methods for characterizing pharmacokinetic and metabolic properties of positron emission tomography (PET) and single photon emission computed tomography (SPECT) probes are limited. Alternative methods to study tracer metabolism are needed. The study objective was to assess the potential of high performance liquid chromatography - inductively coupled plasma - mass spectrometry (HPLC-ICP-MS) for quantification of molecular probe metabolism and pharmacokinetics using stable isotopes. Two known peptide-DOTA conjugates were chelated with nat Ga and nat In. Limit of detection of HPLC-ICP-MS for 69 Ga and 115 In was determined. Rats were administered 50-150 nmol of Ga- and/or In-labeled probes, blood was serially sampled, and plasma analyzed by HPLC-ICP-MS using both reverse phase and size exclusion chromatography. The limits of detection were 0.16 pmol for 115 In and 0.53 pmol for 69 Ga. Metabolites as low as 0.001 %ID/g could be detected and transchelation products identified. Simultaneous administration of Ga- and In-labeled probes allowed the determination of pharmacokinetics and metabolism of both probes in a single animal. HPLC-ICP-MS is a robust, sensitive and radiation-free technique to characterize the pharmacokinetics and metabolism of imaging probes.

  14. The Use of 3D Scanning Methods to Evaluate the Hybrid Layer Used in Forging Tools in Order to Improve their Durability

    Directory of Open Access Journals (Sweden)

    Gronostajski Z.

    2017-09-01

    Full Text Available This study is focused on tools used in the industrial process of hot forging of a front wheel forging (gear wheel manufactured for the automotive industry. Five different variants were applied for the tools: 3 die inserts were coated with three different hybrid layers (PN + PVD type, i.e. AlCrTiN, AlCrTiSiN and CrN, one insert was only nitrided, and one was pad welded, to improve tool durability. The tool wear was analysed and represented by the material degradation on the working surface, based on the 3D scanning and the material growth of the periodically collected forgings. Additionally, the scanned tools were divided into two areas, in which it was found, based on the analysis, that various degradation mechanisms are predominant. Microstructural tests and hardness measurements of the analyzed tools were also performed. Based on the results, it was found that, in the central part of the die insert, thermo-mechanical fatigue, abrasive wear and plastic deformation occurred, while in the area of the bridge insert, only abrasive wear could be observed. For these areas, the loss of material was determined separately. It was established that the use of the GN+CrN and GN+AlCrTiN hybrid layers on forging tools improves their durability, while the best results in the central area were observed on the tool with the GN+CrN layer, which is the most resistant to thermo-mechanical fatigue. In the second analyzed area, good wear resistance occurred on GN+CrN, GN+AlCrTiN and pad welded inserts, for which, together with the increase of the forging number, a proportional, slight growth of the loss of material occurred.

  15. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    Energy Technology Data Exchange (ETDEWEB)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian [University Hospital Essen, Institute of Diagnostic and Interventional Radiology and Neuroradiology, Essen (Germany)

    2016-10-15

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

  16. Coupling scanning tunneling microscope and supersonic molecular beams: a unique tool for in situ investigation of the morphology of activated systems.

    Science.gov (United States)

    Smerieri, M; Reichelt, R; Savio, L; Vattuone, L; Rocca, M

    2012-09-01

    We report here on a new experimental apparatus combining a commercial low temperature scanning tunneling microscope with a supersonic molecular beam. This setup provides a unique tool for the in situ investigation of the topography of activated adsorption systems and opens thus new interesting perspectives. It has been tested towards the formation of the O/Ag(110) added rows reconstruction and of their hydroxylation, comparing data recorded upon O(2) exposure at thermal and hyperthermal energies.

  17. Clinical evaluation of a dose monitoring software tool based on Monte Carlo Simulation in assessment of eye lens doses for cranial CT scans

    International Nuclear Information System (INIS)

    Guberina, Nika; Suntharalingam, Saravanabavaan; Nassenstein, Kai; Forsting, Michael; Theysohn, Jens; Wetter, Axel; Ringelstein, Adrian

    2016-01-01

    The aim of this study was to verify the results of a dose monitoring software tool based on Monte Carlo Simulation (MCS) in assessment of eye lens doses for cranial CT scans. In cooperation with the Federal Office for Radiation Protection (Neuherberg, Germany), phantom measurements were performed with thermoluminescence dosimeters (TLD LiF:Mg,Ti) using cranial CT protocols: (I) CT angiography; (II) unenhanced, cranial CT scans with gantry angulation at a single and (III) without gantry angulation at a dual source CT scanner. Eye lens doses calculated by the dose monitoring tool based on MCS and assessed with TLDs were compared. Eye lens doses are summarized as follows: (I) CT angiography (a) MCS 7 mSv, (b) TLD 5 mSv; (II) unenhanced, cranial CT scan with gantry angulation, (c) MCS 45 mSv, (d) TLD 5 mSv; (III) unenhanced, cranial CT scan without gantry angulation (e) MCS 38 mSv, (f) TLD 35 mSv. Intermodality comparison shows an inaccurate calculation of eye lens doses in unenhanced cranial CT protocols at the single source CT scanner due to the disregard of gantry angulation. On the contrary, the dose monitoring tool showed an accurate calculation of eye lens doses at the dual source CT scanner without gantry angulation and for CT angiography examinations. The dose monitoring software tool based on MCS gave accurate estimates of eye lens doses in cranial CT protocols. However, knowledge of protocol and software specific influences is crucial for correct assessment of eye lens doses in routine clinical use. (orig.)

  18. SINE_scan: an efficient tool to discover short interspersed nuclear elements (SINEs) in large-scale genomic datasets.

    Science.gov (United States)

    Mao, Hongliang; Wang, Hao

    2017-03-01

    Short Interspersed Nuclear Elements (SINEs) are transposable elements (TEs) that amplify through a copy-and-paste mode via RNA intermediates. The computational identification of new SINEs are challenging because of their weak structural signals and rapid diversification in sequences. Here we report SINE_Scan, a highly efficient program to predict SINE elements in genomic DNA sequences. SINE_Scan integrates hallmark of SINE transposition, copy number and structural signals to identify a SINE element. SINE_Scan outperforms the previously published de novo SINE discovery program. It shows high sensitivity and specificity in 19 plant and animal genome assemblies, of which sizes vary from 120 Mb to 3.5 Gb. It identifies numerous new families and substantially increases the estimation of the abundance of SINEs in these genomes. The code of SINE_Scan is freely available at http://github.com/maohlzj/SINE_Scan , implemented in PERL and supported on Linux. wangh8@fudan.edu.cn. Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

  19. Pump-flow-probe x-ray absorption spectroscopy as a tool for studying aintermediate states of photocatalytic systems

    DEFF Research Database (Denmark)

    Smolentsev, Grigory; Guda, Alexander; Zhang, Xiaoyi

    2013-01-01

    -millimolar concentrations. A continuous wave laser is used for the photoexcitation, with the distance between laser and X-ray beams and velocity of liquid flow determining the time delay, while the focusing of both beams and the flow speed profile define the time resolution. This method is compared with the alternative...... measurement technique that utilizes a 1 kHz repetition rate laser and multiple X-ray probe pulses. Such an experiment was performed at beamline 11ID-D of the Advanced Photon Source. Advantages, limitations, and potential for improvement of the pump-flow-probe setup are discussed by analyzing the photon...... statistics. Both methods with Co K-edge probing were applied to the investigation of a cobaloxime-based photocatalytic reaction. The interplay between optimizing for efficient photoexcitation and time resolution as well and the effect of sample degradation for these two setups are discussed. © 2013 American...

  20. Reliability and validity of a self-administered tool for online neuropsychological testing : The Amsterdam Cognition Scan

    NARCIS (Netherlands)

    Feenstra, H.E.M.; Murre, J.M.J.; Vermeulen, I. E.; Kieffer, J.M.; Schagen, S.B.

    2018-01-01

    Introduction : To facilitate large-scale assessment of a variety of cognitive abilities in clinical studies, we developed a self-administered online neuropsychological test battery: the Amsterdam Cognition Scan (ACS). The current studies evaluate in a group of adult cancer patients: test–retest

  1. Reliability and validity of a self-administered tool for online neuropsychological testing : The Amsterdam Cognition Scan

    NARCIS (Netherlands)

    Feenstra, Heleen E.M.; Murre, Jaap M.J.; Vermeulen, Ivar E.; Kieffer, Jacobien M.; Schagen, Sanne B.

    2018-01-01

    Introduction: To facilitate large-scale assessment of a variety of cognitive abilities in clinical studies, we developed a self-administered online neuropsychological test battery: the Amsterdam Cognition Scan (ACS). The current studies evaluate in a group of adult cancer patients: test–retest

  2. Scanning drop sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jian; Xiang, Chengxiang; Gregoire, John

    2017-05-09

    Electrochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

  3. Scanning drop sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Jian; Xiang, Chengxiang; Gregoire, John M.; Shinde, Aniketa A.; Guevarra, Dan W.; Jones, Ryan J.; Marcin, Martin R.; Mitrovic, Slobodan

    2017-05-09

    Electrochemical or electrochemical and photochemical experiments are performed on a collection of samples by suspending a drop of electrolyte solution between an electrochemical experiment probe and one of the samples that serves as a test sample. During the electrochemical experiment, the electrolyte solution is added to the drop and an output solution is removed from the drop. The probe and collection of samples can be moved relative to one another so the probe can be scanned across the samples.

  4. Ultrafast supercontinuum fiber-laser based pump-probe scanning magneto-optical Kerr effect microscope for the investigation of electron spin dynamics in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution.

    Science.gov (United States)

    Henn, T; Kiessling, T; Ossau, W; Molenkamp, L W; Biermann, K; Santos, P V

    2013-12-01

    We describe a two-color pump-probe scanning magneto-optical Kerr effect microscope which we have developed to investigate electron spin phenomena in semiconductors at cryogenic temperatures with picosecond time and micrometer spatial resolution. The key innovation of our microscope is the usage of an ultrafast "white light" supercontinuum fiber-laser source which provides access to the whole visible and near-infrared spectral range. Our Kerr microscope allows for the independent selection of the excitation and detection energy while avoiding the necessity to synchronize the pulse trains of two separate picosecond laser systems. The ability to independently tune the pump and probe wavelength enables the investigation of the influence of excitation energy on the optically induced electron spin dynamics in semiconductors. We demonstrate picosecond real-space imaging of the diffusive expansion of optically excited electron spin packets in a (110) GaAs quantum well sample to illustrate the capabilities of the instrument.

  5. Scan-Less Line Field Optical Coherence Tomography, with Automatic Image Segmentation, as a Measurement Tool for Automotive Coatings

    Directory of Open Access Journals (Sweden)

    Samuel Lawman

    2017-04-01

    Full Text Available The measurement of the thicknesses of layers is important for the quality assurance of industrial coating systems. Current measurement techniques only provide a limited amount of information. Here, we show that spectral domain Line Field (LF Optical Coherence Tomography (OCT is able to return to the user a cross sectional B-Scan image in a single shot with no mechanical moving parts. To reliably extract layer thicknesses from such images of automotive paint systems, we present an automatic graph search image segmentation algorithm. To show that the algorithm works independently of the OCT device, the measurements are repeated with a separate time domain Full Field (FF OCT system. This gives matching mean thickness values within the standard deviations of the measured thicknesses across each B-Scan image. The combination of an LF-OCT with graph search segmentation is potentially a powerful technique for the quality assurance of non-opaque industrial coating layers.

  6. A new tool for an old job: Using fixed cell scanning calorimetry to investigate dilute aqueous solutions

    International Nuclear Information System (INIS)

    Woolley, E.M.

    2007-01-01

    The development of fixed twin cell temperature scanning calorimeters has enabled the more efficient determination of heat capacities of dilute aqueous solutions with a precision comparable to that of the Picker flow heat capacity calorimeters developed nearly 40 years ago. Experiments require less than 0.5 cm 3 of solution, and results can be obtained routinely over the temperature range (278 to 395) K at pressures up to a few bars. Multiple scanning of samples by both increasing and decreasing temperature allows assessment of instrument drift, solute stability, and reproducibility of results. Chemical calibration is essential to take full advantage of the precision and sensitivity of the calorimeters. The calorimetric output is a direct measure of the difference in heat capacity per unit volume of a solution and of a reference liquid, usually water. Thus, densities of the solution and reference liquid are needed to transform the results into heat capacities per unit mass of solution. Examples of solutes that have been investigated include a variety of inorganic and organic compounds that dissolve to give simple ionic or neutral species, or that produce complexes or species that exist in equilibrium distributions that can change as the temperature is scanned. Appropriate selection of the results from experiments on combinations of solutes allows calculation of standard state (zero concentration) thermodynamic quantities for chemical processes and reactions over the ranges of temperature scanned at the solution compositions investigated. Results for a few specific systems are presented and discussed for some representative classes of solutes that have been investigated in our laboratory since 1998

  7. Probe-diverse ptychography

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, I., E-mail: isaac.russellpeterson@rmit.edu.au [ARC Centre of Excellence for Coherent X-ray Science, the University of Melbourne, School of Physics, Victoria 3010 (Australia); Harder, R. [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Robinson, I.K. [Research Complex at Harwell, Didcot, Oxfordshire OX11 0DE (United Kingdom); London Centre for Nanotechnology, University College London, London WC1H 0AH (United Kingdom)

    2016-12-15

    We propose an extension of ptychography where the target sample is scanned separately through several probes with distinct amplitude and phase profiles and a diffraction image is recorded for each probe and each sample translation. The resulting probe-diverse dataset is used to iteratively retrieve high-resolution images of the sample and all probes simultaneously. The method is shown to yield significant improvement in the reconstructed sample image compared to the image obtained using the standard single-probe ptychographic phase-retrieval scheme.

  8. Decision Simulation Technique (DST) as a scanning tool for exploring and explicating sustainability issues in transport decision making

    DEFF Research Database (Denmark)

    Jeppesen, Sara Lise

    2009-01-01

    This paper places focus on explicit consideration of sustainability issues in transport decision making by presenting and using a developed “Decision Simulation Technique” (DST). This technique can be used by an analyst to ‘scan’ a transport planning problem with regard to what in DST terms...... is called a sustainability strategy. This scanning can serve the purpose of informing a group of decision makers before they actually have to deal with, for example, the choice among a number of alternatives that have all been formulated as being relevant. The main focus of the paper is to illustrate how...

  9. Combination of Scanning Probe Microscopy and Coordination Chemistry: Structural and Electronic Study of Bis(methylbenzimidazolyl)ketone and Its Iron Complex

    NARCIS (Netherlands)

    Folkertsma, Emma; Van Der Lit, Joost; Di Cicco, Francesca; Lutz, Martin; Klein Gebbink, Robertus J. M.; Swart, Ingmar; Moret, Marc-etienne

    2017-01-01

    Here, we report the bulk synthesis of [FeII(BMBIK)Cl2] bearing the redox noninnocent bis(methylbenzimidazolyl)ketone (BMBIK) ligand and the synthesis of the similar complex [FeI(BMBIK)]+ on a Au(111) surface using lateral manipulation at the atomic level. Cyclic voltammetry and scanning tunneling

  10. High Pressure Scanning Tunneling Microscopy Studies of AdsorbateStructure and Mobility during Catalytic Reactions: Novel Design of anUltra High Pressure, High Temperature Scanning Tunneling MicroscopeSystem for Probing Catalytic Conversions

    Energy Technology Data Exchange (ETDEWEB)

    Tang, David Chi-Wai [Univ. of California, Berkeley, CA (United States)

    2005-05-16

    The aim of the work presented therein is to take advantage of scanning tunneling microscope’s (STM) capability for operation under a variety of environments under real time and at atomic resolution to monitor adsorbate structures and mobility under high pressures, as well as to design a new generation of STM systems that allow imaging in situ at both higher pressures (35 atm) and temperatures (350 °C).

  11. Probing the onset of structural instabilities as a tool for detection of staling of dairy milk: A permittivity and conductivity study

    Science.gov (United States)

    Madhurima, V.; Harindran, Aswini

    2018-05-01

    Dairy milk is a worldwide drink and a versatile raw material for food industries too. The major issue regarding dairy milk is their contamination by micro-organisms and subsequent spoiling. Pasteurization and sealed packing are used to minimize this contamination. The presence of pathogenic micro-organisms like psychrotrophs, reduces the pH of fresh milk by fermenting the lactose into lactic acid leading to the spoiling of milk. While there are various tests to check the spoilage of milk, there is no unique test to detect the onset of the complex dynamics of spoilage. There have been some studies on the dielectric properties of dairy milk but the primary method of identification of freshness of milk is through the measurement of pH. In this study, broadband dielectric spectroscopy is used as a tool to probe the spoiling of milk and that provides the information about the structural changes of milk during spoilage. The gamma dispersion explains the influence of free water content which is found to be a sensitive tool to probe the onset of milk spoilage process. The observations here are further backed by studies on the particle size and zeta potential.

  12. Probing functional groups at the gas-aerosol interface using heterogeneous titration reactions: a tool for predicting aerosol health effects?

    Science.gov (United States)

    Setyan, Ari; Sauvain, Jean-Jacques; Guillemin, Michel; Riediker, Michael; Demirdjian, Benjamin; Rossi, Michel J

    2010-12-17

    The complex chemical and physical nature of combustion and secondary organic aerosols (SOAs) in general precludes the complete characterization of both bulk and interfacial components. The bulk composition reveals the history of the growth process and therefore the source region, whereas the interface controls--to a large extent--the interaction with gases, biological membranes, and solid supports. We summarize the development of a soft interrogation technique, using heterogeneous chemistry, for the interfacial functional groups of selected probe gases [N(CH(3))(3), NH(2)OH, CF(3)COOH, HCl, O(3), NO(2)] of different reactivity. The technique reveals the identity and density of surface functional groups. Examples include acidic and basic sites, olefinic and polycyclic aromatic hydrocarbon (PAH) sites, and partially and completely oxidized surface sites. We report on the surface composition and oxidation states of laboratory-generated aerosols and of aerosols sampled in several bus depots. In the latter case, the biomarker 8-hydroxy-2'-deoxyguanosine, signaling oxidative stress caused by aerosol exposure, was isolated. The increase in biomarker levels over a working day is correlated with the surface density N(i)(O3) of olefinic and/or PAH sites obtained from O(3) uptakes as well as with the initial uptake coefficient, γ(0), of five probe gases used in the field. This correlation with γ(0) suggests the idea of competing pathways occurring at the interface of the aerosol particles between the generation of reactive oxygen species (ROS) responsible for oxidative stress and cellular antioxidants.

  13. Microstructure influence on corrosion behavior of a Fe–Cr–V–N tool alloy studied by SEM/EDS, scanning Kelvin force microscopy and electrochemical measurement

    International Nuclear Information System (INIS)

    Sababi, Majid; Ejnermark, Sebastian; Andersson, Jörgen; Claesson, Per M.; Pan, Jinshan

    2013-01-01

    Highlights: ► Localized corrosion of a new N-based tool alloy (Fe–Cr–V–N) has been studied. ► One-pass mode of scanning Kelvin force microscopy (KFM) was used in the study. ► The focus was on correlation between microstructure and localized corrosion. - Abstract: Microstructure influence on corrosion behavior of an N-based tool alloy (Fe–Cr–V–N) has been studied. Electron microscopy analysis showed two types of hard phases in the alloy. One-pass mode scanning Kelvin force microscopy (KFM) was used to investigate relative nobility of the hard phases. Volta potential mapping indicates higher nobility for the hard phases than the alloy matrix, and, the V- and N-rich particles exhibit the highest Volta potential. Post-polarization analysis by SEM revealed localized dissolution initiated in matrix regions adjacent to hard phase particles, and the boundary region surrounding the Cr- and Mo-rich particles is more prone to localized corrosion.

  14. DESIGN NOTE: From nanometre to millimetre: a feasibility study of the combination of scanning probe microscopy and combined optical and x-ray interferometry

    Science.gov (United States)

    Yacoot, Andrew; Koenders, Ludger

    2003-09-01

    This feasibility study investigates the potential combination of an x-ray interferometer and optical interferometer as a one-dimensional long range high resolution scanning stage for an atomic force microscope (AFM) in order to overcome the problems of non-linearity associated with conventional AFMs and interferometers. Preliminary results of measurements of the uniformity of the period of a grating used as a transfer standards show variations in period at the nanometre level.

  15. Conductive scanning probe microscopy of the semicontinuous gold film and its SERS enhancement toward two-step photo-induced charge transfer and effect of the supportive layer

    Science.gov (United States)

    Sinthiptharakoon, K.; Sapcharoenkun, C.; Nuntawong, N.; Duong, B.; Wutikhun, T.; Treetong, A.; Meemuk, B.; Kasamechonchung, P.; Klamchuen, A.

    2018-05-01

    The semicontinuous gold film, enabling various electronic applications including development of surface-enhanced Raman scattering (SERS) substrate, is investigated using conductive atomic force microscopy (CAFM) and Kelvin probe force microscopy (KPFM) to reveal and investigate local electronic characteristics potentially associated with SERS generation of the film material. Although the gold film fully covers the underlying silicon surface, CAFM results reveal that local conductivity of the film is not continuous with insulating nanoislands appearing throughout the surface due to incomplete film percolation. Our analysis also suggests the two-step photo-induced charge transfer (CT) play the dominant role in the enhancement of SERS intensity with strong contribution from free electrons of the silicon support. Silicon-to-gold charge transport is illustrated by KPFM results showing that Fermi level of the gold film is slightly inhomogeneous and far below the silicon conduction band. We propose that inhomogeneity of the film workfunction affecting chemical charge transfer between gold and Raman probe molecule is associated with the SERS intensity varying across the surface. These findings provide deeper understanding of charge transfer mechanism for SERS which can help in design and development of the semicontinuous gold film-based SERS substrate and other electronic applications.

  16. Scanning electron microscopy and X-ray energy dispersive spectroscopy - useful tools in the analysis of pharmaceutical products

    Science.gov (United States)

    Sarecka-Hujar, Beata; Balwierz, Radoslaw; Ostrozka-Cieslik, Aneta; Dyja, Renata; Lukowiec, Dariusz; Jankowski, Andrzej

    2017-11-01

    The quality of the drug, its purity and identification of degradation products provide the highest quality of pharmaceutical products. The energy dispersive spectroscopy (EDS) method analyses the percentage of each element form as well as their distribution, and morphological characteristics of the drug form. We analysed the usefulness of EDS method in testing orally disintegrating tablets (ODT) with trimetazidine hydrochloride with high resolution scanning electron microscopy (SEM, SUPRA25 Carl Zeiss company) with spectrophotometer equipped with an X-ray energy dispersion (EDAX Company). The samples of the analysed tablets were imaged after applying conductive layers of gold on their surface. In the EDS analysis the compositions of each sample of the obtained tablets were observed to be virtually identical. The differences in the content of carbon and oxygen came from differences in the composition of particular tablets. The presence of gold in the composition resulted from the sputtering the surface of tablets with gold during the analysis. Knowing the composition of the tablet, SEM-EDS method helps to locate and identify the impurities and degradation products of the compounds, leading to a better understanding of the mechanisms of their formation.

  17. The con focal laser scanning microscope: a powerful tool for the investigation of micro devices and nano structures

    International Nuclear Information System (INIS)

    Montereali, R.M.; Baldacchini, G.; Bonfigli, F.; Vincenti, M.A.; Almaviva, S.

    2008-01-01

    In the last years the Con focal Laser Scanning Microscope (CLSM), a versatile and powerful optical instrument, gained a strong increase of interest in the scientific community, not only for biological applications, but also for the characterization of materials, microstructures and devices. The conditions that favoured its wide diffusion are surely the large availability of laser sources and powerful computer-imaging and data-processing systems at relatively low cost; however, the main reason that contributed to its popularity is the ability to obtain tri dimensional reconstruction of a great variety of biological and non-biological samples with sub micrometric resolution. In this report we show the main properties and characteristics of the Con focal Microscope Nikon Eclipse 80-i C1, which has operated sinc more than two years in the Solid State Laser and Spectroscopy Laboratory of the ENEA Research Center in Frascati. Some of the results obtained in the characterization of luminescent micro and nano structures based on lithium fluoride color centers will be presented [it

  18. UV-visible scanning spectrophotometry and chemometric analysis as tools for carotenoids analysis in cassava genotypes (Manihot esculenta Crantz).

    Science.gov (United States)

    Moresco, Rodolfo; Uarrota, Virgílio G; Pereira, Aline; Tomazzoli, Maíra; Nunes, Eduardo da C; Martins Peruch, Luiz Augusto; Gazzola, Jussara; Costa, Christopher; Rocha, Miguel; Maraschin, Marcelo

    2015-12-01

    In this study, the metabolomics characterization focusing on the carotenoid composition of ten cassava (Manihot esculenta) genotypes cultivated in southern Brazil by UV-visible scanning spectrophotometry and reverse phase-high performance liquid chromatography was performed. Cassava roots rich in β-carotene are an important staple food for populations with risk of vitamin A deficiency. Cassava genotypes with high pro-vitamin A activity have been identified as a strategy to reduce the prevalence of deficiency of this vitamin. The data set was used for the construction of a descriptive model by chemometric analysis. The genotypes of yellow-fleshed roots were clustered by the higher concentrations of cis- β-carotene and lutein. Inversely, cream-fleshed roots genotypes were grouped precisely due to their lower concentrations of these pigments, as samples rich in lycopene (redfleshed) differed among the studied genotypes. The analytical approach (UV-Vis, HPLC, and chemometrics) used showed to be efficient for understanding the chemodiversity of cassava genotypes, allowing to classify them according to important features for human health and nutrition.

  19. Optical afterburner for an x-ray free electron laser as a tool for pump-probe experiments

    Directory of Open Access Journals (Sweden)

    E. L. Saldin

    2010-03-01

    Full Text Available We propose a new scheme for two-color operation of an x-ray self-amplified spontaneous emission free electron laser (SASE FEL. The scheme is based on an intrinsic feature of such a device: chaotic modulations of electron beam energy and energy spread on the scale of FEL coherence length are converted into large density modulations on the same scale with the help of a dispersion section, installed behind the x-ray undulator. Powerful radiation is then generated with the help of a dedicated radiator (like an undulator that selects a narrow spectral line, or one can simply use, for instance, broadband edge radiation. A typical radiation wavelength can be as short as a FEL coherence length, and can be redshifted by increasing the dispersion section strength. In practice it means the wavelength ranges from vacuum ultraviolet to infrared. The long-wavelength radiation pulse is naturally synchronized with the x-ray pulse and can be either directly used in pump-probe experiments or cross correlated with a high-power pulse from a conventional laser system. In this way experimenters overcome jitter problems and can perform pump-probe experiments with femtosecond resolution. Additional possibilities like on-line monitoring of x-ray pulse duration (making “optical replica” of an x-ray pulse are also discussed in the paper. The proposed scheme is very simple, cheap, and robust, and therefore can be easily realized in facilities like FLASH, European XFEL, LCLS, and SCSS.

  20. Solution scanning as a key policy tool: identifying management interventions to help maintain and enhance regulating ecosystem services

    Directory of Open Access Journals (Sweden)

    William J. Sutherland

    2014-06-01

    Full Text Available The major task of policy makers and practitioners when confronted with a resource management problem is to decide on the potential solution(s to adopt from a range of available options. However, this process is unlikely to be successful and cost effective without access to an independently verified and comprehensive available list of options. There is currently burgeoning interest in ecosystem services and quantitative assessments of their importance and value. Recognition of the value of ecosystem services to human well-being represents an increasingly important argument for protecting and restoring the natural environment, alongside the moral and ethical justifications for conservation. As well as understanding the benefits of ecosystem services, it is also important to synthesize the practical interventions that are capable of maintaining and/or enhancing these services. Apart from pest regulation, pollination, and global climate regulation, this type of exercise has attracted relatively little attention. Through a systematic consultation exercise, we identify a candidate list of 296 possible interventions across the main regulating services of air quality regulation, climate regulation, water flow regulation, erosion regulation, water purification and waste treatment, disease regulation, pest regulation, pollination and natural hazard regulation. The range of interventions differs greatly between habitats and services depending upon the ease of manipulation and the level of research intensity. Some interventions have the potential to deliver benefits across a range of regulating services, especially those that reduce soil loss and maintain forest cover. Synthesis and applications: Solution scanning is important for questioning existing knowledge and identifying the range of options available to researchers and practitioners, as well as serving as the necessary basis for assessing cost effectiveness and guiding implementation strategies. We

  1. [Usefulness of (18)FDG PET-CT scan as a diagnostic tool of fever of unknown origin].

    Science.gov (United States)

    García-Gómez, Francisco Javier; Acevedo-Báñez, Irene; Martínez-Castillo, Rubén; García-Gutiérrez, Manuel; Tirado-Hospital, Juan Luis; Borrego-Dorado, Isabel

    2015-07-20

    Classic fever of unknown origin (FUO) is defined as the presence of fever greater than 38.3°C of at least 3 weeks with an uncertain diagnosis. Identification of the etiology is crucial in guiding further diagnostic procedures and subsequent patient management. The aim of this study was to evaluate the role of fluorine-18 fluorodeoxyglucose ((18)F-FDG) positron emission tomography combined with computed tomography (PET/CT) in the diagnostic orientation of FUO. An observational retrospective study was performed, including 30 consecutive patients who had been studied between March 2010 and September 2013. Twenty-six out of 30 patients (86.67%) had a definitive diagnosis after pathologic confirmation in 15 cases, microbiological findings in one patient and clinical and radiological follow-up in 10 patients (mean: 16.38 months). Among the positive scans, malignancy (n=10), inflammatory (n=8), infectious (n=4) and miscellaneous causes (n=1) were identified. (18)F-FDG PET/CT had a diagnostic accuracy of 90.00%, sensitivity of 88.46% (95% confidence interval [95% CI] 76-101), specificity of 100.00% (95% CI 100-100), positive predictive values of 100.00% (95% CI100-100) and negative predictive value of 57.14% (95% CI 20-91). (18)F-FDG PET/CT provided useful for the etiologic diagnosis of FUO, with high sensitivity and specificity. (18)F-FDG PET/CT has an incremental morphological and functional value, especially indicating the best biopsy site. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  2. Superconductivity and electronic structure in single-layer FeSe on SrTiO{sub 3} probed by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jandke, Jasmin; Dressner, Jonas; Wulfhekel, Wulf [Physikalisches Institut, Karlsruhe Institute of Technology (Germany); Yang, Fang; Gao, Chunlei [Fudan Universitaet, Shanghai (China)

    2016-07-01

    We use high-resolution scanning tunneling spectroscopy (STS) to study single-layer FeSe on Nb-doped SrTiO{sub 3} (001). Features of bosonic excitations were observed in the measured quasiparticle density of states. Furthermore, using STS, quasiparticle interference (QPI) imaging was performed in order to map the multiband electronic structure of FeSe. Compared to previous measurements, an additional feature is visible in our measured QPI maps on a single-layer FeSe/SrTiO{sub 3}. The origin of this feature will be discussed.

  3. Probing the limits of Si:P δ-doped devices patterned by a scanning tunneling microscope in a field-emission mode

    Energy Technology Data Exchange (ETDEWEB)

    Rudolph, M.; Carr, S. M.; Ten Eyck, G.; Dominguez, J.; Carroll, M. S.; Bussmann, E. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Subramania, G. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Lilly, M. P. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Pluym, T.

    2014-10-20

    Recently, a single atom transistor was deterministically fabricated using phosphorus in Si by H-desorption lithography with a scanning tunneling microscope (STM). This milestone in precision, achieved by operating the STM in the conventional tunneling mode, typically utilizes slow (∼10{sup 2} nm{sup 2}/s) patterning speeds. By contrast, using the STM in a high-voltage (>10 V) field-emission mode, patterning speeds can be increased by orders of magnitude to ≳10{sup 4} nm{sup 2}/s. We show that the rapid patterning negligibly affects the functionality of relatively large micron-sized features, which act as contacting pads for these devices. For nanoscale structures, we show that the resulting electrical transport is consistent with the donor incorporation chemistry constraining the electrical dimensions to a scale of 10 nm even though the pattering spot size is 40 nm.

  4. Probing the thermal decomposition behaviors of ultrathin HfO2 films by an in situ high temperature scanning tunneling microscope.

    Science.gov (United States)

    Xue, Kun; Wang, Lei; An, Jin; Xu, Jianbin

    2011-05-13

    The thermal decomposition of ultrathin HfO(2) films (∼0.6-1.2 nm) on Si by ultrahigh vacuum annealing (25-800 °C) is investigated in situ in real time by scanning tunneling microscopy. Two distinct thickness-dependent decomposition behaviors are observed. When the HfO(2) thickness is ∼ 0.6 nm, no discernible morphological changes are found below ∼ 700 °C. Then an abrupt reaction occurs at 750 °C with crystalline hafnium silicide nanostructures formed instantaneously. However, when the thickness is about 1.2 nm, the decomposition proceeds gradually with the creation and growth of two-dimensional voids at 800 °C. The observed thickness-dependent behavior is closely related to the SiO desorption, which is believed to be the rate-limiting step of the decomposition process.

  5. Scanning tunneling spectroscopy to probe odd-triplet contributions to the long-ranged proximity effect in Al-EuS

    Energy Technology Data Exchange (ETDEWEB)

    Diesch, Simon; Machon, Peter; Belzig, Wolfgang; Scheer, Elke [Universitaet Konstanz, Konstanz (Germany); Suergers, Christoph; Beckmann, Detlef [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2016-07-01

    Experiments on superconductor-ferromagnet-systems have shown Cooper pairs tunneling through ferromagnetic layers, indicating Cooper pairs of equal spin, thus corresponding to a long-range triplet proximity effect. Most experimental evidence for triplet superconductivity comes from observations of the thickness dependence of the Josephson current through a ferromagnetic barrier, but there is an increasing interest in obtaining direct spectroscopic evidence. This project aims to analyze the DOS of thin films of the ferromagnetic insulator europium sulfide on superconducting aluminum or vice versa, using a scanning tunneling microscope in spectroscopy mode at 280 mK and in varying magnetic fields. We observe significant broadening of the superconducting energy gap and a variety of sub-gap structures induced by the presence of the ferromagnet and interpret our findings based on the diffusive theory.

  6. Scanning Kelvin probe force microscopy as a means of predicting the electrochemical characteristics of the surface of a modified AA4xxx/AA3xxx (Al alloys) brazing sheet

    International Nuclear Information System (INIS)

    Afshar, F. Norouzi; Wit, J.H.W. de; Terryn, H.; Mol, J.M.C.

    2013-01-01

    Highlights: ► Macro- and micro-electrochemical surface properties of an aluminium brazing sheet were investigated. ► Electrochemical surface properties before and after brazing were studied and compared. ► Scanning Kelvin probe force microscopy and potentiodynamic polarization measurements were performed. ► The electrochemical responses were correlated to the pre- and post-brazing treatment microstructure. -- Abstract: Macro- and micro-electrochemical properties of clad and core surfaces of a modified AA4xxx/AA3xxx brazing sheet material, before and after brazing, have been evaluated and compared. By scanning Kelvin probe force microscopy (SKPFM), the Volta potential distribution over the brazed and non-brazed clad surfaces was measured. The changes in the Volta potential maps were correlated to the macro-electrochemical responses of the surfaces and the microstructural features that evolve as a result of brazing. By performing potentiodynamic polarization experiments and microscopic analysis of the corroded surfaces and cross sections, the suitability of SKPFM analysis for corrosion performance prediction of the aluminium brazing sheet material in a sea water acidified accelerated test (SWAAT) environment was confirmed. Considering the purity of Si phase in the structures of both brazed and non-brazed material, it is suggested that Si can be applied as a reliable local reference in both structures to compare the changes in Volta potential differences as the result of different heat treatments of aluminium brazing sheet. Increasing the copper content of the re-solidified clad material as a result of brazing treatment was found to increase the Volta potential of the matrix which in turn reduces the cathodic protection power of the re-solidified clad material towards the core material

  7. 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT scans as diagnostic tools in focal congenital hyperinsulinism

    DEFF Research Database (Denmark)

    Christiansen, Charlotte Dahl; Petersen, Henrik; Nielsen, Anne Lerberg

    2018-01-01

    (68Ga-DOTANOC) PET/CT as diagnostic tools in focal CHI. Methods: PET/CT scans of children with CHI admitted to Odense University Hospital between August 2005 and June 2016 were retrospectively evaluated visually and by their maximal standardized uptake values (SUVmax) by two independent examiners......, blinded for clinical, surgical and pathological data. Pancreatic histology was used as the gold standard. For patients without surgery, the genetic profile served as the gold standard. Results: Fifty-five CHI patients were examined by PET/CT (18F-DOPA n = 53, 68Ga-DOTANOC n = 18). Surgery was performed...... in 34 patients, no surgery in 21 patients. Fifty-one patients had a classifiable outcome, either by histology (n = 33, 22 focal lesions, 11 non-focal) or by genetics (n = 18, all non-focal). The predictive performance of 18F-DOPA PET/CT to identify focal CHI was identical by visual- and cut...

  8. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff Mathiasen, Anne-Gitte

    2013-01-01

    Mobile probing is a method, developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time and space......). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings point...... to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face). The development...

  9. Mobile Probing and Probes

    DEFF Research Database (Denmark)

    Duvaa, Uffe; Ørngreen, Rikke; Weinkouff, Anne-Gitte

    2012-01-01

    Mobile probing is a method, which has been developed for learning about digital work situations, as an approach to discover new grounds. The method can be used when there is a need to know more about users and their work with certain tasks, but where users at the same time are distributed (in time...... and space). Mobile probing was inspired by the cultural probe method, and was influenced by qualitative interview and inquiry approaches. The method has been used in two subsequent projects, involving school children (young adults at 15-17 years old) and employees (adults) in a consultancy company. Findings...... point to mobile probing being a flexible method for uncovering the unknowns, as a way of getting rich data to the analysis and design phases. On the other hand it is difficult to engage users to give in depth explanations, which seem easier in synchronous dialogs (whether online or face2face...

  10. High Pressure Scanning Tunneling Microscopy Studies of Adsorbate Structure and Mobility during Catalytic Reactions. Novel Design of an Ultra High Pressure, High Temperature Scanning Tunneling Microscope System for Probing Catalytic Conversions

    International Nuclear Information System (INIS)

    Tang, David Chi-Wai

    2005-01-01

    The aim of the work presented therein is to take advantage of scanning tunneling microscope's (STM) capability for operation under a variety of environments under real time and at atomic resolution to monitor adsorbate structures and mobility under high pressures, as well as to design a new generation of STM systems that allow imaging in situ at both higher pressures (35 atm) and temperatures (350 C). The design of a high pressure, high temperature scanning tunneling microscope system, that is capable of monitoring reactions in situ at conditions from UHV and ambient temperature up to 1 atm and 250 C, is briefly presented along with vibrational and thermal analysis, as this system serves as a template to improve upon during the design of the new ultra high pressure, high temperature STM. Using this existing high pressure scanning tunneling microscope we monitored the co-adsorption of hydrogen, ethylene and carbon dioxide on platinum (111) and rhodium (111) crystal faces in the mTorr pressure range at 300 K in equilibrium with the gas phase. During the catalytic hydrogenation of ethylene to ethane in the absence of CO the metal surfaces are covered by an adsorbate layer that is very mobile on the time scale of STM imaging. We found that the addition of CO poisons the hydrogenation reaction and induces ordered structures on the single crystal surfaces. Several ordered structures were observed upon CO addition to the surfaces pre-covered with hydrogen and ethylene: a rotated (√19 x √19)R23.4 o on Pt(111), and domains of c(4 x 2)-CO+C 2 H 3 , previously unobserved (4 x 2)-CO+3C 2 H 3 , and (2 x 2)-3CO on Rh(111). A mechanism for CO poisoning of ethylene hydrogenation on the metal single crystals was proposed, in which CO blocks surface metal sites and reduces adsorbate mobility to limit adsorption and reaction rate of ethylene and hydrogen. In order to observe heterogeneous catalytic reactions that occur well above ambient pressure and temperature that more closely

  11. Evolution of the Copper Surface in the Course of Oxidation by CCl4-L (L=THF, Dmf, Dmso): Scanning Probe Microscope Study

    Science.gov (United States)

    Panteleev, S. V.; Maslennikov, S. V.; Ignatov, S. K.; Spirina, I. V.; Kruglova, M. V.; Gribkov, B. A.; Vdovichev, S. N.

    2013-04-01

    The evolution of compact surface of the 100 nm copper film deposited on the glass-ceramics doped with vanadium coating in the course of the oxidation by the CCl4-L (L = dimethylformamide (DMF), tetrahydrofuran (THF), dimethylsulfoxide (DMSO), CCl4 concentration ≈ 1 mol/L) was studied by atomic force microscopy (AFM) in contact mode. The dynamics of active centers formation and destruction was investigated in the course of the oxidation process. The metallic sample dissolution rate was estimated as a function of the coordinating solvent nature. The development of the metal surface oxidation was established to lead to a significant increase of surface roughness. This phenomenon can be explained by the fact that different parts of the surface react at different rates. Further course of the reaction leads to a significant decrease of the surface roughness of copper films. The amount of the metal reacted has an almost linear dependence on the reaction time. AFM scans indicate that there is the same mechanism of the reaction between copper and carbon tetrachloride for all solvents.

  12. Metabolic and improved organ scan studies. II. Nitrogen-13 labeled compounds used as in-vivo probes for enzyme therapy and as tumor localizing and organ imaging agents

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    A number of 13 N-labeled compounds have been enzymatically synthesized and are being evaluated as tumor and/or organ localizing agents. 13 N-Ammonia, produced after cyclotron generation of 13 N-nitrate and subsequent reduction was used to enzymatically aminate the appropriate substrate to yield 13 N-L-glutamic acid, L-glutamine, L-asparagine, L-valine, L-leucine and L-alanine. The use of 13 N-asparagine as a myocardial scanning agent and as a tumor localizing agent in asparaginase-sensitive tumors is discussed. Two imaging devices were used to study the effectiveness of the compounds as localizing agents. For static whole body distribution studies, a dual-detector high energy gamma ray (HEG) rectilinear scanner, equipped with constant response collimators was employed. The uniformity of response of this system permits quantitative determination of the amount of 13 N activity present in the organ or tumor of interest. The total organ kinetic imaging monitor (TOKIM) gamma camera system was used for dynamic studies covering smaller areas of the subject's body

  13. Optical nonlinearities of colloidal InP@ZnS core-shell quantum dots probed by Z-scan and two-photon excited emission

    International Nuclear Information System (INIS)

    Wawrzynczyk, Dominika; Szeremeta, Janusz; Samoc, Marek; Nyk, Marcin

    2015-01-01

    Spectrally resolved nonlinear optical properties of colloidal InP@ZnS core-shell quantum dots of various sizes were investigated with the Z-scan technique and two-photon fluorescence excitation method using a femtosecond laser system tunable in the range from 750 nm to 1600 nm. In principle, both techniques should provide comparable results and can be interchangeably used for determination of the nonlinear optical absorption parameters, finding maximal values of the cross sections and optimizing them. We have observed slight differences between the two-photon absorption cross sections measured by the two techniques and attributed them to the presence of non-radiative paths of absorption or relaxation. The most significant value of two-photon absorption cross section σ 2 for 4.3 nm size InP@ZnS quantum dot was equal to 2200 GM, while the two-photon excitation action cross section σ 2 Φ was found to be 682 GM at 880 nm. The properties of these cadmium-free colloidal quantum dots can be potentially useful for nonlinear bioimaging

  14. Hydration Effects on Skin Microstructure as Probed by High-Resolution Cryo-Scanning Electron Microscopy and Mechanistic Implications to Enhanced Transcutaneous Delivery of Biomacromolecules

    Science.gov (United States)

    Tan, Grace; Xu, Peng; Lawson, Louise B.; He, Jibao; Freytag, Lucia C.; Clements, John D.; John, Vijay T.

    2010-01-01

    Although hydration is long known to improve the permeability of skin, penetration of macromolecules such as proteins is limited and the understanding of enhanced transport is based on empirical observations. This study uses high-resolution cryo-scanning electron microscopy to visualize microstructural changes in the stratum corneum (SC) and enable a mechanistic interpretation of biomacromolecule penetration through highly hydrated porcine skin. Swollen corneocytes, separation of lipid bilayers in the SC intercellular space to form cisternae, and networks of spherical particulates are observed in porcine skin tissue hydrated for a period of 4–10 h. This is explained through compaction of skin lipids when hydrated, a reversal in the conformational transition from unilamellar liposomes in lamellar granules to lamellae between keratinocytes when the SC skin barrier is initially established. Confocal microscopy studies show distinct enhancement in penetration of fluorescein isothiocyanate-bovine serum albumin (FITC-BSA) through skin hydrated for 4–10 h, and limited penetration of FITC-BSA once skin is restored to its natively hydrated structure when exposed to the environment for 2–3 h. These results demonstrate the effectiveness of a 4–10 h hydration period to enhance transcutaneous penetration of large biomacromolecules without permanently damaging the skin. PMID:19582754

  15. Fluorescence imaging of reactive oxygen species by confocal laser scanning microscopy for track analysis of synchrotron X-ray photoelectric nanoradiator dose: X-ray pump-optical probe.

    Science.gov (United States)

    Jeon, Jae Kun; Han, Sung Mi; Kim, Jong Ki

    2016-09-01

    Bursts of emissions of low-energy electrons, including interatomic Coulomb decay electrons and Auger electrons (0-1000 eV), as well as X-ray fluorescence produced by irradiation of large-Z element nanoparticles by either X-ray photons or high-energy ion beams, is referred to as the nanoradiator effect. In therapeutic applications, this effect can damage pathological tissues that selectively take up the nanoparticles. Herein, a new nanoradiator dosimetry method is presented that uses probes for reactive oxygen species (ROS) incorporated into three-dimensional gels, on which macrophages containing iron oxide nanoparticles (IONs) are attached. This method, together with site-specific irradiation of the intracellular nanoparticles from a microbeam of polychromatic synchrotron X-rays (5-14 keV), measures the range and distribution of OH radicals produced by X-ray emission or superoxide anions ({\\rm{O}}_2^-) produced by low-energy electrons. The measurements are based on confocal laser scanning of the fluorescence of the hydroxyl radical probe 2-[6-(4'-amino)phenoxy-3H-xanthen-3-on-9-yl] benzoic acid (APF) or the superoxide probe hydroethidine-dihydroethidium (DHE) that was oxidized by each ROS, enabling tracking of the radiation dose emitted by the nanoradiator. In the range 70 µm below the irradiated cell, ^\\bullet{\\rm{OH}} radicals derived mostly from either incident X-ray or X-ray fluorescence of ION nanoradiators are distributed along the line of depth direction in ROS gel. In contrast, {\\rm{O}}_2^- derived from secondary electron or low-energy electron emission by ION nanoradiators are scattered over the ROS gel. ROS fluorescence due to the ION nanoradiators was observed continuously to a depth of 1.5 mm for both oxidized APF and oxidized DHE with relatively large intensity compared with the fluorescence caused by the ROS produced solely by incident primary X-rays, which was limited to a depth of 600 µm, suggesting dose enhancement as well as more

  16. The electrochemical interface of Ag(111) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid—A combined in-situ scanning probe microscopy and impedance study

    International Nuclear Information System (INIS)

    Li, Mian-Gang; Chen, Li; Zhong, Yun-Xin; Chen, Zhao-Bin; Yan, Jia-Wei; Mao, Bing-Wei

    2016-01-01

    The electrochemical interface between Ag(111) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI) has been investigated by in-situ scanning probe microscopy (SPM) and electrochemical impedance spectroscopy (EIS). In-situ scanning tunneling microscopy (STM) characterization has revealed that there is neither surface reconstruction nor strong adsorption of EMITFSI on Ag(111) surface so that EIS investigation can be fulfilled under well-defined surface condition and in the absence of pseudo capacitive process. In-situ atom force microscopy (AFM) force curve measurements further disclose that there exists five layered structures near and normal to the surface, among them three layered structures being charged and forming the electric double layer (EDL) of the interface. An electric equivalent circuit is proposed, which comprises two serial parallel branches involving the innermost layered structure and the next two layered structures in the EDL, respectively. The inner layer circuit is given by a constant phase element (CPE) in parallel to a resistor, while the outer layer circuit is given by a capacity in parallel with a resistor-Warburg element branch. Slow response is observed for the inner layer, which is attributed to the hindrance of reorientation and/or redistribution of ions in the more ordered and robust inner layer region. The inner layer capacitance and outer layer capacitance have opposing potential dependence, and the resultant double layer capacitance shows weak potential dependence.

  17. Kelvin probe force microscopy from single charge detection to device characterization

    CERN Document Server

    Glatzel, Thilo

    2018-01-01

    This book provides a comprehensive introduction to the methods and variety of Kelvin probe force microscopy, including technical details. It also offers an overview of the recent developments and numerous applications, ranging from semiconductor materials, nanostructures and devices to sub-molecular and atomic scale electrostatics. In the last 25 years, Kelvin probe force microscopy has developed from a specialized technique applied by a few scanning probe microscopy experts into a tool used by numerous research and development groups around the globe. This sequel to the editors’ previous volume “Kelvin Probe Force Microscopy: Measuring and Compensating Electrostatic Forces,” presents new and complementary topics. It is intended for a broad readership, from undergraduate students to lab technicians and scanning probe microscopy experts who are new to the field.

  18. EDITORIAL: Probing the nanoworld Probing the nanoworld

    Science.gov (United States)

    Miles, Mervyn

    2009-10-01

    In nanotechnology, it is the unique properties arising from nanometre-scale structures that lead not only to their technological importance but also to a better understanding of the underlying science. Over the last twenty years, material properties at the nanoscale have been dominated by the properties of carbon in the form of the C60 molecule, single- and multi-wall carbon nanotubes, nanodiamonds, and recently graphene. During this period, research published in the journal Nanotechnology has revealed the amazing mechanical properties of such materials as well as their remarkable electronic properties with the promise of new devices. Furthermore, nanoparticles, nanotubes, nanorods, and nanowires from metals and dielectrics have been characterized for their electronic, mechanical, optical, chemical and catalytic properties. Scanning probe microscopy (SPM) has become the main characterization technique and atomic force microscopy (AFM) the most frequently used SPM. Over the past twenty years, SPM techniques that were previously experimental in nature have become routine. At the same time, investigations using AFM continue to yield impressive results that demonstrate the great potential of this powerful imaging tool, particularly in close to physiological conditions. In this special issue a collaboration of researchers in Europe report the use of AFM to provide high-resolution topographical images of individual carbon nanotubes immobilized on various biological membranes, including a nuclear membrane for the first time (Lamprecht C et al 2009 Nanotechnology 20 434001). Other SPM developments such as high-speed AFM appear to be making a transition from specialist laboratories to the mainstream, and perhaps the same may be said for non-contact AFM. Looking to the future, characterisation techniques involving SPM and spectroscopy, such as tip-enhanced Raman spectroscopy, could emerge as everyday methods. In all these advanced techniques, routinely available probes will

  19. A new glucocerebrosidase-deficient neuronal cell model provides a tool to probe pathophysiology and therapeutics for Gaucher disease.

    Science.gov (United States)

    Westbroek, Wendy; Nguyen, Matthew; Siebert, Marina; Lindstrom, Taylor; Burnett, Robert A; Aflaki, Elma; Jung, Olive; Tamargo, Rafael; Rodriguez-Gil, Jorge L; Acosta, Walter; Hendrix, An; Behre, Bahafta; Tayebi, Nahid; Fujiwara, Hideji; Sidhu, Rohini; Renvoise, Benoit; Ginns, Edward I; Dutra, Amalia; Pak, Evgenia; Cramer, Carole; Ory, Daniel S; Pavan, William J; Sidransky, Ellen

    2016-07-01

    Glucocerebrosidase is a lysosomal hydrolase involved in the breakdown of glucosylceramide. Gaucher disease, a recessive lysosomal storage disorder, is caused by mutations in the gene GBA1 Dysfunctional glucocerebrosidase leads to accumulation of glucosylceramide and glycosylsphingosine in various cell types and organs. Mutations in GBA1 are also a common genetic risk factor for Parkinson disease and related synucleinopathies. In recent years, research on the pathophysiology of Gaucher disease, the molecular link between Gaucher and Parkinson disease, and novel therapeutics, have accelerated the need for relevant cell models with GBA1 mutations. Although induced pluripotent stem cells, primary rodent neurons, and transfected neuroblastoma cell lines have been used to study the effect of glucocerebrosidase deficiency on neuronal function, these models have limitations because of challenges in culturing and propagating the cells, low yield, and the introduction of exogenous mutant GBA1 To address some of these difficulties, we established a high yield, easy-to-culture mouse neuronal cell model with nearly complete glucocerebrosidase deficiency representative of Gaucher disease. We successfully immortalized cortical neurons from embryonic null allele gba(-/-) mice and the control littermate (gba(+/+)) by infecting differentiated primary cortical neurons in culture with an EF1α-SV40T lentivirus. Immortalized gba(-/-) neurons lack glucocerebrosidase protein and enzyme activity, and exhibit a dramatic increase in glucosylceramide and glucosylsphingosine accumulation, enlarged lysosomes, and an impaired ATP-dependent calcium-influx response; these phenotypical characteristics were absent in gba(+/+) neurons. This null allele gba(-/-) mouse neuronal model provides a much-needed tool to study the pathophysiology of Gaucher disease and to evaluate new therapies. © 2016. Published by The Company of Biologists Ltd.

  20. A new glucocerebrosidase-deficient neuronal cell model provides a tool to probe pathophysiology and therapeutics for Gaucher disease

    Directory of Open Access Journals (Sweden)

    Wendy Westbroek

    2016-07-01

    Full Text Available Glucocerebrosidase is a lysosomal hydrolase involved in the breakdown of glucosylceramide. Gaucher disease, a recessive lysosomal storage disorder, is caused by mutations in the gene GBA1. Dysfunctional glucocerebrosidase leads to accumulation of glucosylceramide and glycosylsphingosine in various cell types and organs. Mutations in GBA1 are also a common genetic risk factor for Parkinson disease and related synucleinopathies. In recent years, research on the pathophysiology of Gaucher disease, the molecular link between Gaucher and Parkinson disease, and novel therapeutics, have accelerated the need for relevant cell models with GBA1 mutations. Although induced pluripotent stem cells, primary rodent neurons, and transfected neuroblastoma cell lines have been used to study the effect of glucocerebrosidase deficiency on neuronal function, these models have limitations because of challenges in culturing and propagating the cells, low yield, and the introduction of exogenous mutant GBA1. To address some of these difficulties, we established a high yield, easy-to-culture mouse neuronal cell model with nearly complete glucocerebrosidase deficiency representative of Gaucher disease. We successfully immortalized cortical neurons from embryonic null allele gba−/− mice and the control littermate (gba+/+ by infecting differentiated primary cortical neurons in culture with an EF1α-SV40T lentivirus. Immortalized gba−/− neurons lack glucocerebrosidase protein and enzyme activity, and exhibit a dramatic increase in glucosylceramide and glucosylsphingosine accumulation, enlarged lysosomes, and an impaired ATP-dependent calcium-influx response; these phenotypical characteristics were absent in gba+/+ neurons. This null allele gba−/− mouse neuronal model provides a much-needed tool to study the pathophysiology of Gaucher disease and to evaluate new therapies.

  1. Multiplex fluorescence melting curve analysis for mutation detection with dual-labeled, self-quenched probes.

    Directory of Open Access Journals (Sweden)

    Qiuying Huang

    2011-04-01

    Full Text Available Probe-based fluorescence melting curve analysis (FMCA is a powerful tool for mutation detection based on melting temperature generated by thermal denaturation of the probe-target hybrid. Nevertheless, the color multiplexing, probe design, and cross-platform compatibility remain to be limited by using existing probe chemistries. We hereby explored two dual-labeled, self-quenched probes, TaqMan and shared-stem molecular beacons, in their ability to conduct FMCA. Both probes could be directly used for FMCA and readily integrated with closed-tube amplicon hybridization under asymmetric PCR conditions. Improved flexibility of FMCA by using these probes was illustrated in three representative applications of FMCA: mutation scanning, mutation identification and mutation genotyping, all of which achieved improved color-multiplexing with easy probe design and versatile probe combination and all were validated with a large number of real clinical samples. The universal cross-platform compatibility of these probes-based FMCA was also demonstrated by a 4-color mutation genotyping assay performed on five different real-time PCR instruments. The dual-labeled, self-quenched probes offered unprecedented combined advantage of enhanced multiplexing, improved flexibility in probe design, and expanded cross-platform compatibility, which would substantially improve FMCA in mutation detection of various applications.

  2. Nuclear Scans

    Science.gov (United States)

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  3. Scanning Electron Microscopy-Energy-Dispersive X-Ray (SEM/EDX): A Rapid Diagnostic Tool to Aid the Identification of Burnt Bone and Contested Cremains.

    Science.gov (United States)

    Ellingham, Sarah T D; Thompson, Tim J U; Islam, Meez

    2018-03-01

    This study investigates the use of Scanning electron microscopy-energy-dispersive X-ray (SEM-EDX) as a diagnostic tool for the determination of the osseous origin of samples subjected to different temperatures. Sheep (Ovis aries) ribs of two experimental groups (fleshed and defleshed) were burned at temperatures of between 100°C and 1100°C in 100°C increments and subsequently analyzed with the SEM-EDX to determine the atomic percentage of present elements. Three-factor ANOVA analysis showed that neither the exposure temperature, nor whether the burning occurred with or without soft tissue present had any significant influence on the bone's overall elemental makeup (p > 0.05). The Ca/P ratio remained in the osseous typical range of between 1.6 and 2.58 in all analyzed samples. This demonstrates that even faced with high temperatures, the overall gross elemental content and atomic percentage of elements in bone remain stable, creating a unique "fingerprint" for osseous material, even after exposure to extreme conditions. © 2017 American Academy of Forensic Sciences.

  4. Innovative SPM Probes for Energy-Storage Science: MWCNT-Nanopipettes to Nanobattery Probes

    Science.gov (United States)

    Larson, Jonathan; Talin, Alec; Pearse, Alexander; Kozen, Alexander; Reutt-Robey, Janice

    As energy-storage materials and designs continue to advance, new tools are needed to direct and explore ion insertion/de-insertion at well-defined battery materials interfaces. Scanned probe tips, assembled from actual energy-storage materials, permit SPM measures of local cathode-anode (tip-sample) interactions, including ion transfer. We present examples of ``cathode'' MWCNT-terminated STM probe tips interacting with Li(s)/Si(111) anode substrates. The MWCNT tip functions as both SPM probe and Li-nanopipette,[1] for controlled transport and manipulation of Li. Local field conditions for lithium ionization and transfer are determined and compared to electrostatic models. Additional lithium metallic and oxide tips have been prepared by thin film deposition on conventional W tips, the latter of which effectively functions as a nanobattery. We demonstrate use of these novel probe materials in the local lithiation of low-index Si anode interfaces, probing local barriers for lithium insertion. Prospects and limitations of these novel SPM probes will be discussed. U.S. Department of Energy Award Number DESC0001160.

  5. SCANNING KELVIN PROBE APPLIED TO LOCALISED ...

    African Journals Online (AJOL)

    2015-01-15

    Jan 15, 2015 ... galvanised steel; with an introduced defect in the coating and various ... susceptibility since the oxide layer covering them may contain flaws or intrinsically offer less protection [5], while the electrochemical characteristics of the ...

  6. Voice coil based scanning probe microscopy

    Czech Academy of Sciences Publication Activity Database

    Klapetek, P.; Valtr, M.; Duchoň, V.; Sobota, Jaroslav

    2012-01-01

    Roč. 7, č. 6 (2012), 332:1-7 ISSN 1931-7573 R&D Projects: GA MPO FR-TI1/241; GA AV ČR KAN311610701; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : SPM * Voice coil * Interferometry Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.524, year: 2012

  7. Scanning Probe Microscope-Based Fluid Dispensing

    NARCIS (Netherlands)

    Ghatkesar, M.K.; Perez Garza, H.H.; Heuck, F.; Staufer, U.

    2014-01-01

    Advances in micro and nano fabrication technologies have enabled fabrication of smaller and more sensitive devices for applications not only in solid-state physics but also in medicine and biology. The demand for devices that can precisely transport material, specifically fluids are continuously

  8. Local crystallography analysis for atomically resolved scanning tunneling microscopy images

    International Nuclear Information System (INIS)

    Lin, Wenzhi; Li, Qing; Belianinov, Alexei; Gai, Zheng; Baddorf, Arthur P; Pan, Minghu; Jesse, Stephen; Kalinin, Sergei V; Sales, Brian C; Sefat, Athena

    2013-01-01

    Scanning probe microscopy has emerged as a powerful and flexible tool for atomically resolved imaging of surface structures. However, due to the amount of information extracted, in many cases the interpretation of such data is limited to being qualitative and semi-quantitative in nature. At the same time, much can be learned from local atom parameters, such as distances and angles, that can be analyzed and interpreted as variations of local chemical bonding, or order parameter fields. Here, we demonstrate an iterative algorithm for indexing and determining atomic positions that allows the analysis of inhomogeneous surfaces. This approach is further illustrated by local crystallographic analysis of several real surfaces, including highly ordered pyrolytic graphite and an Fe-based superconductor FeTe 0.55 Se 0.45 . This study provides a new pathway to extract and quantify local properties for scanning probe microscopy images. (paper)

  9. Renal scan

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003790.htm Renal scan To use the sharing features on this ... anaphylaxis . Alternative Names Renogram; Kidney scan Images Kidney anatomy Kidney - blood and urine flow References Chernecky CC, ...

  10. CT Scan

    Science.gov (United States)

    ... disease, lung nodules and liver masses Monitor the effectiveness of certain treatments, such as cancer treatment Detect ... scan done in a hospital or an outpatient facility. CT scans are painless and, with newer machines, ...

  11. Scanning tunneling microscopy II further applications and related scanning techniques

    CERN Document Server

    Güntherodt, Hans-Joachim

    1995-01-01

    Scanning Tunneling Microscopy II, like its predecessor, presents detailed and comprehensive accounts of the basic principles and broad range of applications of STM and related scanning probe techniques. The applications discussed in this volume come predominantly from the fields of electrochemistry and biology. In contrast to those described in STM I, these studies may be performed in air and in liquids. The extensions of the basic technique to map other interactions are described in chapters on scanning force microscopy, magnetic force microscopy, and scanning near-field optical microscopy, together with a survey of other related techniques. Also described here is the use of a scanning proximal probe for surface modification. Together, the two volumes give a comprehensive account of experimental aspects of STM. They provide essential reading and reference material for all students and researchers involved in this field. In this second edition the text has been updated and new methods are discussed.

  12. Scanning tunneling microscopy II further applications and related scanning techniques

    CERN Document Server

    Güntherodt, Hans-Joachim

    1992-01-01

    Scanning Tunneling Microscopy II, like its predecessor, presents detailed and comprehensive accounts of the basic principles and broad range of applications of STM and related scanning probe techniques. The applications discussed in this volume come predominantly from the fields of electrochemistry and biology. In contrast to those described in Vol. I, these sudies may be performed in air and in liquids. The extensions of the basic technique to map other interactions are described inchapters on scanning force microscopy, magnetic force microscopy, scanning near-field optical microscopy, together with a survey of other related techniques. Also described here is the use of a scanning proximal probe for surface modification. Togehter, the two volumes give a comprehensive account of experimental aspcets of STM. They provide essentialreading and reference material for all students and researchers involvedin this field.

  13. 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT scans as diagnostic tools in focal congenital hyperinsulinism: a blinded evaluation.

    Science.gov (United States)

    Christiansen, Charlotte Dahl; Petersen, Henrik; Nielsen, Anne Lerberg; Detlefsen, Sönke; Brusgaard, Klaus; Rasmussen, Lars; Melikyan, Maria; Ekström, Klas; Globa, Evgenia; Rasmussen, Annett Helleskov; Hovendal, Claus; Christesen, Henrik Thybo

    2018-02-01

    Focal congenital hyperinsulinism (CHI) is curable by surgery, which is why identification of the focal lesion is crucial. We aimed to determine the use of 18F-fluoro-dihydroxyphenylalanine (18F-DOPA) PET/CT vs. 68Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic-acid-1-Nal3-octreotide (68Ga-DOTANOC) PET/CT as diagnostic tools in focal CHI. PET/CT scans of children with CHI admitted to Odense University Hospital between August 2005 and June 2016 were retrospectively evaluated visually and by their maximal standardized uptake values (SUV max ) by two independent examiners, blinded for clinical, surgical and pathological data. Pancreatic histology was used as the gold standard. For patients without surgery, the genetic profile served as the gold standard. Fifty-five CHI patients were examined by PET/CT (18F-DOPA n = 53, 68Ga-DOTANOC n = 18). Surgery was performed in 34 patients, no surgery in 21 patients. Fifty-one patients had a classifiable outcome, either by histology (n = 33, 22 focal lesions, 11 non-focal) or by genetics (n = 18, all non-focal). The predictive performance of 18F-DOPA PET/CT to identify focal CHI was identical by visual- and cut-off-based evaluation: sensitivity (95% CI) of 1 (0.85-1); specificity of 0.96 (0.82-0.99). The optimal 18F-DOPA PET SUV max ratio cut-off was 1.44 and the optimal 68Ga-DOTANOC PET SUV max cut-off was 6.77 g/ml. The area under the receiver operating curve was 0.98 (0.93-1) for 18F-DOPA PET vs. 0.71 (0.43-0.95) for 68Ga-DOTANOC PET (p PET/CT and 68Ga-DOTANOC PET/CT, respectively. 18F-DOPA PET/CT was excellent in predicting focal CHI and superior compared to 68Ga-DOTANOC PET/CT. Further use of 68GA-DOTANOC PET/CT in predicting focal CHI is discouraged.

  14. 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT scans as diagnostic tools in focal congenital hyperinsulinism. A blinded evaluation

    International Nuclear Information System (INIS)

    Dahl Christiansen, Charlotte; Helleskov Rasmussen, Annett; Petersen, Henrik; Lerberg Nielsen, Anne; Detlefsen, Soenke; Brusgaard, Klaus; Rasmussen, Lars; Hovendal, Claus; Melikyan, Maria; Ekstroem, Klas; Globa, Evgenia; Christesen, Henrik Thybo

    2018-01-01

    Focal congenital hyperinsulinism (CHI) is curable by surgery, which is why identification of the focal lesion is crucial. We aimed to determine the use of 18F-fluoro-dihydroxyphenylalanine (18F-DOPA) PET/CT vs. 68Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic-acid-1-Nal3 -octreotide (68Ga-DOTANOC) PET/CT as diagnostic tools in focal CHI. PET/CT scans of children with CHI admitted to Odense University Hospital between August 2005 and June 2016 were retrospectively evaluated visually and by their maximal standardized uptake values (SUV max ) by two independent examiners, blinded for clinical, surgical and pathological data. Pancreatic histology was used as the gold standard. For patients without surgery, the genetic profile served as the gold standard. Fifty-five CHI patients were examined by PET/CT (18F-DOPA n = 53, 68Ga-DOTANOC n = 18). Surgery was performed in 34 patients, no surgery in 21 patients. Fifty-one patients had a classifiable outcome, either by histology (n = 33, 22 focal lesions, 11 non-focal) or by genetics (n = 18, all non-focal). The predictive performance of 18F-DOPA PET/CT to identify focal CHI was identical by visual- and cut-off-based evaluation: sensitivity (95% CI) of 1 (0.85-1); specificity of 0.96 (0.82-0.99). The optimal 18F-DOPA PET SUV max ratio cut-off was 1.44 and the optimal 68Ga-DOTANOC PET SUV max cut-off was 6.77 g/ml. The area under the receiver operating curve was 0.98 (0.93-1) for 18F-DOPA PET vs. 0.71 (0.43-0.95) for 68Ga-DOTANOC PET (p < 0.03). In patients subjected to surgery, localization of the focal lesion was correct in 91%, and 100%, by 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT, respectively. 18F-DOPA PET/CT was excellent in predicting focal CHI and superior compared to 68Ga-DOTANOC PET/CT. Further use of 68GA-DOTANOC PET/CT in predicting focal CHI is discouraged. (orig.)

  15. 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT scans as diagnostic tools in focal congenital hyperinsulinism. A blinded evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Dahl Christiansen, Charlotte; Helleskov Rasmussen, Annett [Hans Christian Andersen Children' s Hospital, Odense University Hospital, Odense (Denmark); University of Southern Denmark, Department of Clinical Research, Odense (Denmark); Petersen, Henrik; Lerberg Nielsen, Anne [Odense University Hospital, Department of Nuclear Medicine, Odense (Denmark); Detlefsen, Soenke [University of Southern Denmark, Department of Clinical Research, Odense (Denmark); Odense University Hospital, Department of Pathology, Odense (Denmark); Brusgaard, Klaus [Odense University Hospital, Department of Clinical Genetics, Odense (Denmark); Rasmussen, Lars; Hovendal, Claus [Odense University Hospital, Department of Abdominal Surgery, Odense (Denmark); Melikyan, Maria [Endocrine Research Centre, Moscow (Russian Federation); Ekstroem, Klas [Karolinska Hospital, Astrid Lindgren Children' s Hospital, Stockholm (Sweden); Globa, Evgenia [MOH of Ukraine, Ukrainian Center of Endocrine Surgery, Endocrine Organs and Tissue Transplantation, Kyiv (Ukraine); Christesen, Henrik Thybo [Hans Christian Andersen Children' s Hospital, Odense University Hospital, Odense (Denmark); University of Southern Denmark, Department of Clinical Research, Odense (Denmark); Odense University Hospital, Odense Pancreas Center (OPAC), Odense (Denmark); Odense University Hospital, Department of Paediatrics, Odense C (Denmark)

    2018-02-15

    Focal congenital hyperinsulinism (CHI) is curable by surgery, which is why identification of the focal lesion is crucial. We aimed to determine the use of 18F-fluoro-dihydroxyphenylalanine (18F-DOPA) PET/CT vs. 68Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic-acid-1-Nal3 -octreotide (68Ga-DOTANOC) PET/CT as diagnostic tools in focal CHI. PET/CT scans of children with CHI admitted to Odense University Hospital between August 2005 and June 2016 were retrospectively evaluated visually and by their maximal standardized uptake values (SUV{sub max}) by two independent examiners, blinded for clinical, surgical and pathological data. Pancreatic histology was used as the gold standard. For patients without surgery, the genetic profile served as the gold standard. Fifty-five CHI patients were examined by PET/CT (18F-DOPA n = 53, 68Ga-DOTANOC n = 18). Surgery was performed in 34 patients, no surgery in 21 patients. Fifty-one patients had a classifiable outcome, either by histology (n = 33, 22 focal lesions, 11 non-focal) or by genetics (n = 18, all non-focal). The predictive performance of 18F-DOPA PET/CT to identify focal CHI was identical by visual- and cut-off-based evaluation: sensitivity (95% CI) of 1 (0.85-1); specificity of 0.96 (0.82-0.99). The optimal 18F-DOPA PET SUV{sub max} ratio cut-off was 1.44 and the optimal 68Ga-DOTANOC PET SUV{sub max} cut-off was 6.77 g/ml. The area under the receiver operating curve was 0.98 (0.93-1) for 18F-DOPA PET vs. 0.71 (0.43-0.95) for 68Ga-DOTANOC PET (p < 0.03). In patients subjected to surgery, localization of the focal lesion was correct in 91%, and 100%, by 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT, respectively. 18F-DOPA PET/CT was excellent in predicting focal CHI and superior compared to 68Ga-DOTANOC PET/CT. Further use of 68GA-DOTANOC PET/CT in predicting focal CHI is discouraged. (orig.)

  16. mathFISH, a Web Tool That Uses Thermodynamics-Based Mathematical Models for In Silico Evaluation of Oligonucleotide Probes for Fluorescence In Situ Hybridization▿ †

    OpenAIRE

    Yilmaz, L. Safak; Parnerkar, Shreyas; Noguera, Daniel R.

    2010-01-01

    Mathematical models of RNA-targeted fluorescence in situ hybridization (FISH) for perfectly matched and mismatched probe/target pairs are organized and automated in web-based mathFISH (http://mathfish.cee.wisc.edu). Offering the users up-to-date knowledge of hybridization thermodynamics within a theoretical framework, mathFISH is expected to maximize the probability of success during oligonucleotide probe design.

  17. mathFISH, a web tool that uses thermodynamics-based mathematical models for in silico evaluation of oligonucleotide probes for fluorescence in situ hybridization.

    Science.gov (United States)

    Yilmaz, L Safak; Parnerkar, Shreyas; Noguera, Daniel R

    2011-02-01

    Mathematical models of RNA-targeted fluorescence in situ hybridization (FISH) for perfectly matched and mismatched probe/target pairs are organized and automated in web-based mathFISH (http://mathfish.cee.wisc.edu). Offering the users up-to-date knowledge of hybridization thermodynamics within a theoretical framework, mathFISH is expected to maximize the probability of success during oligonucleotide probe design.

  18. ECR plasma diagnostics with Langmuir probe

    International Nuclear Information System (INIS)

    Kenez, L.; Biri, S.; Valek, A.

    2000-01-01

    Complete text of publication follows. An Electron Cyclotron Resonance (ECR) Ion Source is a tool to generate highly charged ions. The ion beam is extracted from the plasma chamber of the ECRIS. Higher charge states and beam intensities are the main objectives of ECR research. The heart of an ion source is the confined plasma which should be well known to reach those objectives. Information about the plasma can be obtained by plasma diagnostics methods. Langmuir probes were successfully used in case of other plasmas, e.g. TOKAMAK. Until last year plasma diagnostics at the ATOMKI ECRIS was performed by X-ray and visible light measurements. While X-ray measurements give global information, the Langmuir probe method can give information on the local plasma parameters. This is an advantage because the local parameters are not known in detail. By Langmuir probe measurements it is possible to get information on plasma density, plasma potential and partly on the electron temperature. From the experimental point of view a Langmuir probe is very simple. However, the precise positioning of the probe in the plasma chamber (HV platform, strong magnetic field, RF waves) is a difficult task. Also the theory of probes is complicated: the ECR plasma is a special one because the confining magnetic field is inhomogeneous, beside hot electrons it contains cold ions with different charge states and it is heated with high frequency EM waves. What can be measured with a probe is a voltage-current (U-I) characteristics. Figure 1 shows a typical U-I curve measured in our lab. As it can be seen in the figure the diagram has three main parts. An ion saturation current region (I.), an electron saturation current region (III.) and a transition region (II.) between them. These measurements were performed using two different power supplies to bias the probe to positive and negative voltage. To perform more precise U-I measurements we need a special power supply which is presently being built in

  19. Scanning optical microscope with long working distance objective

    Science.gov (United States)

    Cloutier, Sylvain G.

    2010-10-19

    A scanning optical microscope, including: a light source to generate a beam of probe light; collimation optics to substantially collimate the probe beam; a probe-result beamsplitter; a long working-distance, infinity-corrected objective; scanning means to scan a beam spot of the focused probe beam on or within a sample; relay optics; and a detector. The collimation optics are disposed in the probe beam. The probe-result beamsplitter is arranged in the optical paths of the probe beam and the resultant light from the sample. The beamsplitter reflects the probe beam into the objective and transmits resultant light. The long working-distance, infinity-corrected objective is also arranged in the optical paths of the probe beam and the resultant light. It focuses the reflected probe beam onto the sample, and collects and substantially collimates the resultant light. The relay optics are arranged to relay the transmitted resultant light from the beamsplitter to the detector.

  20. Cooperative scans

    NARCIS (Netherlands)

    M. Zukowski (Marcin); P.A. Boncz (Peter); M.L. Kersten (Martin)

    2004-01-01

    textabstractData mining, information retrieval and other application areas exhibit a query load with multiple concurrent queries touching a large fraction of a relation. This leads to individual query plans based on a table scan or large index scan. The implementation of this access path in most

  1. STM-SQUID probe microscope

    International Nuclear Information System (INIS)

    Hayashi, Tadayuki; Tachiki, Minoru; Itozaki, Hideo

    2007-01-01

    We have developed a STM-SQUID probe microscope. A high T C SQUID probe microscope was combined with a scanning tunneling microscope for investigation of samples at room temperature in air. A high permeability probe needle was used as a magnetic flux guide to improve the spatial resolution. The probe with tip radius of less than 100 nm was prepared by microelectropolishing. The probe was also used as a scanning tunneling microscope tip. Topography of the sample surface could be measured by the scanning tunneling microscope with high spatial resolution prior to observation by SQUID microscopy. The SQUID probe microscope image could be observed while keeping the distance from the sample surface to the probe tip constant. We observed a topographic image and a magnetic image of Ni fine pattern and also a magnetically recorded hard disk. Furthermore we have investigated a sample vibration method of the static magnetic field emanating from a sample with the aim of achieving a higher signal-to-noise (S/N) ratio

  2. Development of a virtual probe tip with an application to high aspect ratio microscale features

    International Nuclear Information System (INIS)

    Bauza, Marcin B.; Hocken, Robert J.; Smith, Stuart T.; Woody, Shane C.

    2005-01-01

    Nondestructive measurement of microscale features remains a challenging metrology problem. For example, to assess a high aspect ratio small hole it is currently common to cut a cross section and measure the features of interest using an atomic force microscope, scanning probe microscope, or scanning electron microscope. Typically, these metrology tools may be suitable for surface finish measurement but often lack the capability for dimensional metrology. The aim of this article is to discuss the development of a high aspect-ratio microscale probe for measurement of microscale features. A 700:1 high aspect ratio probe shank is fabricated with a 7 μm diameter, and attached at one end to an oscillator. The oscillator produces a standing wave in the oscillating probe shank as opposed to conventional probes that use a microscale sphere on the end of a comparatively rigid shank. As a result of the standing wave formed in steady state vibration, the free end of the shank generates an amplitude of oscillation greater than the probe shank diameter. Thus, the probe does not require a spherical ball to serve as the contact point and simply uses the contact diameter of the free end of the vibrating shank. This methodology is referred to as a virtual probe tip. The virtual probe tip in conjunction with a nanopositioning scanner is used to measure surface profile measurements over traverse lengths of 130 μm. In this article, results from profiles of a 500 nm step height and a ruby sphere of diameter 1 mm are presented. Experiments in this article indicate the ability to repeatedly resolve surface features of less than 5 nm while maintaining bandwidths greater than 1 kHz. Furthermore, adhesion problems often encountered with micrometer scaled probes were not observed during profile measurements with this virtual probe

  3. Investigation of voltages and electric fields in silicon semi 3D radiation detectors using Silvaco/ATLAS simulation tool and a scanning electron microscope

    CERN Document Server

    Palviainen, T; Tuuva, T; Eranen, S; Härkönen, J; Luukka, P; Tuovinen, E

    2006-01-01

    The structure of silicon semi three-dimensional radiation detector is simulated on purpose to find out its electrical characteristics such as the depletion voltage and electric field. Two-dimensional simulation results are compared to voltage and electric field measurements done by a scanning electron microscope.

  4. Thermal motion of a holographically trapped SPM-like probe

    International Nuclear Information System (INIS)

    Simpson, Stephen H; Hanna, Simon

    2009-01-01

    By holding a complex object in multiple optical traps, it may be harmonically bound with respect to both its position and its orientation. In this way a small probe, or nanotool, can be manipulated in three dimensions and used to measure and apply directed forces, in the manner of a scanning probe microscope. In this paper we evaluate the thermal motion of such a probe held in holographic optical tweezers, by solving the Langevin equation for the general case of a set of spherical vertices linked by cylindrical rods. The concept of a corner frequency, familiar from the case of an optically trapped sphere, is appropriately extended to represent a set of characteristic frequencies given by the eigenvalues of the product of the stiffness matrix and the inverse hydrodynamic resistance matrix of the tool. These eigenvalues may alternatively be interpreted as inverses of a set of characteristic relaxation times for the system. The approach is illustrated by reference to a hypothetical tool consisting of a triangular arrangement of spheres with a lateral probe. The characteristic frequencies and theoretical resolution of the device are derived; variations of these quantities with tool size and orientation and with the optical power distribution, are also considered.

  5. Probe Storage

    NARCIS (Netherlands)

    Gemelli, Marcellino; Abelmann, Leon; Engelen, Johannes Bernardus Charles; Khatib, M.G.; Koelmans, W.W.; Zaboronski, Olog; Campardo, Giovanni; Tiziani, Federico; Laculo, Massimo

    2011-01-01

    This chapter gives an overview of probe-based data storage research over the last three decades, encompassing all aspects of a probe recording system. Following the division found in all mechanically addressed storage systems, the different subsystems (media, read/write heads, positioning, data

  6. Cultural probes

    DEFF Research Database (Denmark)

    Madsen, Jacob Østergaard

    The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation.......The aim of this study was thus to explore cultural probes (Gaver, Boucher et al. 2004), as a possible methodical approach, supporting knowledge production on situated and contextual aspects of occupation....

  7. Radionuclide scanning

    International Nuclear Information System (INIS)

    Shapiro, B.

    1986-01-01

    Radionuclide scanning is the production of images of normal and diseased tissues and organs by means of the gamma-ray emissions from radiopharmaceutical agents having specific distributions in the body. The gamma rays are detected at the body surface by a variety of instruments that convert the invisible rays into visible patterns representing the distribution of the radionuclide in the body. The patterns, or images, obtained can be interpreted to provide or to aid diagnoses, to follow the course of disease, and to monitor the management of various illnesses. Scanning is a sensitive technique, but its specificity may be low when interpreted alone. To be used most successfully, radionuclide scanning must be interpreted in conjunction with other techniques, such as bone radiographs with bone scans, chest radiographs with lung scans, and ultrasonic studies with thyroid scans. Interpretation is also enhanced by providing pertinent clinical information because the distribution of radiopharmaceutical agents can be altered by drugs and by various procedures besides physiologic and pathologic conditions. Discussion of the patient with the radionuclide scanning specialist prior to the study and review of the results with that specialist after the study are beneficial

  8. Laser ablation ICPMS study of trace element chemistry in molybdenite coupled with scanning electron microscopy (SEM) - An important tool for identification of different types of mineralization

    Czech Academy of Sciences Publication Activity Database

    Pašava, J.; Svojtka, Martin; Veselovský, F.; Ďurišová, Jana; Ackerman, Lukáš; Pour, O.; Drábek, M.; Halodová, P.; Haluzová, Eva

    2016-01-01

    Roč. 72, č. 1 (2016), s. 874-895 ISSN 0169-1368 R&D Projects: GA ČR GA13-15390S Institutional support: RVO:67985831 Keywords : molybdenite * trace-element geochemistry * Laser Ablation Inductively Coupled Mass * spectrometry * scanning electron microscopy * nano- to micro-inclusions * Bohemian Massif * Uzbekistan Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.095, year: 2016

  9. Simultaneous fast scanning XRF, dark field, phase-, and absorption contrast tomography

    Science.gov (United States)

    Medjoubi, Kadda; Bonissent, Alain; Leclercq, Nicolas; Langlois, Florent; Mercère, Pascal; Somogyi, Andrea

    2013-09-01

    Scanning hard X-ray nanoprobe imaging provides a unique tool for probing specimens with high sensitivity and large penetration depth. Moreover, the combination of complementary techniques such as X-ray fluorescence, absorption, phase contrast and dark field imaging gives complete quantitative information on the sample structure, composition and chemistry. The multi-technique "FLYSCAN" data acquisition scheme developed at Synchrotron SOLEIL permits to perform fast continuous scanning imaging and as such makes scanning tomography techniques feasible in a time-frame well-adapted to typical user experiments. Here we present the recent results of simultaneous fast scanning multi-technique tomography performed at Soleil. This fast scanning scheme will be implemented at the Nanoscopium beamline for large field of view 2D and 3D multimodal imaging.

  10. CT Scan of Thirteen Natural Mummies Dating Back to the XVI-XVIII Centuries: An Emerging Tool to Investigate Living Conditions and Diseases in History.

    Directory of Open Access Journals (Sweden)

    Enrico Petrella

    Full Text Available To correlate the radiologic findings detected with computed tomography scan with anthropological data in 13 naturally mummified bodies discovered during works of recovery of an ancient church in a crypt in Roccapelago, in the Italian Apennines.From a group of about sixty not-intentionally mummified bodies, thirteen were selected to be investigated with volumetric computed tomography (CT. Once CT scan was performed, axial images were processed to gather MPR and Volume Rendering reconstructions. Elaborations of these images provided anthropometric measurements and a non-invasive analysis of the residual anatomical structures. For each body the grade of preservation and the eventual pathological changes were recorded. Furthermore, in order to identify nutritional and occupational markers, radiologic signs of bone tropism and degenerative changes were analysed and graded.Mummies included seven females and six males, with an estimated age ranging from 20 to 60 years. The first relevant finding identified was a general low grade of preservation, due to the lack of anatomic tissues different from bones, tendons and dehydrated skin. The low grade of preservation was related to the natural process of mummification. Analysing bone degenerative changes on CT scan, the majority of the bodies had significant occupational markers consisting of arthritis in the spine, lower limbs and shoulders even in young age. Few were the pathological findings identified. Among these, the most relevant included a severe bilateral congenital hip dysplasia and a wide osteolytic lesion involving left orbit and petrous bone that was likely the cause of death.Although the low grade of preservation of these mummies, the multidisciplinary approach of anthropologists and radiologists allowed several important advances in knowledge for the epidemiology of Roccapelago. First of all, a profile of living conditions was delineated. It included occupational and nutritional conditions

  11. Seismic scanning tunneling macroscope - Elastic simulations and Arizona mine test

    KAUST Repository

    Hanafy, Sherif M.; Schuster, Gerard T.

    2012-01-01

    Elastic seismic simulations and field data tests are used to validate the theory of a seismic scanning tunneling macroscope (SSTM). For nearfield elastic simulation, the SSTM results show superresolution to be better than λ/8 if the only scattered data are used as input data. If the direct P and S waves are muted then the resolution of the scatterer locations are within about λ/5. Seismic data collected in an Arizona tunnel showed a superresolution limit of at least λ/19. These test results are consistent with the theory of the SSTM and suggest that the SSTM can be a tool used by geophysicists as a probe for near-field scatterers.

  12. Mobile probes

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Jørgensen, Anna Neustrup; Noesgaard, Signe Schack

    2016-01-01

    A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed...... to in an interview. This method provided valuable insight into the contextual use, i.e. how did the online resource transfer to the work practice. However, the research team also found that mobile probes may provide the scaffolding necessary for individual and peer learning at a very local (intra-school) community...... level. This paper is an initial investigation of how the mobile probes process proved to engage teachers in their efforts to improve teaching. It also highlights some of the barriers emerging when applying mobile probes as a scaffold for learning....

  13. Optical probe

    International Nuclear Information System (INIS)

    Denis, J.; Decaudin, J.M.

    1984-01-01

    The probe includes optical means of refractive index n, refracting an incident light beam from a medium with a refractive index n1>n and reflecting an incident light beam from a medium with a refractive index n2 [fr

  14. Counting probe

    International Nuclear Information System (INIS)

    Matsumoto, Haruya; Kaya, Nobuyuki; Yuasa, Kazuhiro; Hayashi, Tomoaki

    1976-01-01

    Electron counting method has been devised and experimented for the purpose of measuring electron temperature and density, the most fundamental quantities to represent plasma conditions. Electron counting is a method to count the electrons in plasma directly by equipping a probe with the secondary electron multiplier. It has three advantages of adjustable sensitivity, high sensitivity of the secondary electron multiplier, and directional property. Sensitivity adjustment is performed by changing the size of collecting hole (pin hole) on the incident front of the multiplier. The probe is usable as a direct reading thermometer of electron temperature because it requires to collect very small amount of electrons, thus it doesn't disturb the surrounding plasma, and the narrow sweep width of the probe voltage is enough. Therefore it can measure anisotropy more sensitively than a Langmuir probe, and it can be used for very low density plasma. Though many problems remain on anisotropy, computer simulation has been carried out. Also it is planned to provide a Helmholtz coil in the vacuum chamber to eliminate the effect of earth magnetic field. In practical experiments, the measurement with a Langmuir probe and an emission probe mounted to the movable structure, the comparison with the results obtained in reverse magnetic field by using a Helmholtz coil, and the measurement of ionic sound wave are scheduled. (Wakatsuki, Y.)

  15. Scanning tunneling microscope with two-dimensional translator.

    Science.gov (United States)

    Nichols, J; Ng, K-W

    2011-01-01

    Since the invention of the scanning tunneling microscope (STM), it has been a powerful tool for probing the electronic properties of materials. Typically STM designs capable of obtaining resolution on the atomic scale are limited to a small area which can be probed. We have built an STM capable of coarse motion in two dimensions, the z- and x-directions which are, respectively, parallel and perpendicular to the tip. This allows us to image samples with very high resolution at sites separated by macroscopic distances. This device is a single unit with a compact design making it very stable. It can operate in either a horizontal or vertical configuration and at cryogenic temperatures.

  16. Scanning table

    CERN Multimedia

    1960-01-01

    Before the invention of wire chambers, particles tracks were analysed on scanning tables like this one. Today, the process is electronic and much faster. Bubble chamber film - currently available - (links can be found below) was used for this analysis of the particle tracks.

  17. Scan Statistics

    CERN Document Server

    Glaz, Joseph

    2009-01-01

    Suitable for graduate students and researchers in applied probability and statistics, as well as for scientists in biology, computer science, pharmaceutical science and medicine, this title brings together a collection of chapters illustrating the depth and diversity of theory, methods and applications in the area of scan statistics.

  18. DNA probes

    International Nuclear Information System (INIS)

    Castelino, J.

    1992-01-01

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with 32 P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism's genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens

  19. DNA probes

    Energy Technology Data Exchange (ETDEWEB)

    Castelino, J

    1993-12-31

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with {sup 32}P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism`s genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens 10 figs, 2 tabs

  20. Heavy ion beam probe (HIBP) diagnostics as a tool for investigations into the plasma turbulence and the local electric field of dense plasma

    Energy Technology Data Exchange (ETDEWEB)

    Krupnik, L.I.; Chmyga, A.A.; Komarov, A.D.; Kozachok, A.S.; Zhezhera, A.I. [Institute of Plasma Physics, NSC KIPT, 310108 Kharkov (Ukraine); Melnikov, A.V.; Eliseev, L.G.; Lysenko, S.E.; Mavrin, V.A.; Perfilov, S.V. [Institute of Nuclear Fusion, RRC ' Kurchatov Institute' , Moscow (Russian Federation); Hidalgo, C.; Ascasibar, E.; Estrada, T.; Liniers, M.; Ochando, M.A.; Pablos, J.L. de; Pedrosa, M.A.; Tabares, F. [Laboratorio Nacional de Fusion por Confinamiento Magnetico, Asociacion EURATOM-CIEMAT, 28040-Madrid (Spain)

    2011-07-01

    One of essential achievements of the Heavy Ion Beam Probe (HIBP) diagnostics is the possibility to use it for investigation of plasma confinement by measuring the fluctuations of electric field and plasma density; the method is based on the important role of the plasma electric fields. Both edge and core transport barriers are related to a large increase in the E*B sheared flows in a fusion device. In the TJ-II stellarator the HIBP diagnostics has recently been upgraded for two-point measurements with a good spatial (1 cm) and temporal (10 {mu}s) resolution of the plasma electric potential and density, as well as their fluctuations and poloidal component of electric field, E{sub p} equals ({phi}1 - {phi}2)/{Delta}r [V/cm]; these data give chance to extract the radial turbulent particle flux: {Gamma}(r) equals {Gamma}(Epol*Btor) equals {Gamma}(E*B). (authors)

  1. Diagnostic tools based on minor groove binder probe technology for rapid identification of vaccinal and field strains of canine parvovirus type 2b.

    Science.gov (United States)

    Decaro, Nicola; Martella, Vito; Elia, Gabriella; Desario, Costantina; Campolo, Marco; Buonavoglia, Domenico; Bellacicco, Anna Lucia; Tempesta, Maria; Buonavoglia, Canio

    2006-12-01

    TaqMan-based diagnostic tests have been developed for the identification of canine parvovirus type 2 (CPV-2) strains in the faeces of dogs with diarrhoea, including a minor groove binder (MGB) probe assay for identification of type 2-based vaccines and field strains (types 2a, 2b and 2c). Since type 2b vaccines have been licensed recently in Europe, two novel MGB assays were developed for discrimination between type 2b vaccines and field strains of CPV. Such assays have been found to be highly sensitive, specific and reproducible, allowing for simultaneous detection of type 2b vaccinal and field strains present in the same specimens. These new assays will help resolution of the diagnostic problems related to the detection of a type 2b strain in the faeces of dogs shortly after the administration of a type 2b vaccine.

  2. Double phi-Step theta-Scanning Technique for Spherical Near-Field Antenna Measurements

    DEFF Research Database (Denmark)

    Laitinen, Tommi

    2008-01-01

    Probe-corrected spherical near-field antenna measurements with an arbitrary probe set certain requirements on an applicable scanning technique. The computational complexity of the general high-order probe correction technique for an arbitrary probe, that is based on the Phi scanning, is O(N4...... a specific double Phi-step thetas scanning technique for spherical near-field antenna measurements. This technique not only constitutes an alternative spherical scanning technique, but it also enables formulating an associated probe correction technique for arbitrary probes with the computational complexity...

  3. Conductivity Probe

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air. The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air. The needles on the probe are 15 millimeters (0.6 inch) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  4. Scanning SQUID microscopy of a ferromanganese crust from the northwestern Pacific: Submillimeter scale magnetostratigraphy as a new tool for age determination and mapping of environmental magnetic parameters

    Science.gov (United States)

    Noguchi, A.; Oda, H.; Yamamoto, Y.; Usui, A.; Sato, M.; Kawai, J.

    2017-06-01

    Ferromanganese crusts record long-term deep-sea environmental changes. Thus, providing their reliable high-resolution age models is important. We applied a magnetostratigraphic technique to estimate the growth rate of a ferromanganese crust using scanning SQUID (superconducting quantum interference device) microscope (SSM). SSM is designed to map the magnetic field across thin sections with submillimeter resolution. The crust sample was taken from the Takuyo-Daigo Seamount, northwestern Pacific, and recorded a limited supply of dust and sediment from continents. After drift correction and removal of spike noises, the magnetic field values were stacked within the areas of high signal-to-noise ratios. By correlating the obtained profiles with a standard geomagnetic polarity timescale, we obtained an average growth rate of 3.37 ± 0.06 mm/Ma, which is consistent with that obtained by 10Be/9Be geochronology (2.93 ± 0.15 mm/Ma). S ratio mapping shows low values after 3 Ma, associated with voids between columnar structures.

  5. Optical methods and differential scanning calorimetry as a potential tool for discrimination of olive oils (extra virgin and mix with vegetable oils)

    Science.gov (United States)

    Nikolova, Kr.; Yovcheva, T.; Marudova, M.; Eftimov, T.; Bodurov, I.; Viraneva, A.; Vlaeva, I.

    2016-03-01

    Eleven samples from olive oil have been investigated using four physical methods - refractive index measurement, fluorescence spectra, color parameters and differential scanning colorimetry. In pomace olive oil (POO) and extra virgin olive oil (EVOO) the oleic acid (65.24 %-78.40 %) predominates over palmitic (10.47 %-15.07 %) and linoleic (5.26 %-13.92 %) acids. The fluorescence spectra contain three peaks related to oxidation products at about λ = (500-540) nm, chlorophyll content at about λ = (675-680) nm and non determined pigments at λ = (700-750) nm. The melting point for EVOO and POO is between -1 °C and -6 °C. In contrast, the salad olive oils melt between -24 °C and -30 °C. The refractive index for EVOO is lower than that for mixed olive oils. The proposed physical methods could be used for fast and simple detection of vegetable oils in EVOO without use of chemical substances. The experimental results are in accordance with those obtained by chemical analysis.

  6. Scanning holograms

    International Nuclear Information System (INIS)

    Natali, S.

    1984-01-01

    This chapter reports on the scanning of 1000 holograms taken in HOBC at CERN. Each hologram is triggered by an interaction in the chamber, the primary particles being pions at 340 GeV/c. The aim of the experiment is the study of charm production. The holograms, recorded on 50 mm film with the ''in line'' technique, can be analyzed by shining a parallel expanded laser beam through the film, obtaining immediately above it the real image of the chamber which can then be scanned and measured with a technique half way between emulsions and bubble chambers. The results indicate that holograms can be analyzed as quickly and reliably as in other visual techniques and that to them is open the same order of magnitude of large scale experiments

  7. Bone scans

    International Nuclear Information System (INIS)

    Hetherington, V.J.

    1989-01-01

    Oftentimes, in managing podiatric complaints, clinical and conventional radiographic techniques are insufficient in determining a patient's problem. This is especially true in the early stages of bone infection. Bone scanning or imaging can provide additional information in the diagnosis of the disorder. However, bone scans are not specific and must be correlated with clinical, radiographic, and laboratory evaluation. In other words, bone scanning does not provide the diagnosis but is an important bit of information aiding in the process of diagnosis. The more useful radionuclides in skeletal imaging are technetium phosphate complexes and gallium citrate. These compounds are administered intravenously and are detected at specific time intervals postinjection by a rectilinear scanner with minification is used and the entire skeleton can be imaged from head to toe. Minification allows visualization of the entire skeleton in a single image. A gamma camera can concentrate on an isolated area. However, it requires multiple views to complete the whole skeletal image. Recent advances have allowed computer augmentation of the data received from radionucleotide imaging. The purpose of this chapter is to present the current radionuclides clinically useful in podiatric patients

  8. 3D reconstruction of emergency cranial computed tomography scans as a tool in clinical forensic radiology after survived blunt head trauma--report of two cases.

    Science.gov (United States)

    Grassberger, M; Gehl, A; Püschel, K; Turk, E E

    2011-04-15

    When requested to evaluate surviving victims of blunt head trauma the forensic expert has to draw mainly on medical documentation from the time of hospital admission. In many cases these consist of written clinical records, radiographs and in some cases photographic documentation of the injuries. We report two cases of survived severe blunt head trauma where CT images, which had primarily been obtained for clinical diagnostic purposes, were used for forensic assessment. 3D reconstructions of the clinical CT-images yielded valuable information regarding the sequence, number and direction of the impacts to the head, their gross morphology and the inflicting weapon. We conclude that computed tomography and related imaging methods, along with their 3D reconstruction capabilities, provide a useful tool to approach questions in clinical forensic casework. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  9. Probe specificity

    International Nuclear Information System (INIS)

    Laget, J.M.

    1986-11-01

    Specificity and complementarity of hadron and electron probes must be systematically developed to answer three questions currently asked in intermediate energy nuclear physics: what is nucleus structure at short distances, what is nature of short range correlations, what is three body force nature [fr

  10. Quantitative ptychographic reconstruction by applying a probe constraint

    Science.gov (United States)

    Reinhardt, J.; Schroer, C. G.

    2018-04-01

    The coherent scanning technique X-ray ptychography has become a routine tool for high-resolution imaging and nanoanalysis in various fields of research such as chemistry, biology or materials science. Often the ptychographic reconstruction results are analysed in order to yield absolute quantitative values for the object transmission and illuminating probe function. In this work, we address a common ambiguity encountered in scaling the object transmission and probe intensity via the application of an additional constraint to the reconstruction algorithm. A ptychographic measurement of a model sample containing nanoparticles is used as a test data set against which to benchmark in the reconstruction results depending on the type of constraint used. Achieving quantitative absolute values for the reconstructed object transmission is essential for advanced investigation of samples that are changing over time, e.g., during in-situ experiments or in general when different data sets are compared.

  11. SCAN Technology

    DEFF Research Database (Denmark)

    Greene, Gretchen; Greene, Robert; Markvorsen, Steen

    1998-01-01

    A strategy for the reproduction (by milling in marble using a vertically moving spherical tool) of a given height function is found using a level curve analysis of the largest principal (upward pointing) curvature of the corresponding surface. Data fitting is applied to the discrete data set whic...

  12. Emergency Department Sickle Cell Assessment of Needs and Strengths (ED-SCANS), a Focus Group and Decision Support Tool Development Project

    Science.gov (United States)

    Tanabe, Paula; Reddin, Christopher; Thornton, Victoria L.; Todd, Knox H.; Wun, Ted; Lyons, John S.

    2010-01-01

    Objectives A decision support tool may guide emergency clinicians in recognizing assessment, analgesic and overall management, and health service delivery needs for patients with sickle cell disease (SCD) in the emergency department (ED). We aimed to identify data and process elements important in making decisions regarding evaluation and management of adult patients in the ED with painful episodes of sickle cell disease. Methods Qualitative methods using a series of focus groups and grounded theory were used. Eligible participants included adult clients with SCD, and emergency physicians and nurses with a minimum of one year of experience providing care to patients with SCD in the ED. Patients were recruited in conjunction with annual SCD meetings, and providers included clinicians who were and were not affiliated with sickle cell centers. Groups were conducted until saturation was reached, and included a total of two patient groups, three physician groups, and two nurse groups. Focus groups were held in New York, Durham, Chicago, New Orleans, and Denver. Clinician participants were asked the following three questions to guide the discussion: 1) what information would be important to know about patients with SCD in the ED setting to effectively care for them and help you identify patient analgesic, treatment, and referral needs? 2) what treatment decisions would you make with this information? and 3) what characteristics would a decision support tool need to have to make it meaningful and useful? Client participants were asked the same questions with re-wording to reflect what they believed providers should know to provide the best care, and what they should do with the information. All focus groups were audio taped and transcribed. The constant comparative method was used to analyze the data. Two coders independently coded participant responses and identified focal themes based on the key questions. An investigator and assistant independently reviewed the

  13. Cathodoluminescence in the scanning transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kociak, M., E-mail: mathieu.kociak@u-psud.fr [Laboratoire de Physique des Solides, Université Paris-SudParis-Sud, CNRS-UMR 8502, Orsay 91405 (France); Zagonel, L.F. [“Gleb Wataghin” Institute of Physics University of Campinas - UNICAMP, 13083-859 Campinas, São Paulo (Brazil)

    2017-05-15

    Cathodoluminescence (CL) is a powerful tool for the investigation of optical properties of materials. In recent years, its combination with scanning transmission electron microscopy (STEM) has demonstrated great success in unveiling new physics in the field of plasmonics and quantum emitters. Most of these results were not imaginable even twenty years ago, due to conceptual and technical limitations. The purpose of this review is to present the recent advances that broke these limitations, and the new possibilities offered by the modern STEM-CL technique. We first introduce the different STEM-CL operating modes and the technical specificities in STEM-CL instrumentation. Two main classes of optical excitations, namely the coherent one (typically plasmons) and the incoherent one (typically light emission from quantum emitters) are investigated with STEM-CL. For these two main classes, we describe both the physics of light production under electron beam irradiation and the physical basis for interpreting STEM-CL experiments. We then compare STEM-CL with its better known sister techniques: scanning electron microscope CL, photoluminescence, and electron energy-loss spectroscopy. We finish by comprehensively reviewing recent STEM-CL applications. - Highlights: • Reviews the field of STEM-CL. • Introduces the technical requirements and challenges for STEM-CL. • Introduces the different types of excitations probed by STEM-CL. • Gives comprehensive overview of the last fifteenth years in the field.

  14. Hepatobiliary scanning

    Energy Technology Data Exchange (ETDEWEB)

    Verdegaal, W P

    1978-01-01

    The use of hepatobiliary scintigraphy is discussed on the basis of personal observations with sup(99m)Tc-pyridoxylideneglutamate (sup(99m)Tc-PG). Hepatobiliary scintigraphy appears to be a useful tool in differentiating the causes of jaundice. Its value as a test for biliary reflux to the stomach and as a method to evaluate the function of intestinal and bilidigestive anastomoses needs further investigation.

  15. Probing the conformational energetics of alkyl thiols on gold surfaces by means of a morphing/steering non-equilibrium tool.

    Science.gov (United States)

    Piserchia, Andrea; Zerbetto, Mirco; Frezzato, Diego

    2015-03-28

    In this work we show that a non-equilibrium statistical tool based on Jarzynski's equality (JE) can be applied to achieve a sufficiently accurate mapping of the torsion free energy, bond-by-bond, for an alkyl thiol ligand tethered to a gold surface and sensing the presence of the surrounding cluster of similar chains. The strength of our approach is the employment of a strategy to let grow the internal energetics of the whole system (namely, the "energy morphing" stage recently presented by us in J. Comput. Chem., 2014, 35, 1865-1881) before initiating the rotational steering, which yields accurate results in terms of statistical uncertainties and bias on the free energy profiles. The work is mainly methodological and illustrates the feasibility of this kind of inspection on nanoscale molecular clusters with conformational flexibility. The outcomes for the archetype of self-assembled-monolayers considered here, a regular pattern of 10-carbon alkyl thiols on an ideal gold surface, give information on the conformational mobility of the ligands. Notably, such information is unlikely to be obtained by means of standard equilibrium techniques or by conventional molecular dynamics simulations.

  16. Scanning Quantum Cryogenic Atom Microscope

    Science.gov (United States)

    Yang, Fan; Kollár, Alicia J.; Taylor, Stephen F.; Turner, Richard W.; Lev, Benjamin L.

    2017-03-01

    Microscopic imaging of local magnetic fields provides a window into the organizing principles of complex and technologically relevant condensed-matter materials. However, a wide variety of intriguing strongly correlated and topologically nontrivial materials exhibit poorly understood phenomena outside the detection capability of state-of-the-art high-sensitivity high-resolution scanning probe magnetometers. We introduce a quantum-noise-limited scanning probe magnetometer that can operate from room-to-cryogenic temperatures with unprecedented dc-field sensitivity and micron-scale resolution. The Scanning Quantum Cryogenic Atom Microscope (SQCRAMscope) employs a magnetically levitated atomic Bose-Einstein condensate (BEC), thereby providing immunity to conductive and blackbody radiative heating. The SQCRAMscope has a field sensitivity of 1.4 nT per resolution-limited point (approximately 2 μ m ) or 6 nT /√{Hz } per point at its duty cycle. Compared to point-by-point sensors, the long length of the BEC provides a naturally parallel measurement, allowing one to measure nearly 100 points with an effective field sensitivity of 600 pT /√{Hz } for each point during the same time as a point-by-point scanner measures these points sequentially. Moreover, it has a noise floor of 300 pT and provides nearly 2 orders of magnitude improvement in magnetic flux sensitivity (down to 10-6 Φ0/√{Hz } ) over previous atomic probe magnetometers capable of scanning near samples. These capabilities are carefully benchmarked by imaging magnetic fields arising from microfabricated wire patterns in a system where samples may be scanned, cryogenically cooled, and easily exchanged. We anticipate the SQCRAMscope will provide charge-transport images at temperatures from room temperature to 4 K in unconventional superconductors and topologically nontrivial materials.

  17. Integrated microfluidic probe station.

    Science.gov (United States)

    Perrault, C M; Qasaimeh, M A; Brastaviceanu, T; Anderson, K; Kabakibo, Y; Juncker, D

    2010-11-01

    The microfluidic probe (MFP) consists of a flat, blunt tip with two apertures for the injection and reaspiration of a microjet into a solution--thus hydrodynamically confining the microjet--and is operated atop an inverted microscope that enables live imaging. By scanning across a surface, the microjet can be used for surface processing with the capability of both depositing and removing material; as it operates under immersed conditions, sensitive biological materials and living cells can be processed. During scanning, the MFP is kept immobile and centered over the objective of the inverted microscope, a few micrometers above a substrate that is displaced by moving the microscope stage and that is flushed continuously with the microjet. For consistent and reproducible surface processing, the gap between the MFP and the substrate, the MFP's alignment, the scanning speed, the injection and aspiration flow rates, and the image capture need all to be controlled and synchronized. Here, we present an automated MFP station that integrates all of these functionalities and automates the key operational parameters. A custom software program is used to control an independent motorized Z stage for adjusting the gap, a motorized microscope stage for scanning the substrate, up to 16 syringe pumps for injecting and aspirating fluids, and an inverted fluorescence microscope equipped with a charge-coupled device camera. The parallelism between the MFP and the substrate is adjusted using manual goniometer at the beginning of the experiment. The alignment of the injection and aspiration apertures along the scanning axis is performed using a newly designed MFP screw holder. We illustrate the integrated MFP station by the programmed, automated patterning of fluorescently labeled biotin on a streptavidin-coated surface.

  18. Environmental scan

    International Nuclear Information System (INIS)

    1988-01-01

    Trends in current affairs and public policy that emerged in 1988 are analyzed to provide a tool for Atomic Energy of Canada's decision makers. This issue provides a general overview of the economic and energy environments; and international review of nuclear policies, equipment orders, and trends that will position Canada and AECL within the global nuclear community; a precis of Canadian public opinion polls on economic, environmental and energy issues; a summary of major trends identifies by Canadian opinion leaders from the public and private sectors; a review of opinions and recommendations of influential Canadian policy institutes; a report on government policies and actions that affect AECL directly or indirectly; an analysis of new coverage by print and electronic media; a review of anti-nuclear organizations; and conclusions and recommendations

  19. Ultrafast scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Botkin, D.A. [California Univ., Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley Lab., CA (United States)

    1995-09-01

    I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

  20. Head CT scan

    Science.gov (United States)

    ... scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... head size in children Changes in thinking or behavior Fainting Headache, when you have certain other signs ...