WorldWideScience

Sample records for scanning probe technique

  1. 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

  2. Scanning probe microscopy techniques for mechanical characterization at nanoscale

    International Nuclear Information System (INIS)

    Passeri, D.; Anastasiadis, P.; Tamburri, E.; Gugkielmotti, V.; Rossi, M.

    2013-01-01

    Three atomic force microscopy (AFM)-based techniques are reviewed that allow one to conduct accurate measurements of mechanical properties of either stiff or compliant materials at a nanometer scale. Atomic force acoustic microscopy, AFM-based depth sensing indentation, and torsional harmonic AFM are briefly described. Examples and results of quantitative characterization of stiff (an ultrathin SeSn film), soft polymeric (polyaniline fibers doped with detonation nanodiamond) and biological (collagen fibers) materials are reported.

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

    Science.gov (United States)

    Bolker, Asaf; Saguy, Cecile; Kalish, Rafi

    2014-09-26

    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.

  4. 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.

  5. 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)

  6. 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

  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. 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...

  9. 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

  10. 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.

  11. 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

  12. 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

  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. 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.

  15. 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.

  16. 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...

  17. 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.)

  18. 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.)

  19. Probe Techniques. Introductory Remarks

    Energy Technology Data Exchange (ETDEWEB)

    Emeleus, K. G. [School of Physics and Applied Mathematics, Queen' s University, Belfast (United Kingdom)

    1968-04-15

    In this brief introduction to the session on probes, the history of theii development is first touched on briefly. Reference is then made to the significance of the work to be described by Medicus, for conductivity and recombination calculations, and by Lam and Su, for a wide range of medium and higher pressure plasmas. Finally, a number of other probe topics are mentioned, including multiple probes; probes in electronegative plasmas; resonance probes; probes in noisy discharges; probes as oscillation detectors; use of probes where space-charge is not negligible. (author)

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. 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...

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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…

  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 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...

  2. 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

  3. 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...

  4. 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...

  5. 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.

  6. 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...

  7. 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.

  8. 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...

  9. Automation of scanning technique by gamma radiation

    International Nuclear Information System (INIS)

    Aamira, Yahya

    2011-01-01

    The gamma scan technique is a nuclear test allowing the analysis of the internal mechanical properties of distillation columns used in petrochemical industries. Such technique is performed manually. So we propose in this work to automate the gamma scan procedure test by using a PLC. In addition, supervision and data acquisition interfaces are proposed.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. 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.

  20. 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

  1. 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

  2. Scanning reference electrode techniques in localized corrosion

    International Nuclear Information System (INIS)

    Isaacs, H.S.; Vyas, B.

    1979-04-01

    The principles, advantages, and implementations of scanning reference electrode techniques are reviewed. Data related to pitting, intergranular corrosion, welds and stress corrosion cracking are presented. The technique locates the position of localized corrosion and can be used to monitor the development of corrosion and changes in the corrosion rate under a wide range of conditions

  3. Nanolithography and nanochemistry: probe-related patterning techniques and chemical modification for nanometer-sized devices

    NARCIS (Netherlands)

    Wouters, D.; Schubert, U.S.

    2004-01-01

    The size regime for devices produced by photolithographic techniques is limited. Therefore, other patterning techniques have been intensively studied to create smaller structures. Scanning-probe-based patterning techniques, such as dip-pen lithography, local force-induced patterning, and local-probe

  4. 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

  5. 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

  6. 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...

  7. 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

  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. 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

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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)

  18. 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%.

  19. 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)

  20. 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.

  1. 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)

  2. 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)

  3. 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...

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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)

  10. 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

  11. Contrast bolus technique with rapid CT scanning

    International Nuclear Information System (INIS)

    Arnold, H.; Kuehne, D.; Rohr, W.; Heller, M.

    1981-01-01

    Twenty-three patients complying with the clinical criteria for brain death were studied by contrast-enhanced CT. In all but one, the great intracranial vessels escaped visualization; accordingly, angiography demonstrated cerebral circulatory arrest. In the remaining case, faint enhancement of the circle of Willis corresponded to angiographic demonstration of the proximal segments of cerebral arteris. Neither in normal brain nor in dead brain did slow CT scanning disclose any postcontrast increase in parenchymal attenuation. An improved technique is proposed to demonstrate the transit of the contrast bolus by rapid CT with image splitting. If cerebral blood flow is preserved, the grey and white matter will enhance significantly following administration of contrast medium. Vice versa, the absence of enhancement confirms brain death, even in instances in which the great cerebral vessels are obscured by hemorrhage or other extensive lesions. Two additional cases of brain death were evaluated by rapid CT scanning. As to brain death, the technique obviates the need for angiography or radionuclide angiography, usually applied in prospective organ donors, because its informative content is superior to that of either method. The CT technique described affords a reliable and safe diagnosis of brain death, and can be interpreted easily. (orig.)

  12. A New Technique for Scanning the Pancreas

    Energy Technology Data Exchange (ETDEWEB)

    Ephraiem, K. H. [Rotterdamsch Radio-Therapeutisch Instituut, Rotterdam (Netherlands)

    1969-05-15

    The difficulties in visualizing the pancreas are partly caused by the high uptake of seleno-methionine in the liver. A simple technique has been developed to prevent data registration during the time the detector is moving above the liver. The technique is based on the fact that both {sup 75}Se and {sup 99m}Tc emit gamma rays of 140-keV energy. The pulses, normally going from the single-channel analyser to the registrating units, are deviated through a ratemeter to an API contactless optical meter relay (model API-compack I) and then passed on to the registrating units. The patient is given the normal dose of Se-methionine and everything is prepared for normal pancreas scanning with only one exception: The window of the single-channel analyser is tuned in on the 140-keV photopeak. The patient is given 2 mCi of {sup 99m}Tc colloid intravenously and the controls on the meter relay are adjusted in such a way that no pulse from the single-channel analyser passes to the registrating units unless the activity is beneath the activity level in the liver. Then the scanning machine is started. The author developed this inexpensive technique to help smaller clinical isotope laboratories which cannot afford the combination of a gamma camera with a special-purpose computer. (author)

  13. 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.

  14. Probing droplets on superhydrophobic surfaces by synchrotron radiation scattering techniques

    KAUST Repository

    Accardo, Angelo

    2014-06-10

    Droplets on artificially structured superhydrophobic surfaces represent quasi contact-free sample environments which can be probed by X-ray microbeams and nanobeams in the absence of obstructing walls. This review will discuss basic surface wettability concepts and introduce the technology of structuring surfaces. Quasi contact-free droplets are compared with contact-free droplets; processes related to deposition and evaporation on solid surfaces are discussed. Droplet coalescence based on the electrowetting effect allows the probing of short-time mixing and reaction processes. The review will show for several materials of biological interest that structural processes related to conformational changes, nucleation and assembly during droplet evaporation can be spatially and temporally resolved by raster-scan diffraction techniques. Orientational ordering of anisotropic materials deposited during solidification at pinning sites facilitates the interpretation of structural data. 2014 International Union of Crystallography.

  15. Probing droplets on superhydrophobic surfaces by synchrotron radiation scattering techniques

    KAUST Repository

    Accardo, Angelo; Di Fabrizio, Enzo M.; Limongi, Tania; Marinaro, Giovanni; Riekel, Christian

    2014-01-01

    Droplets on artificially structured superhydrophobic surfaces represent quasi contact-free sample environments which can be probed by X-ray microbeams and nanobeams in the absence of obstructing walls. This review will discuss basic surface wettability concepts and introduce the technology of structuring surfaces. Quasi contact-free droplets are compared with contact-free droplets; processes related to deposition and evaporation on solid surfaces are discussed. Droplet coalescence based on the electrowetting effect allows the probing of short-time mixing and reaction processes. The review will show for several materials of biological interest that structural processes related to conformational changes, nucleation and assembly during droplet evaporation can be spatially and temporally resolved by raster-scan diffraction techniques. Orientational ordering of anisotropic materials deposited during solidification at pinning sites facilitates the interpretation of structural data. 2014 International Union of Crystallography.

  16. 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.

  17. 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.

  18. 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.

  19. Com-scan techniques for material evaluation

    International Nuclear Information System (INIS)

    Jayakumar, T.K.; Naik, A.D.

    1996-01-01

    Presently a variety of products at various stages of production are being tested using NDT methods for ensuring their quality. The conventional NDT methods such as RT, UT, PT, MPT along with acoustic emission techniques are often employed for the purpose. However, the ever increasing demands for a comprehensive quality assurance of products necessitates newer avenues in testing methods to overcome certain inadequacies of conventional testing. This paper proposes Compton back-scatter technique as an additional alternative NDT tool for various measurements. When the radiation strikes material a small percentage of incident radiation scatters back with reduced energy. The back-scattered radiation is picked up by a digital backscatter gauge and analysed. The paper discusses experimental work carried out at the laboratory consisting of parameter evaluation, source detector geometry, back-scatter response for material, area effects, thickness and blockage measurements. The paper briefly discusses on-stream measurements carried out with the above experimental gauge. The paper deals with selection and comparison of measurements with those of ultrasonics. It also discusses the advantages of the radiation back-scatter testing. The paper recommends Com-scan back-scatter technique as a supplementary tool along with conventional testing. (author)

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  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. Structural Modeling Using "Scanning and Mapping" Technique

    Science.gov (United States)

    Amos, Courtney L.; Dash, Gerald S.; Shen, J. Y.; Ferguson, Frederick; Noga, Donald F. (Technical Monitor)

    2000-01-01

    Supported by NASA Glenn Center, we are in the process developing a structural damage diagnostic and monitoring system for rocket engines, which consists of five modules: Structural Modeling, Measurement Data Pre-Processor, Structural System Identification, Damage Detection Criterion, and Computer Visualization. The function of the system is to detect damage as it is incurred by the engine structures. The scientific principle to identify damage is to utilize the changes in the vibrational properties between the pre-damaged and post-damaged structures. The vibrational properties of the pre-damaged structure can be obtained based on an analytic computer model of the structure. Thus, as the first stage of the whole research plan, we currently focus on the first module - Structural Modeling. Three computer software packages are selected, and will be integrated for this purpose. They are PhotoModeler-Pro, AutoCAD-R14, and MSC/NASTRAN. AutoCAD is the most popular PC-CAD system currently available in the market. For our purpose, it plays like an interface to generate structural models of any particular engine parts or assembly, which is then passed to MSC/NASTRAN for extracting structural dynamic properties. Although AutoCAD is a powerful structural modeling tool, the complexity of engine components requires a further improvement in structural modeling techniques. We are working on a so-called "scanning and mapping" technique, which is a relatively new technique. The basic idea is to producing a full and accurate 3D structural model by tracing on multiple overlapping photographs taken from different angles. There is no need to input point positions, angles, distances or axes. Photographs can be taken by any types of cameras with different lenses. With the integration of such a modeling technique, the capability of structural modeling will be enhanced. The prototypes of any complex structural components will be produced by PhotoModeler first based on existing similar

  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. 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)

  10. 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.

  11. 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....

  12. 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

  13. New directions in point-contact spectroscopy based on scanning tunneling microscopy techniques (Review Article)

    International Nuclear Information System (INIS)

    Tartaglini, E.; Verhagen, T.G.A.; Galli, F.; Trouwborst, M.L.; Aarts, J.; Van-Ruitebbeek, J.M.; Muller, R.; Shiota, T.

    2013-01-01

    Igor Yanson showed 38 years ago for the first time a point-contact measurement where he probed the energy resolved spectroscopy of the electronic scattering inside the metal. Since this first measurement, the pointcontact spectroscopy (PCS) technique improved enormously. The application of the scanning probe microscopy (SPM) techniques in the late 1980s allowed achieving contacts with a diameter of a single atom. With the introduction of the mechanically controlled break junction technique, even spectroscopy on freely suspended chains of atoms could be performed. In this paper, we briefly review the current developments of PCS and show recent experiments in advanced scanning PCS based on SPM techniques. We describe some results obtained with both needle-anvil type of point contacts and scanning tunneling microscopy (STM). We also show our first attempt to lift up with a STM a chain of single gold atoms from a Au(110) surface.

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. Probing droplets on superhydrophobic surfaces by synchrotron radiation scattering techniques

    Energy Technology Data Exchange (ETDEWEB)

    Accardo, Angelo [Istituto Italiano di Tecnologia, Via Morego 30, Genova 16163 (Italy); Di Fabrizio, Enzo [KAUST (King Abdullah University of Science and Technology), Jeddah (Saudi Arabia); BIONEM Lab at University Magna Graecia, Campus Salvatore Venuta, Viale Europa 88100, Germaneto-Catanzaro (Italy); Limongi, Tania [KAUST (King Abdullah University of Science and Technology), Jeddah (Saudi Arabia); Marinaro, Giovanni [Istituto Italiano di Tecnologia, Via Morego 30, Genova 16163 (Italy); European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France); Riekel, Christian, E-mail: riekel@esrf.fr [European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)

    2014-06-10

    A comprehensive review about the use of micro- and nanostructured superhydrophobic surfaces as a tool for in situ X-ray scattering investigations of soft matter and biological materials. Droplets on artificially structured superhydrophobic surfaces represent quasi contact-free sample environments which can be probed by X-ray microbeams and nanobeams in the absence of obstructing walls. This review will discuss basic surface wettability concepts and introduce the technology of structuring surfaces. Quasi contact-free droplets are compared with contact-free droplets; processes related to deposition and evaporation on solid surfaces are discussed. Droplet coalescence based on the electrowetting effect allows the probing of short-time mixing and reaction processes. The review will show for several materials of biological interest that structural processes related to conformational changes, nucleation and assembly during droplet evaporation can be spatially and temporally resolved by raster-scan diffraction techniques. Orientational ordering of anisotropic materials deposited during solidification at pinning sites facilitates the interpretation of structural data.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. Radio techniques for probing the terrestrial ionosphere.

    Science.gov (United States)

    Hunsucker, R. D.

    The subject of the book is a description of the basic principles of operation, plus the capabilities and limitations of all generic radio techniques employed to investigate the terrestrial ionosphere. The purpose of this book is to present to the reader a balanced treatment of each technique so they can understand how to interpret ionospheric data and decide which techniques are most effective for studying specific phenomena. The first two chapters outline the basic theory underlying the techniques, and each following chapter discusses a separate technique. This monograph is entirely devoted to techniques in aeronomy and space physics. The approach is unique in its presentation of the principles, capabilities and limitations of the most important presently used radio techniques. Typical examples of data are shown for the various techniques, and a brief historical account of the technique development is presented. An extended annotated bibliography of the salient papers in the field is included.

  7. 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

  8. A Hall probe technique for characterizing high-temperature superconductors

    International Nuclear Information System (INIS)

    Zhang, J.; Sheldon, P.; Ahrenkiel, R.K.

    1992-01-01

    Thin-film GaAs Hall probes were fabricated by molecular beam epitaxy technology. A contactless technique was developed to characterize thin-film, high-temperature superconducting (HTSC) materials. The Hall probes detected the ac magnetic flux penetration through the high-temperature superconducting materials. The Hall detector has advantages over the mutual inductance magnetic flux detector

  9. 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.

  10. 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

  11. 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...

  12. 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....

  13. Maximizing Reading Narrative Text Ability by Probing Prompting Learning Technique

    Directory of Open Access Journals (Sweden)

    Wiwied Pratiwi

    2017-12-01

    Full Text Available The objective of this research was to know whether Probing Prompting Learning Technique can be used to get the maximum effect of students’ reading narrative ability in teaching and learning process. This research was applied collaborative action reEsearch, this research was done in two cycle. The subject of this research was 23 students at tenth grade of SMA Kartikatama Metro. The result of the research showed that the Probing Prompting Learning Technique is useful and effective to help students get maximum effect of their reading. Based on the results of the questionnaire obtained an average percentage of 95%, it indicated that application of Probing Prompting Learning Technique in teaching l reading was appropriately applied. In short that students’ responses toward Probing Prompting Learning Technique in teaching reading was positive. In conclusion, Probing Prompting Learning Technique can get maximum effect of students’ reading ability. In relation to the result of the reserach, some suggestion are offered to english teacher, that  the use of Probing Prompting learning Technique in teaching reading will get the maximum effect of students’ reading abilty.

  14. 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)

  15. 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.

  16. 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)

  17. 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

  18. High resolution techniques using scanning proton microprobe (SPM)

    International Nuclear Information System (INIS)

    Cholewa, M.; Saint, A.; Prawer, S.; Laird, J.S.; Legge, G.J.F.; Bardos, R.A.; Moorhead, G.F.; Taylor, G.N.; Stuart, S.A.; Howard, J.

    1994-01-01

    The very high resolution (down to 50 nm) achieved with low beam currents (fA) in a scanning ion microprobe have lead to many nondestructive techniques of microanalysis. This paper discusses recent developments and applications in the use of 3-D STIM (scanning transmission ion microscopy) Tomography, channeling STIM and IBIC (ion beam induced charge). (orig.)

  19. 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.

  20. 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.

  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. 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.

  3. 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....

  4. 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

  5. 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.

  6. 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...

  7. Combined Scanning Nanoindentation and Tunneling Microscope Technique by Means of Semiconductive Diamond Berkovich Tip

    International Nuclear Information System (INIS)

    Lysenko, O; Novikov, N; Gontar, A; Grushko, V; Shcherbakov, A

    2007-01-01

    A combined Scanning Probe Microscope (SPM) - nanoindentation instrument enables submicron resolution indentation tests and in-situ scanning of structure surfaces. A newly developed technique is based on the scanning tunneling microscopy (STM) with integrated Berkovich diamond semiconductive tip. Diamond tips for a combined SPM were obtained using the developed procedure including the synthesis of the semiconductive borondoped diamond monocrystals by the temperature gradient method at high pressure - high temperature conditions and fabrication of the tips from these crystals considering their zonal structure. Separately grown semiconductive diamond single crystals were studied in order to find the best orientation of diamond crystals. Optimal scanning characteristics and experimental data errors were calculated by an analysis of the general functional dependence of the tunneling current from properties of the tip and specimen. Tests on the indentation and scanning of the gold film deposited on the silicon substrate employing the fabricated tips demonstrated their usability, acceptable resolution and sensitivity

  8. Functional scanning probes for sensing, actuation and deposition

    NARCIS (Netherlands)

    Geerlings, J.

    2016-01-01

    The imaging of objects by standard bright field microscopy is limited by the wavelength of light. A technique that allows for a higher resolution is atomic force microscopy (AFM). In this technique the topography of a surface is mapped by measuring the force acting on an extremely sharp tip when it

  9. New scanning technique for the optical vortex microscope.

    Science.gov (United States)

    Augustyniak, Ireneusz; Popiołek-Masajada, Agnieszka; Masajada, Jan; Drobczyński, Sławomir

    2012-04-01

    In the optical vortex microscopy the focused Gaussian beam with optical vortex scans a sample. An optical vortex can be introduced into a laser beam with the use of a special optical element--a vortex lens. When moving the vortex lens, the optical vortex changes its position inside the spot formed by a focused laser beam. This effect can be used as a new precise scanning technique. In this paper, we study the optical vortex behavior at the sample plane. We also estimate if the new scanning technique results in observable effects that could be used for a phase object detection.

  10. 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

  11. 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

  12. 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)

  13. 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)

  14. 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)

  15. 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.

  16. Examination of irradiated fuel elements using gamma scanning technique

    International Nuclear Information System (INIS)

    Ichim, O.; Mincu, M.; Man, I.; Stanica, M.

    2016-01-01

    The purpose of this paper is to validate the gamma scanning technique used to calculate the activity of gamma fission products from CANDU/TRIGA irradiated fuel elements. After a short presentation of the equipments used and their characteristics, the paper describes the calibration technique for the devices and how computed tomography reconstruction is done. Following the previously mentioned steps is possible to obtain the axial and radial profiles and the computed tomography reconstruction for calibration sources and for the irradiated fuel elements. The results are used to validate the gamma scanning techniques as a non-destructive examination method. The gamma scanning techniques will be used to: identify the fission products in the irradiated CANDU/TRIGA fuel elements, construct the axial and radial distributions of fission products, get the distribution in cross section through computed tomography reconstruction, and determine the nuclei number and the fission products activity of the irradiated CANDU/TRIGA fuel elements. (authors)

  17. 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

  18. Magnetically scanned proton therapy beams: rationales and techniques

    International Nuclear Information System (INIS)

    Jones, D.T.L.; Schreuder, A.N.

    2000-01-01

    Perhaps the most important advantages of beam scanning systems for proton therapy in comparison with conventional passive beam spreading systems are: (1) Intensity modulation and inverse planning are possible. (2) There is negligible reduction in the range of the beam. (3) Integral dose is reduced as dose conformation to the proximal edge of the lesion is possible. (4) In principle no field-specific modifying devices are required. (5) There is less activation of the surroundings. (6) Scanning systems axe almost infinitely flexible. The main disadvantages include: (1) Scanning systems are more complicated and therefore potentially less reliable and more dangerous. (2) The development of such systems is more demanding in terms of cost, time and manpower. (3) More stable beams are required. (4) Dose and beam position monitoring are more difficult. (5) The problems associated with patient and organ movement axe more severe. There are several techniques which can be used for scanning. For lateral beam spreading, circular scanning (wobbling) or linear scanning can be done. In the latter case the beam can be scanned continuously or in a discrete fashion (spot scanning). Another possibility is to undertake the fastest scan in one dimension (strip scanning) and translate the patient or the scanning magnet in the other dimension. Depth variation is achieved by interposing degraders in the beam (cyclotrons) or by changing the beam energy (synchrotrons). The aim of beam scanning is to deliver a predetermined dose at any point in the body. Special safety precautions must be taken because of the high instantaneous dose rates. The beam position and the dose delivered at each point must be accurately and redundantly determined. (author)

  19. Improved analysis techniques for cylindrical and spherical double probes

    Energy Technology Data Exchange (ETDEWEB)

    Beal, Brian; Brown, Daniel; Bromaghim, Daron [Air Force Research Laboratory, 1 Ara Rd., Edwards Air Force Base, California 93524 (United States); Johnson, Lee [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, California 91109 (United States); Blakely, Joseph [ERC Inc., 1 Ara Rd., Edwards Air Force Base, California 93524 (United States)

    2012-07-15

    A versatile double Langmuir probe technique has been developed by incorporating analytical fits to Laframboise's numerical results for ion current collection by biased electrodes of various sizes relative to the local electron Debye length. Application of these fits to the double probe circuit has produced a set of coupled equations that express the potential of each electrode relative to the plasma potential as well as the resulting probe current as a function of applied probe voltage. These equations can be readily solved via standard numerical techniques in order to determine electron temperature and plasma density from probe current and voltage measurements. Because this method self-consistently accounts for the effects of sheath expansion, it can be readily applied to plasmas with a wide range of densities and low ion temperature (T{sub i}/T{sub e} Much-Less-Than 1) without requiring probe dimensions to be asymptotically large or small with respect to the electron Debye length. The presented approach has been successfully applied to experimental measurements obtained in the plume of a low-power Hall thruster, which produced a quasineutral, flowing xenon plasma during operation at 200 W on xenon. The measured plasma densities and electron temperatures were in the range of 1 Multiplication-Sign 10{sup 12}-1 Multiplication-Sign 10{sup 17} m{sup -3} and 0.5-5.0 eV, respectively. The estimated measurement uncertainty is +6%/-34% in density and +/-30% in electron temperature.

  20. 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.

  1. 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.

  2. Scanning probe and optical tweezer investigations of biomolecular interactions

    International Nuclear Information System (INIS)

    Rigby-Singleton, Shellie

    2002-01-01

    A complex array of intermolecular forces controls the interactions between and within biological molecules. The desire to empirically explore the fundamental forces has led to the development of several biophysical techniques. Of these, the atomic force microscope (AFM) and the optical tweezers have been employed throughout this thesis to monitor the intermolecular forces involved in biomolecular interactions. The AFM is a well-established force sensing technique capable of measuring biomolecular interactions at a single molecule level. However, its versatility has not been extrapolated to the investigation of a drug-enzyme complex. The energy landscape for the force induced dissociation of the DHFR-methotrexate complex was studied. Revealing an energy barrier to dissociation located ∼0.3 nm from the bound state. Unfortunately, the AFM has a limited range of accessible loading rates and in order to profile the complete energy landscape alternative force sensing instrumentation should be considered, for example the BFP and optical tweezers. Thus, this thesis outlines the development and construction an optical trap capable of measuring intermolecular forces between biomolecules at the single molecule level. To demonstrate the force sensing abilities of the optical set up, proof of principle measurements were performed which investigate the interactions between proteins and polymer surfaces subjected to varying degrees of argon plasma treatment. Complementary data was gained from measurements performed independently by the AFM. Changes in polymer resistance to proteins as a response to changes in polymer surface chemistry were detected utilising both AFM and optical tweezers measurements. Finally, the AFM and optical tweezers were employed as ultrasensitive biosensors. Single molecule investigations of the antibody-antigen interaction between the cardiac troponin I marker and its complementary antibody, reveals the impact therapeutic concentrations of heparin have

  3. 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.

  4. 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.

  5. Spatial Angular Compounding Technique for H-Scan Ultrasound Imaging.

    Science.gov (United States)

    Khairalseed, Mawia; Xiong, Fangyuan; Kim, Jung-Whan; Mattrey, Robert F; Parker, Kevin J; Hoyt, Kenneth

    2018-01-01

    H-Scan is a new ultrasound imaging technique that relies on matching a model of pulse-echo formation to the mathematics of a class of Gaussian-weighted Hermite polynomials. This technique may be beneficial in the measurement of relative scatterer sizes and in cancer therapy, particularly for early response to drug treatment. Because current H-scan techniques use focused ultrasound data acquisitions, spatial resolution degrades away from the focal region and inherently affects relative scatterer size estimation. Although the resolution of ultrasound plane wave imaging can be inferior to that of traditional focused ultrasound approaches, the former exhibits a homogeneous spatial resolution throughout the image plane. The purpose of this study was to implement H-scan using plane wave imaging and investigate the impact of spatial angular compounding on H-scan image quality. Parallel convolution filters using two different Gaussian-weighted Hermite polynomials that describe ultrasound scattering events are applied to the radiofrequency data. The H-scan processing is done on each radiofrequency image plane before averaging to get the angular compounded image. The relative strength from each convolution is color-coded to represent relative scatterer size. Given results from a series of phantom materials, H-scan imaging with spatial angular compounding more accurately reflects the true scatterer size caused by reductions in the system point spread function and improved signal-to-noise ratio. Preliminary in vivo H-scan imaging of tumor-bearing animals suggests this modality may be useful for monitoring early response to chemotherapeutic treatment. Overall, H-scan imaging using ultrasound plane waves and spatial angular compounding is a promising approach for visualizing the relative size and distribution of acoustic scattering sources. Copyright © 2018 World Federation for Ultrasound in Medicine and Biology. Published by Elsevier Inc. All rights reserved.

  6. 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 ...

  7. 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.

  8. 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.

  9. 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.

  10. High sensitivity probe absorption technique for time-of-flight ...

    Indian Academy of Sciences (India)

    Abstract. We report on a phase-sensitive probe absorption technique with high sen- sitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms.

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. Application of the iterative probe correction technique for a high-order probe in spherical near-field antenna measurements

    DEFF Research Database (Denmark)

    Laitinen, Tommi; Pivnenko, Sergey; Breinbjerg, Olav

    2006-01-01

    An iterative probe-correction technique for spherical near-field antenna measurements is examined. This technique has previously been shown to be well-suited for non-ideal first-order probes. In this paper, its performance in the case of a high-order probe (a dual-ridged horn) is examined....

  17. 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.

  18. 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.

  19. 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.

  20. Alternative technique to neutron probe calibration in situ

    International Nuclear Information System (INIS)

    Encarnacao, F.; Carneiro, C.; Dall'Olio, A.

    1990-01-01

    An alternative technique of neutron probe calibration in situ was applied for Podzolic soil. Under field condition, the neutron probe calibration was performed using a special arrangement that prevented the lateral movement of water around the access tube of the neutron probe. During the experiments, successive amounts of water were uniformly infiltrated through the soil profile. Two plots were set to study the effect of the plot dimension on the slope of the calibration curve. The results obtained shown that the amounts of water transferred to the soil profile were significantly correlated to the integrals of count ratio along the soil profile on both plots. In consequence, the slope of calibration curve in field condition was determined. (author)

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. A Continuous Dynamic Traffic Assignment Model From Plate Scanning Technique

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, A.; Gallego, I.; Sanchez-Cambronero, S.; Ruiz-Ripoll, L.; Barba, R.M.

    2016-07-01

    This paper presents a methodology for the dynamic estimation of traffic flows on all links of a network from observable field data assuming the first-in-first-out (FIFO) hypothesis. The traffic flow intensities recorded at the exit of the scanned links are propagated to obtain the flow waves on unscanned links. For that, the model calculates the flow-cost functions through information registered with the plate scanning technique. The model also responds to the concern about the parameter quality of flow-cost functions to replicate the real traffic flow behaviour. It includes a new algorithm for the adjustment of the parameter values to link characteristics when its quality is questionable. For that, it is necessary the a priori study of the location of the scanning devices to identify all path flows and to measure travel times in all links. A synthetic network is used to illustrate the proposed method and to prove its usefulness and feasibility. (Author)

  6. 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.

  7. 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...

  8. 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)

  9. Radioactive diffusion gaseous probe technique for study adsorbent structure inhomogeneity

    International Nuclear Information System (INIS)

    Zyuzin, A.Yu.; Korobkov, V.I.; Bekman, I.N.

    1990-01-01

    One of the versions of the method of diffusion gaseous probe - method of longitudinal shear in combination with autoradiography (ARG) - was used for characterising sorbents and catalysts, which are considered to be promising for reprocessing of sulfur-containing natural gases. Hydrogen sulfide, labelled with 35 S was used as diffusion radioactive probe. Zeolite granules of 4A type and granulated adsorbents on the basis of CR and AM aluminium oxides, which are industrial catalysts of Clauss reaction developed at SNEA company, were used as objects under investigation. It is shown that technique for fabrication of 4A zeolite granules leads to asymmetrical pore distribution over the granule diameter. Technique for AM granule fabrication leads to occuRrence of local inhomogeneities of the structure in the form of narrow coaxial rings with decreased or increased local adsorption ability. Granules of adsorbent of CR type are characterized by rather homogeneous structure. It is recommended to use the mentioned method for industrial adsorbent diagnosis

  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. 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%.

  16. 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.

  17. A Small Crack Length Evaluation Technique by Electronic Scanning

    International Nuclear Information System (INIS)

    Cho, Yong Sang; Kim, Jae Hoon

    2009-01-01

    The results of crack evaluation by conventional UT(Ultrasonic Test)is highly depend on the inspector's experience or knowledge of ultrasound. Phased array UT system and its application methods for small crack length evaluation will be a good alternative method which overcome present UT weakness. This study was aimed at checking the accuracy of crack length evaluation method by electronic scanning and discuss about characteristics of electronic scanning for crack length evaluation. Especially ultrasonic phased array with electronic scan technique was used in carrying out both sizing and detect ability of crack as its length changes. The response of ultrasonic phased array was analyzed to obtain the special method of determining crack length without moving the transducer and detectability of crack minimal length and depth from the material. A method of crack length determining by electronic scanning for the small crack is very real method which has it's accuracy and verify the effectiveness of method compared to a conventional crack length determination

  18. 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.)

  19. 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.

  20. Near-Field to Far-Field Transformation Techniques with Spiral Scannings: A Comprehensive Review

    Directory of Open Access Journals (Sweden)

    Renato Cicchetti

    2014-01-01

    Full Text Available An overview of the near-field-far-field (NF-FF transformation techniques with innovative spiral scannings, useful to derive the radiation patterns of the antennas commonly employed in the modern wireless communication systems, is provided in this paper. The theoretical background and the development of a unified theory of the spiral scannings for quasi-spherical and nonspherical antennas are described, and an optimal sampling interpolation expansion to evaluate the probe response on a quite arbitrary rotational surface from a nonredundant number of its samples, collected along a proper spiral wrapping it, is presented. This unified theory can be applied to spirals wrapping the conventional scanning surfaces and makes it possible to accurately reconstruct the NF data required by the NF-FF transformation employing the corresponding classical scanning. A remarkable reduction of the measurement time is so achieved, due to the use of continuous and synchronized movements of the positioning systems and to the reduced number of needed NF measurements. Some numerical and experimental results relevant to the spherical spiral scanning case when dealing with quasi-planar and electrically long antennas are shown.

  1. Intercomparison of two dynamic treatment techniques, ring scan and spot scan, for head and neck tumors with the Piotron

    International Nuclear Information System (INIS)

    Takai, M.; Blattmann, H.; Pedroni, E.

    1988-01-01

    An evaluation of the ring scan and the spot scan was made for the pion irradiation of head and neck tumors with the Piotron. For the geometry of the Piotron, with its 60 radially converging beams, two scanning techniques have been developed, ring scan and spot scan. They have different characteristics concerning achievable dose distributions and sensitivity to tissue inhomogenities. The optimized 3-dimensional dose distributions for the treatment with ring scan and spot scan techniques were calculated for two examples of the target volume. The comparison of the dose distributions has shown that the ring scan is better in sparing normal tissues than the spot scan for a simple shape target volume but not for an irregular shape target volume with the present status of the technique. The irradiation time needed for the ring scan is longer, for the present examples three times, than for the spot scan. From the practical view point the spot scan is preferable to the ring scan for the treatment of head and neck tumors with the Piotron

  2. Investigations of Differential Scanning Techniques using Two Radionuclides

    Energy Technology Data Exchange (ETDEWEB)

    Cottrall, M. F.; French, Rosemary J.; Trott, N. G. [Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey (United Kingdom)

    1969-01-15

    In the development of scanning procedures difficulties sometimes arise because a particular radiopharmaceutical, which is selectively concentrated in an organ of interest, is also widely distributed in neighbouring sites in the body. Investigations have been made of a method which involves the use of a second radioactive substance to label such sites. By means of suitable electrical circuits fitted to a conventional mechanical scanner (Picker Magnascanner III), a direct colour scan of the organ under study can be obtained. Signals from the two radionuclides are distinguished by pulse-height analysis and used to operate the colour shift mechanism. Experimental studies with phantoms and clinical trials are reported. An analysis of the statistical limitations of the technique is given, including a discussion of the most suitable operating conditions for particular pairs of radionuclides. Illustrations include the use of {sup 75}Se selenomethionine and {sup 99m}Tc sulphur colloid or {sup 198}Au colloid in the delineation of the pancreas, and reference is also made to work with {sup 18}F, {sup 99m}Tc, {sup 133m}In and {sup 197}Hg, which are used in various chemical forms to visualize specific types of tumours in vascular surroundings labelled with other suitable tracers. Some discussion of the dosimetry of these procedures is made, since the extent to which the technique can be applied may be limited by the activities which can be administered. However, successful results are being obtained using activities within the range generally accepted for single radionuclide scanning procedures. For example, the pancreas can be successfully visualised using 250 {mu}Ci {sup 75}Se selenomethionine in combination with 1 mCi {sup 99m}TC sulphur colloid. (author)

  3. 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...

  4. 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.

  5. 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.

  6. 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...

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  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. 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

  18. 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.

  19. 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].

  20. Nuclear reactor vessel surface inspecting technique applying electric resistance probe

    International Nuclear Information System (INIS)

    Yamaguchi, T.; Enami, K.; Yoshioka, M.

    1975-01-01

    A new technique for inspecting the inner surface of the PWR type nuclear reactor vessel by use of an electric resistance probe is introduced, centering on a data processing system. This system is composed of a mini-computer, a system typewriter, an interface unit, a D-A converter and controller, and X-Y recorder and others. Its functions are judging flaws and making flaw detection maps. In order to judge flaws by flaw detection signals, three kinds of flaw judging methods have been developed. In case there is a flaw, its position and depth are calculated and listed on the system typewriter. The flaw detection maps are expressed in four kinds of modes and they are displayed on the X-Y recorder. (auth.)

  1. 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.

  2. 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.

  3. Techniques for Pump-Probe Synchronisation of Fsec Radiation Pulses

    CERN Document Server

    Schlarb, Holger

    2005-01-01

    The increasing interest on the production of ultra-short photon pulses in future generations of Free-Electron Lasers operating in the UV, VUV or X-ray regime demands new techniques to reliably measure and control the arrival time of the FEL-pulses at the experiment. For pump-probe experiments using external optical lasers the desired synchronisation is in the order of tens of femtoseconds, the typical duration of the FEL pulse. Since, the accelerators are large scale facilities of the length of several hundred meters or even kilometers, the problem of synchronisation has to be attacked twofold. First, the RF acceleration sections upstream of the magnetic bunch compressors need to be stabilised in amplitude and phase to high precision. Second, the remain electron beam timing jitter needs to be determined with femtosecond accuracy for off-line analysis. In this talk, several techniques using the electron or the FEL beam to monitor the arrival time are presented, and the proposed layout of the synchronisation sy...

  4. Probe-based confocal laser endomicroscopy (pCLE) - a new imaging technique for in situ localization of spermatozoa.

    Science.gov (United States)

    Trottmann, Matthias; Stepp, Herbert; Sroka, Ronald; Heide, Michael; Liedl, Bernhard; Reese, Sven; Becker, Armin J; Stief, Christian G; Kölle, Sabine

    2015-05-01

    In azoospermic patients, spermatozoa are routinely obtained by testicular sperm extraction (TESE). However, success rates of this technique are moderate, because the site of excision of testicular tissue is determined arbitrarily. Therefore the aim of this study was to establish probe-based laser endomicroscopy (pCLE) a noval biomedical imaging technique, which provides the opportunity of non-invasive, real-time visualisation of tissue at histological resolution. Using pCLE we clearly visualized longitudinal and horizontal views of the tubuli seminiferi contorti and localized vital spermatozoa. Obtained images and real-time videos were subsequently compared with confocal laser scanning microscopy (CLSM) of spermatozoa and tissues, respectively. Comparative visualization of single native Confocal laser scanning microscopy (CLSM, left) and probe-based laser endomicroscopy (pCLE, right) using Pro Flex(TM) UltraMini O after staining with acriflavine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Scanning microwave microscopy technique for nanoscale characterization of magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, C.H., E-mail: hadlee.joseph@artov.imm.cnr.it [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Department of Electronics Engineering, University of Rome “Tor Vergata”, Via del Politecnico 1, 00133 Rome (Italy); Sardi, G.M. [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Tuca, S.S.; Gramse, G. [Johannes Kepler University, Institute for Biophysics, Gruberstrasse 40, A-4020 Linz (Austria); Lucibello, A.; Proietti, E. [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Kienberger, F. [Keysight Technologies Austria GmbH, Keysight Laboratories, Gruberstrasse 40, A-4020 Linz (Austria); Marcelli, R. [National Research Council, Institute for Microelectronics and Microsystems (CNR-IMM), Via del Fosso del Cavaliere 100, 00133 Rome (Italy)

    2016-12-15

    In this work, microwave characterization of magnetic materials using the scanning microwave microscopy (SMM) technique is presented. The capabilities of the SMM are employed for analyzing and imaging local magnetic properties of the materials under test at the nanoscale. The analyses are performed by acquiring both amplitude and phase of the reflected microwave signal. The changes in the reflection coefficient S{sub 11} are related to the local properties of the material under investigation, and the changes in its magnetic properties have been studied as a function of an external DC magnetic bias. Yttrium iron garnet (YIG) films deposited by RF sputtering and grown by liquid phase epitaxial (LPE) on gadolinium gallium garnet (GGG) substrates and permalloy samples have been characterized. An equivalent electromagnetic transmission line model is discussed for the quantitative analysis of the local magnetic properties. We also observed the hysteretic behavior of the reflection coefficient S{sub 11} with an external bias field. The imaging and spectroscopy analysis on the experimental results are evidently indicating the possibilities of measuring local changes in the intrinsic magnetic properties on the surface of the material.

  6. [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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Advantages of the first-derivative probe technique over the three- and four-parameter probe techniques in fusion plasmas diagnostics

    Czech Academy of Sciences Publication Activity Database

    Hasan, E.; Dimitrova, Miglena; Popov, T.; Ivanova, P.; Dejarnac, Renaud; Stöckel, Jan; Pánek, Radomír

    2018-01-01

    Roč. 13, č. 4 (2018), č. článku P04005. ISSN 1748-0221 R&D Projects: GA MŠk(CZ) LM2015045 Institutional support: RVO:61389021 Keywords : Plasma potential * electron temperature * bi-Maxwellian EEDF * Divertor Langmuir probes * three- and four-parameter probe techniques * first-derivative probe technique Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: 2.11 Other engineering and technologies Impact factor: 1.220, year: 2016 http://iopscience.iop.org/article/10.1088/1748-0221/13/04/P04005/meta

  7. Application of the planar-scanning technique to the near-field dosimetry of millimeter-wave radiators.

    Science.gov (United States)

    Zhao, Jianxun; Lu, Hongmin; Deng, Jun

    2015-02-01

    The planar-scanning technique was applied to the experimental measurement of the electric field and power flux density (PFD) in the exposure area close to the millimeter-wave (MMW) radiator. In the near-field region, the field and PFD were calculated from the plane-wave spectrum of the field sampled on a scan plane far from the radiator. The measurement resolution was improved by reducing the spatial interval between the field samples to a fraction of half the wavelength and implementing multiple iterations of the fast Fourier transform. With the reference to the results from the numerical calculation, an experimental evaluation of the planar-scanning measurement was made for a 50 GHz radiator. Placing the probe 1 to 3 wavelengths from the aperture of the radiator, the direct measurement gave the near-field data with significant differences from the numerical results. The planar-scanning measurement placed the probe 9 wavelengths away from the aperture and effectively reduced the maximum and averaged differences in the near-field data by 70.6% and 65.5%, respectively. Applied to the dosimetry of an open-ended waveguide and a choke ring antenna for 60 GHz exposure, the technique proved useful to the measurement of the PFD in the near-field exposure area of MMW radiators. © 2015 Wiley Periodicals, Inc.

  8. Circularly polarized light to study linear magneto-optics for ferrofluids: θ-scan technique

    Science.gov (United States)

    Meng, Xiangshen; Huang, Yan; He, Zhenghong; Lin, Yueqiang; Liu, Xiaodong; Li, Decai; Li, Jian; Qiu, Xiaoyan

    2018-06-01

    Circularly polarized light can be divided into two vertically linearly polarized light beams with  ±π/2 phase differences. In the presence of an external magnetic field, when circularly polarized light travels through a ferrofluid film, whose thickness is no more than that of λ/4 plate, magneto-optical, magnetic birefringence and dichroism effects cause the transmitted light to behave as elliptically polarized light. Using angular scan by a continuously rotating polarizer as analyzer, the angular (θ) distribution curve of relative intensity (T) corresponding to elliptically polarized light can be measured. From the T  ‑  θ curve having ellipsometry, the parameters such as the ratio of short to long axis, and angular orientation of the long axis to the vertical field direction can be obtained. Thus, magnetic birefringence and dichroism can be probed simultaneously by measuring magneto-optical, positive or negative birefringence and dichroism features from the transmission mode. The proposed method is called θ-scan technique, and can accurately determine sample stability, magnetic field direction, and cancel intrinsic light source ellipticity. This study may be helpful to further research done to ferrofluids and other similar colloidal samples with anisotropic optics.

  9. 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.

  10. 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

  11. 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...

  12. 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

  13. Differential scanning calorimetry techniques: applications in biology and nanoscience.

    Science.gov (United States)

    Gill, Pooria; Moghadam, Tahereh Tohidi; Ranjbar, Bijan

    2010-12-01

    This paper reviews the best-known differential scanning calorimetries (DSCs), such as conventional DSC, microelectromechanical systems-DSC, infrared-heated DSC, modulated-temperature DSC, gas flow-modulated DSC, parallel-nano DSC, pressure perturbation calorimetry, self-reference DSC, and high-performance DSC. Also, we describe here the most extensive applications of DSC in biology and nanoscience.

  14. Differential Scanning Calorimetry Techniques: Applications in Biology and Nanoscience

    OpenAIRE

    Gill, Pooria; Moghadam, Tahereh Tohidi; Ranjbar, Bijan

    2010-01-01

    This paper reviews the best-known differential scanning calorimetries (DSCs), such as conventional DSC, microelectromechanical systems-DSC, infrared-heated DSC, modulated-temperature DSC, gas flow-modulated DSC, parallel-nano DSC, pressure perturbation calorimetry, self-reference DSC, and high-performance DSC. Also, we describe here the most extensive applications of DSC in biology and nanoscience.

  15. 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.

  16. 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)

  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. 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

  19. Studies of impurity recycling by the collector probe technique

    International Nuclear Information System (INIS)

    Hildebrandt, D.; Grote, H.; Herrmann, A.; Laux, M.; Pech, P.; Reiner, H.D.; Wolff, H.

    1987-01-01

    In order to study recycling effects of the nonintrinsic impurity Li discharges with and without LiD-pellet injection were investigated. The observed maximum impurity level of Li in the SOL plasma of discharges without injection reaches less than 10% of that observed in discharges with injection. The measurements offer the possibility to distinguish between influxes from the wall and those which reach the collector probe via the core plasma. The time evolution, orientation and radial dependence of the impurity fluxes are characteristic features of their origin. The consideration of all these features facilitates a better understanding of collector probe measurements in the SOL-plasma. (orig.)

  20. 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)

  1. Development of in situ two-coil mutual inductance technique in a multifunctional scanning tunneling microscope.

    Science.gov (United States)

    Duan, Ming-Chao; Liu, Zhi-Long; Ge, Jian-Feng; Tang, Zhi-Jun; Wang, Guan-Yong; Wang, Zi-Xin; Guan, Dandan; Li, Yao-Yi; Qian, Dong; Liu, Canhua; Jia, Jin-Feng

    2017-07-01

    Superconducting thin films have been a focal point for intensive research efforts since their reduced dimension allows for a wide variety of quantum phenomena. Many of these films, fabricated in UHV chambers, are highly vulnerable to air exposure, making it difficult to measure intrinsic superconducting properties such as zero resistance and perfect diamagnetism with ex situ experimental techniques. Previously, we developed a multifunctional scanning tunneling microscope (MSTM) containing in situ four-point probe (4PP) electrical transport measurement capability in addition to the usual STM capabilities [Ge et al., Rev. Sci. Instrum. 86, 053903 (2015)]. Here we improve this MSTM via development of both transmission and reflection two-coil mutual inductance techniques for in situ measurement of the diamagnetic response of a superconductor. This addition does not alter the original STM and 4PP functions of the MSTM. We demonstrate the performance of the two-coil mutual inductance setup on a 10-nm-thick NbN thin film grown on a Nb-doped SrTiO 3 (111) substrate.

  2. Scanning tunneling microscopy - STM: history, principle, construction, and related techniques

    International Nuclear Information System (INIS)

    Ostadal, I.; Sobotik, P.

    1998-01-01

    The method of scanning tunneling microscopy (STM) is discussed. The principle of STM and some other related methods is highlighted, and spectroscopy using STM is dealt with. A brief summary is given of problems to be solved in microscope design, and the influence of these on the resolution obtained is presented. A comparison of STM with other methods used at present in the physics of thin films and surfaces confirms its irreplaceability

  3. Quality Assurance By Laser Scanning And Imaging Techniques

    Science.gov (United States)

    SchmalfuB, Harald J.; Schinner, Karl Ludwig

    1989-03-01

    Laser scanning systems are well established in the world of fast industrial in-process quality inspection systems. The materials inspected by laser scanning systems are e.g. "endless" sheets of steel, paper, textile, film or foils. The web width varies from 50 mm up to 5000 mm or more. The web speed depends strongly on the production process and can reach several hundred meters per minute. The continuous data flow in one of different channels of the optical receiving system exceeds ten Megapixels/sec. Therefore it is clear that the electronic evaluation system has to process these data streams in real time and no image storage is possible. But sometimes (e.g. first installation of the system, change of the defect classification) it would be very helpful to have the possibility for a visual look on the original, i.e. not processed sensor data. At first we show the principle set up of a standard laser scanning system. Then we will introduce a large image memory especially designed for the needs of high-speed inspection sensors. This image memory co-operates with the standard on-line evaluation electronics and provides therefore an easy comparison between processed and non-processed data. We will discuss the basic system structure and we will show the first industrial results.

  4. 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

  5. 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.

  6. A Testable Design Method for Memories by Boundary Scan Technique

    Directory of Open Access Journals (Sweden)

    Qiao Guo-Hui

    2016-01-01

    Full Text Available This paper presents a design for test the embedded flash in an object System-on-a-chip (SoC. The feature of the Flash TAP (Test Access Port complies with the IEEE std.1149.1, and it can select different scan chains and other control registers for other test. By the trade-off between the test time and the circuit area, an IST (In System Test circuit is designed in the SoC. Experiment results on the embedded memory have shown that the proposed method costs small testing timing by the use of IST.

  7. 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.

  8. Novel Technique for Quantitative Fast Scanning Calorimetry on Electrospun Fibers

    Science.gov (United States)

    Thomas, David; Govinna, Nelaka; Schick, Christoph; Cebe, Peggy

    Fast scanning chip calorimetry allows for the study of polymers which have rapid nucleation and/or crystallization kinetics, or degrade within their melting range. Heating rates used, up to 4000 K/s, allow studies of hetero and homogeneous nucleation at time scales inaccessible with conventional calorimeters, whose rates are typically alcohol (PVA) were chosen in the development of a new methodology to obtain quantitative fast scanning thermal data from electrospun nanofibers using a Flash DSC1. The structure of nanofibers requires special methods to load nanogram-sized samples onto a UFSC1 sensor. Fibers were directly spun onto TEM grids which provide a durable substrate to support bundles of nanofibers and possess excellent thermal conductivity allowing for a strong, repeatable signal and ensure good sample to sensor contact. As spun samples were held isothermally at temperatures ranging from Tg to Tm then heated at 2,000 K/s to assess as-spun crystallinity and cold crystallization behaviors. Above Tm the fibers break up into micro- and nano-droplets. On these samples, melt crystallization experiments were performed to study nucleation and crystallization of polymer confined to nanodroplet morphology. NSF DMR-1608125.

  9. Techniques for blade tip clearance measurements with capacitive probes

    Science.gov (United States)

    Steiner, Alexander

    2000-07-01

    This article presents a proven but advantageous concept for blade tip clearance evaluation in turbomachinery. The system is based on heavy duty probes and a high frequency (HF) and amplifying electronic unit followed by a signal processing unit. Measurements are taken under high temperature and other severe conditions such as ionization. Every single blade can be observed. The signals are digitally filtered and linearized in real time. The electronic set-up is highly integrated. Miniaturized versions of the electronic units exist. The small and robust units can be used in turbo engines in flight. With several probes at different angles in one radial plane further information is available. Shaft eccentricity or blade oscillations can be calculated.

  10. 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

  11. 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.

  12. 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.

  13. Surface inspection technique with an eddy current testing array probe

    International Nuclear Information System (INIS)

    Nishimizu, Akira; Endo, Hisashi; Tooma, Masahiro; Otani, Kenichi; Ouchi, Hirofumi; Yoshida, Isao; Nonaka, Yoshio

    2010-01-01

    An eddy current testing (ECT) system has been developed for inspecting weld surfaces of components in the reactor pressure vessel of nuclear plants. The system can be applied to curved surfaces with an ECT array probe, it can discriminate flaws from other signal factors by using a combination of arrayed coils signal-phase. The system is applied to a mock-up of core internal components and the signal discrimination using the signal-phase clearly separated flaw and noise signals. (author)

  14. 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

  15. 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.

  16. Gamma scan technique for detecting coupon inside the mother pipeline

    International Nuclear Information System (INIS)

    Rasif Mohd Zain; Roslan Yahya; Mohamad Rabaie Shari; Airwan Affandi Mahmood; Mior Ahmad Khusaini Adnan

    2012-01-01

    Many times a year natural gas transmission and distribution companies need to make new connections to pipelines to expand or modify their existing system through hot tapping procedure. This procedure involves the installation of a new pipeline connection while the pipeline remains in service, flowing natural gas under pressure. The hot tap procedure includes attaching a branch connection and valve on the outside of an operating pipeline, and then cutting out the pipe-line wall within the branch and removing the wall section, which is called object of coupon through the valve. During the hot tapping process a critical problems occurred when a coupon fell into the mother pipeline. To overcome this problem, a gamma-ray absorption technique was chosen whereby a mapping technique will be done to detect the coupon position. The technique is non-destructive as it applies Co-60 (5 mCi) as a radioisotope sealed source to emit gamma radiation and a NaI(Tl) scintillation as detector. The result provided a visible representation of density profile inside pipeline where the coupon location can be located. This paper provides the detail of the technique used and presents the result obtained. (author)

  17. 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.

  18. 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)

  19. Exploring miniature insect brains using micro-CT scanning techniques

    Science.gov (United States)

    Smith, Dylan B.; Bernhardt, Galina; Raine, Nigel E.; Abel, Richard L.; Sykes, Dan; Ahmed, Farah; Pedroso, Inti; Gill, Richard J.

    2016-01-01

    The capacity to explore soft tissue structures in detail is important in understanding animal physiology and how this determines features such as movement, behaviour and the impact of trauma on regular function. Here we use advances in micro-computed tomography (micro-CT) technology to explore the brain of an important insect pollinator and model organism, the bumblebee (Bombus terrestris). Here we present a method for accurate imaging and exploration of insect brains that keeps brain tissue free from trauma and in its natural stereo-geometry, and showcase our 3D reconstructions and analyses of 19 individual brains at high resolution. Development of this protocol allows relatively rapid and cost effective brain reconstructions, making it an accessible methodology to the wider scientific community. The protocol describes the necessary steps for sample preparation, tissue staining, micro-CT scanning and 3D reconstruction, followed by a method for image analysis using the freeware SPIERS. These image analysis methods describe how to virtually extract key composite structures from the insect brain, and we demonstrate the application and precision of this method by calculating structural volumes and investigating the allometric relationships between bumblebee brain structures. PMID:26908205

  20. 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.

  1. 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

  2. Nonlinear optical properties of natural laccaic acid dye studied using Z-scan technique

    CSIR Research Space (South Africa)

    Zongo, S

    2015-08-01

    Full Text Available . The experiments were performed by using single beam Z-scan technique at 532 nm with 10 ns, 10 Hz Nd:YAG laser pulses excitation. From the open-aperture Z-scan data, we derived that the laccaic dye samples exhibit strong two photon absorption (2PA). The nonlinear...

  3. SYSTEMATIC SCANNING ELECTRON MICROSCOPY TECHNIQUE FOR EVALUATING COMBINED BIOLOIGCAL/GRANULAR ACTIVATED CARBON TREATMENT PROCESSES

    Science.gov (United States)

    A systematic scanning election microscope analytical technique has been developed to examine granular activated carbon used a a medium for biomass attachment in liquid waste treatment. The procedure allows for the objective monitoring, comparing, and trouble shooting of combined ...

  4. Three-dimensional laser scanning technique to quantify aggregate and ballast shape properties

    CSIR Research Space (South Africa)

    Anochie-Boateng, Joseph

    2013-06-01

    Full Text Available methods towards a more accurate and automated techniques to quantify aggregate shape properties. This paper validates a new flakiness index equation using three-dimensional (3-D) laser scanning data of aggregate and ballast materials obtained from...

  5. 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....

  6. 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.

  7. Local thermal conductivity of polycrystalline AlN ceramics measured by scanning thermal microscopy and complementary scanning electron microscopy techniques

    International Nuclear Information System (INIS)

    Zhang Yue-Fei; Wang Li; Wei Bin; Ji Yuan; Han Xiao-Dong; Zhang Ze; Heiderhoff, R.; Geinzer, A. K.; Balk, L. J.

    2012-01-01

    The local thermal conductivity of polycrystalline aluminum nitride (AlN) ceramics is measured and imaged by using a scanning thermal microscope (SThM) and complementary scanning electron microscope (SEM) based techniques at room temperature. The quantitative thermal conductivity for the AlN sample is gained by using a SThM with a spatial resolution of sub-micrometer scale through using the 3ω method. A thermal conductivity of 308 W/m·K within grains corresponding to that of high-purity single crystal AlN is obtained. The slight differences in thermal conduction between the adjacent grains are found to result from crystallographic misorientations, as demonstrated in the electron backscattered diffraction. A much lower thermal conductivity at the grain boundary is due to impurities and defects enriched in these sites, as indicated by energy dispersive X-ray spectroscopy. (condensed matter: structural, mechanical, and thermal properties)

  8. All-optical optoacoustic microscopy based on probe beam deflection technique

    OpenAIRE

    Maswadi, Saher M.; Ibey, Bennett L.; Roth, Caleb C.; Tsyboulski, Dmitri A.; Beier, Hope T.; Glickman, Randolph D.; Oraevsky, Alexander A.

    2016-01-01

    Optoacoustic (OA) microscopy using an all-optical system based on the probe beam deflection technique (PBDT) for detection of laser-induced acoustic signals was investigated as an alternative to conventional piezoelectric transducers. PBDT provides a number of advantages for OA microscopy including (i) efficient coupling of laser excitation energy to the samples being imaged through the probing laser beam, (ii) undistorted coupling of acoustic waves to the detector without the need for separa...

  9. Probe beam deflection technique as acoustic emission directionality sensor with photoacoustic emission source.

    Science.gov (United States)

    Barnes, Ronald A; Maswadi, Saher; Glickman, Randolph; Shadaram, Mehdi

    2014-01-20

    The goal of this paper is to demonstrate the unique capability of measuring the vector or angular information of propagating acoustic waves using an optical sensor. Acoustic waves were generated using photoacoustic interaction and detected by the probe beam deflection technique. Experiments and simulations were performed to study the interaction of acoustic emissions with an optical sensor in a coupling medium. The simulated results predict the probe beam and wavefront interaction and produced simulated signals that are verified by experiment.

  10. 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...

  11. Development of techniques for fabrication of film probe sensor assembly

    International Nuclear Information System (INIS)

    Moorhead, A.J.

    1982-10-01

    Pulsed laser welding and brazing techniques were developed for fabrication of sensors designed to measure liquid film properties in out-of-reactor safety tests that simulate a loss-of-coolant accident in a pressurized-water nuclear reactor. These sensors were made possible by a unique ceramic-to-metal seal system based on a cermet insulator and a brazing filler metal, both developed at ORNL. This seal system was shown to resist steam to an exposure of at least 100 h at 700 0 C (1292 0 F) and to resist repetitive thermal transients of 300 0 C/s (540 0 F). Procedures were also developed for induction brazing the instrumentation cables to a stainless steel end cap and for laser welding this component to the brazed sensor body itself. Cable end seals and sensor bodies fabricated with these designs and techniques maintained excellent helium leaktightness ( -6 cm 3 /s) after 20 severe thermal shock tests from 500 0 C air into water at 80 0 C

  12. 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.

  13. Virtual planning of dental implant placement using CT double scan-technique - own experience

    International Nuclear Information System (INIS)

    Wojciechowski, W.; Urbanik, A.; Kownacki, P.; Kownacki, S.

    2007-01-01

    The correctness of CT performed with the use of a double-scan technique is the basis for achieving proper quality of 3D reconstructions of the maxilla or mandible and subsequent virtual planning of dental implant placement. The aim of this study was the presentation of the methodology of computed tomography scanning and own experience with the use of the double-scan technique. The study group included 26 individuals who underwent MDCT with a double-scan technique using a MDCT scanner SOMATOM Sensation (Siemens, Germany). The parameters of the examination: slice-collimation 10 x 0.75 mm, slice-thickness 0.75 mm. The first CT scan in the procedure was the scan of the patient wearing a radiological prosthesis and occlusal index, which was followed by a separate scan of the radiological prosthesis. These two CT scans were copied and transferred to PC with Procera Software program (Nobel Biocare, Sweden) where dental implant placement was virtually planned. In all 26 patients, precise three-dimensional reconstructions of the anatomical structure were obtained. In 11 patients, on the basis of the virtual planning, the implant placement was performed, 5 patients were referred to preparatory procedures, that is, restoration of the alveolar process, otolaryngological treatment of the maxillary sinuses. The remaining 10 patients did not qualify to the procedure because of unfavorable anatomical ideation's. Correct computed tomography with double-scan technique enables virtual planning of dental implant placement, on the basis of which the real procedure of implantation can be performed. (author)

  14. 3D quantification of soil structure and functioning based on PET and CT scanning techniques

    DEFF Research Database (Denmark)

    Garbout, Amin

    This thesis explores the potential of PET and CT scanning techniques to quantify and visualize soil structure, root development, and soil/plant interactions. At the investigated scale, these non-invasive and nondestructive techniques have some obvious advantages compared with most other techniques....... The processed measurements show some expected and a few unexpected effects (or lack of effects) on different characteristics of soil structure. The combination of CT and PET scanning in an air plant soil controller system revealed some very interesting research possibilities. Interactions between soil structure...

  15. 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).

  16. 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)

  17. 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

  18. Line-Scan Hyperspectral Imaging Techniques for Food Safety and Quality Applications

    Directory of Open Access Journals (Sweden)

    Jianwei Qin

    2017-01-01

    Full Text Available Hyperspectral imaging technologies in the food and agricultural area have been evolving rapidly over the past 15 years owing to tremendous interest from both academic and industrial fields. Line-scan hyperspectral imaging is a major method that has been intensively researched and developed using different physical principles (e.g., reflectance, transmittance, fluorescence, Raman, and spatially resolved spectroscopy and wavelength regions (e.g., visible (VIS, near infrared (NIR, and short-wavelength infrared (SWIR. Line-scan hyperspectral imaging systems are mainly developed and used for surface inspection of food and agricultural products using area or line light sources. Some of these systems can also be configured to conduct spatially resolved spectroscopy measurements for internal or subsurface food inspection using point light sources. This paper reviews line-scan hyperspectral imaging techniques, with introduction, demonstration, and summarization of existing and emerging techniques for food and agricultural applications. The main topics include related spectroscopy techniques, line-scan measurement methods, hardware components and systems, system calibration methods, and spectral and image analysis techniques. Applications in food safety and quality are also presented to reveal current practices and future trends of line-scan hyperspectral imaging techniques.

  19. Pump-probe differencing technique for cavity-enhanced, noise-canceling saturation laser spectroscopy.

    Science.gov (United States)

    de Vine, Glenn; McClelland, David E; Gray, Malcolm B; Close, John D

    2005-05-15

    We present an experimental technique that permits mechanical-noise-free, cavity-enhanced frequency measurements of an atomic transition and its hyperfine structure. We employ the 532-nm frequency-doubled output from a Nd:YAG laser and an iodine vapor cell. The cell is placed in a folded ring cavity (FRC) with counterpropagating pump and probe beams. The FRC is locked with the Pound-Drever-Hall technique. Mechanical noise is rejected by differencing the pump and probe signals. In addition, this differenced error signal provides a sensitive measure of differential nonlinearity within the FRC.

  20. An expert system for improving the gamma-ray scanning technique

    International Nuclear Information System (INIS)

    Laraki, K.; Alami, R.; Cherkaoui El Moursli, R.; Bensitel, A.; El Badri, L.

    2007-01-01

    The gamma-ray scanning technique is widely used in the diagnosis and identification of industrial installations, in general and, in particular, of distillation columns considered as the most critical components in petrochemical plants. It provides essential data to optimise the performance of columns and identify maintenance requirements. Due to the various difficulties that can arise while analysing a scanning profile and in order to benefit from the continuous advent of new technologies in the field of electronics and data processing, the team of the Division of Instrumentation and Industrial Applications of CNESTEN have conducted a project aiming the elaboration of an expert system for acquisition, processing and interpretation of the scanning results. This system consists of two main modules: the first one is devoted to the preparation and control of the scanning operation conditions, while the second module has been developed to carry out easily and effectively the automatic (on-line) analysis and interpretation of the scan profiles

  1. Errors in the calculation of sub-soil moisture probe by equivalent moisture content technique

    International Nuclear Information System (INIS)

    Lakshmipathy, A.V.; Gangadharan, P.

    1982-01-01

    The size of the soil sample required to obtain the saturation response, with a neutron moisture probe is quite large and this poses practical problems of handling and mixing large amounts of samples for absolute laboratory calibration. Hydrogenous materials are used as a substitute for water in the equivalent moisture content technique, for calibration of soil moisture probes. In this it is assumed that only hydrogen of the bulk sample is responsible for the slowing down of fast neutrons and the slow neutron countrate is correlated to equivalent water content by considering the hydrogen density of sample. It is observed that the higher atomic number elements present in water equivalent media also affect the response of the soil moisture probe. Hence calculations, as well as experiments, were undertaken to know the order of error introduced by this technique. The thermal and slow neutron flux distribution around the BF 3 counter of a sub-soil moisture probe is calculated using three group diffusion theory. The response of the probe corresponding to different equivalent moisture content of hydrogenous media, is calculated taking into consideration the effective length of BF 3 counter. Soil with hydrogenous media such as polyethylene, sugar and water are considered for calculation, to verify the suitability of these materials as substitute for water during calibration of soil moisture probe. Experiments were conducted, to verify the theoretically calculated values. (author)

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Parallel-scanning tomosynthesis using a slot scanning technique: Fixed-focus reconstruction and the resulting image quality

    International Nuclear Information System (INIS)

    Shibata, Koichi; Notohara, Daisuke; Sakai, Takihito

    2014-01-01

    Purpose: Parallel-scanning tomosynthesis (PS-TS) is a novel technique that fuses the slot scanning technique and the conventional tomosynthesis (TS) technique. This approach allows one to obtain long-view tomosynthesis images in addition to normally sized tomosynthesis images, even when using a system that has no linear tomographic scanning function. The reconstruction technique and an evaluation of the resulting image quality for PS-TS are described in this paper. Methods: The PS-TS image-reconstruction technique consists of several steps (1) the projection images are divided into strips, (2) the strips are stitched together to construct images corresponding to the reconstruction plane, (3) the stitched images are filtered, and (4) the filtered stitched images are back-projected. In the case of PS-TS using the fixed-focus reconstruction method (PS-TS-F), one set of stitched images is used for the reconstruction planes at all heights, thus avoiding the necessity of repeating steps (1)–(3). A physical evaluation of the image quality of PS-TS-F compared with that of the conventional linear TS was performed using a R/F table (Sonialvision safire, Shimadzu Corp., Kyoto, Japan). The tomographic plane with the best theoretical spatial resolution (the in-focus plane, IFP) was set at a height of 100 mm from the table top by adjusting the reconstruction program. First, the spatial frequency response was evaluated at heights of −100, −50, 0, 50, 100, and 150 mm from the IFP using the edge of a 0.3-mm-thick copper plate. Second, the spatial resolution at each height was visually evaluated using an x-ray test pattern (Model No. 38, PTW Freiburg, Germany). Third, the slice sensitivity at each height was evaluated via the wire method using a 0.1-mm-diameter tungsten wire. Phantom studies using a knee phantom and a whole-body phantom were also performed. Results: The spatial frequency response of PS-TS-F yielded the best results at the IFP and degraded slightly as the

  10. Parallel-scanning tomosynthesis using a slot scanning technique: fixed-focus reconstruction and the resulting image quality.

    Science.gov (United States)

    Shibata, Koichi; Notohara, Daisuke; Sakai, Takihito

    2014-11-01

    Parallel-scanning tomosynthesis (PS-TS) is a novel technique that fuses the slot scanning technique and the conventional tomosynthesis (TS) technique. This approach allows one to obtain long-view tomosynthesis images in addition to normally sized tomosynthesis images, even when using a system that has no linear tomographic scanning function. The reconstruction technique and an evaluation of the resulting image quality for PS-TS are described in this paper. The PS-TS image-reconstruction technique consists of several steps (1) the projection images are divided into strips, (2) the strips are stitched together to construct images corresponding to the reconstruction plane, (3) the stitched images are filtered, and (4) the filtered stitched images are back-projected. In the case of PS-TS using the fixed-focus reconstruction method (PS-TS-F), one set of stitched images is used for the reconstruction planes at all heights, thus avoiding the necessity of repeating steps (1)-(3). A physical evaluation of the image quality of PS-TS-F compared with that of the conventional linear TS was performed using a R/F table (Sonialvision safire, Shimadzu Corp., Kyoto, Japan). The tomographic plane with the best theoretical spatial resolution (the in-focus plane, IFP) was set at a height of 100 mm from the table top by adjusting the reconstruction program. First, the spatial frequency response was evaluated at heights of -100, -50, 0, 50, 100, and 150 mm from the IFP using the edge of a 0.3-mm-thick copper plate. Second, the spatial resolution at each height was visually evaluated using an x-ray test pattern (Model No. 38, PTW Freiburg, Germany). Third, the slice sensitivity at each height was evaluated via the wire method using a 0.1-mm-diameter tungsten wire. Phantom studies using a knee phantom and a whole-body phantom were also performed. The spatial frequency response of PS-TS-F yielded the best results at the IFP and degraded slightly as the distance from the IFP increased. A

  11. Parallel-scanning tomosynthesis using a slot scanning technique: Fixed-focus reconstruction and the resulting image quality

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Koichi, E-mail: shibatak@suzuka-u.ac.jp [Department of Radiological Technology, Faculty of Health Science, Suzuka University of Medical Science 1001-1, Kishioka-cho, Suzuka 510-0293 (Japan); Notohara, Daisuke; Sakai, Takihito [R and D Department, Medical Systems Division, Shimadzu Corporation 1, Nishinokyo-Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511 (Japan)

    2014-11-01

    Purpose: Parallel-scanning tomosynthesis (PS-TS) is a novel technique that fuses the slot scanning technique and the conventional tomosynthesis (TS) technique. This approach allows one to obtain long-view tomosynthesis images in addition to normally sized tomosynthesis images, even when using a system that has no linear tomographic scanning function. The reconstruction technique and an evaluation of the resulting image quality for PS-TS are described in this paper. Methods: The PS-TS image-reconstruction technique consists of several steps (1) the projection images are divided into strips, (2) the strips are stitched together to construct images corresponding to the reconstruction plane, (3) the stitched images are filtered, and (4) the filtered stitched images are back-projected. In the case of PS-TS using the fixed-focus reconstruction method (PS-TS-F), one set of stitched images is used for the reconstruction planes at all heights, thus avoiding the necessity of repeating steps (1)–(3). A physical evaluation of the image quality of PS-TS-F compared with that of the conventional linear TS was performed using a R/F table (Sonialvision safire, Shimadzu Corp., Kyoto, Japan). The tomographic plane with the best theoretical spatial resolution (the in-focus plane, IFP) was set at a height of 100 mm from the table top by adjusting the reconstruction program. First, the spatial frequency response was evaluated at heights of −100, −50, 0, 50, 100, and 150 mm from the IFP using the edge of a 0.3-mm-thick copper plate. Second, the spatial resolution at each height was visually evaluated using an x-ray test pattern (Model No. 38, PTW Freiburg, Germany). Third, the slice sensitivity at each height was evaluated via the wire method using a 0.1-mm-diameter tungsten wire. Phantom studies using a knee phantom and a whole-body phantom were also performed. Results: The spatial frequency response of PS-TS-F yielded the best results at the IFP and degraded slightly as the

  12. Improvements in technique for determining the surfactant penetration in hair fibres using scanning ion beam analyses

    International Nuclear Information System (INIS)

    Hollands, R.; Clough, A.S.; Meredith, P.

    1999-01-01

    The penetration abilities of surfactants need to be known by companies manufacturing hair-care products. In this work three complementary techniques were used simultaneously - PIXE, NRA and RBS - to measure the penetration of a surfactant, which had been deuterated, into permed hair fibres. Using a scanning micro-beam of 2 MeV 3 He ions 2-dimensional concentration maps were obtained which showed whether the surfactant penetrated the fibre or just stayed on the surface. This is the first report of the use of three simultaneous scattering techniques with a scanning micro-beam. (author)

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. Broadening the applications of the atom probe technique by ultraviolet femtosecond laser

    Energy Technology Data Exchange (ETDEWEB)

    Hono, K., E-mail: kazuhiro.hono@nims.go.jp [National Institute for Materials Science, Tsukuba 305-0047 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-0047 (Japan); CREST, Japan Science and Technology Agency (Japan); Ohkubo, T. [National Institute for Materials Science, Tsukuba 305-0047 (Japan); CREST, Japan Science and Technology Agency (Japan); Chen, Y.M.; Kodzuka, M. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-0047 (Japan); Oh-ishi, K. [National Institute for Materials Science, Tsukuba 305-0047 (Japan); CREST, Japan Science and Technology Agency (Japan); Sepehri-Amin, H. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-0047 (Japan); Li, F. [National Institute for Materials Science, Tsukuba 305-0047 (Japan); CREST, Japan Science and Technology Agency (Japan); Kinno, T. [Corporate R and D Center, Toshiba Corporation, Saiwai-ku, Kawasaki 212-8582 (Japan); CREST, Japan Science and Technology Agency (Japan); Tomiya, S.; Kanitani, Y. [Advanced Materials Laboratory, Sony Corporation, Atsugi, Kanagawa 243-0021 (Japan)

    2011-05-15

    Laser assisted field evaporation using ultraviolet (UV) wavelength gives rise to better mass resolution and signal-to-noise ratio in atom probe mass spectra of metals, semiconductors and insulators compared to infrared and green lasers. Combined with the site specific specimen preparation techniques using the lift-out and annular Ga ion milling in a focused ion beam machine, a wide variety of materials including insulating oxides can be quantitatively analyzed by the three-dimensional atom probe using UV laser assisted field evaporation. After discussing laser irradiation conditions for optimized atom probe analyses, recent atom probe tomography results on oxides, semiconductor devices and grain boundaries of sintered magnets are presented. -- Research highlights: {yields} Application of ultraviolet (UV) femtosecond pulsed laser in a three dimensional atom probe (3DAP). {yields} Improved mass resolution and signal-to-noise ratio in atom probe mass spectra using UV laser. {yields} UV laser facilitates 3DAP analysis of insulating oxides. {yields} Quantitative analysis of wide variety of materials including insulating oxides using UV femotosecond laser.

  18. Application of dual-energy scanning technique with dual-source CT in pulmonary mass lesions

    International Nuclear Information System (INIS)

    Jiang Jie; Xu Yiming; He Bo; Xie Xiaojie; Han Dan

    2012-01-01

    Objective: To explore the feasibility of DSCT dual-energy technique in pulmonary mass lesions. Methods: A total of 100 patients with pulmonary masses underwent conventional plain CT scan and dual-energy enhanced CT scan. The virtual non-contrast (VNC) images were obtained at post-processing workstation.The mean CT value,enhancement value,signal to noise ratio (SNR), image quality and radiation dose of pulmonary masses were compared between the two scan techniques using F or t test and the detectability of lesions was compared using Wilcoxon test. Results: There was no statistically significant difference among VNC (A) (32.89 ± 12.58) HU,VNC (S) (30.86 ± 9.60) HU and conventional plain images (35.89 ± 9.99) HU in mean CT value of mass (F =2.08, P>0.05). There was statistically significant difference among VNC (A) (3.29 ± 1.45), VNC (S) (3.93 ± 1.49) and conventional plain image (4.61 ± 1.50) in SNR (F =6.01, P<0.05), which of conventional plain scan was higher than that of VNC.The enhancement value of mass in conventional enhanced scan (60.74 ± 13.9) HU and distribution of iodine from VNC (A) (58.26 ± 31.99) HU was no statistically significant difference (t=0.48, P>0.05), but there was a significant difference between conventional enhanced scan (56.51 ± 17.94) HU and distribution of iodine from VNC (S) (52.65 ± 16.78) HU (t=4.45, P<0.05). There was no statistically significant difference among conventional plain scan (4.69 ± 0.06) and VNC (A) (4.60 ± 0.09), VNC (S) (4.61 ±0.11) in image quality at mediastinal window (F=3.014, P>0.05). The appearance, size, internal features of mass (such as necrosis, calcification and cavity) were showed the same in conventional plain scan, VNC (A) and VNC (S). Of 41 patients with hilar mass, 18 patients were found to have lobular and segmental perfusion decrease or defect. Perfusion defect area was found in 59 patients with peripheral lung mass. The radiation dose of dual-energy enhanced scan was lower than that of

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. Aperture Determination in the LHC Based on an Emittance Blowup Technique with Collimator Position Scan

    CERN Document Server

    Assmann, R W; del Carmen Alabau, M; Giovannozzi, M; Muller, GJ; Redaelli, S; Schmidt, F; Tomas, R; Wenninger, J; Wollmann, D

    2011-01-01

    A new method to determine the LHC aperture was proposed. The new component is a collimator scan technique that refers the globally measured aperture limit to the shadow of the primary collimator, expressed in sigmas of rms beam size. As a by-product the BLM response to beam loss is quantified. The method is described and LHC measurement results are presented.

  5. 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

  6. 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.

  7. Reliability of capturing foot parameters using digital scanning and the neutral suspension casting technique

    Science.gov (United States)

    2011-01-01

    Background A clinical study was conducted to determine the intra and inter-rater reliability of digital scanning and the neutral suspension casting technique to measure six foot parameters. The neutral suspension casting technique is a commonly utilised method for obtaining a negative impression of the foot prior to orthotic fabrication. Digital scanning offers an alternative to the traditional plaster of Paris techniques. Methods Twenty one healthy participants volunteered to take part in the study. Six casts and six digital scans were obtained from each participant by two raters of differing clinical experience. The foot parameters chosen for investigation were cast length (mm), forefoot width (mm), rearfoot width (mm), medial arch height (mm), lateral arch height (mm) and forefoot to rearfoot alignment (degrees). Intraclass correlation coefficients (ICC) with 95% confidence intervals (CI) were calculated to determine the intra and inter-rater reliability. Measurement error was assessed through the calculation of the standard error of the measurement (SEM) and smallest real difference (SRD). Results ICC values for all foot parameters using digital scanning ranged between 0.81-0.99 for both intra and inter-rater reliability. For neutral suspension casting technique inter-rater reliability values ranged from 0.57-0.99 and intra-rater reliability values ranging from 0.36-0.99 for rater 1 and 0.49-0.99 for rater 2. Conclusions The findings of this study indicate that digital scanning is a reliable technique, irrespective of clinical experience, with reduced measurement variability in all foot parameters investigated when compared to neutral suspension casting. PMID:21375757

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. A quantitative damage imaging technique based on enhanced CCRTM for composite plates using 2D scan

    Science.gov (United States)

    He, Jiaze; Yuan, Fuh-Gwo

    2016-10-01

    A two-dimensional (2D) non-contact areal scan system was developed to image and quantify impact damage in a composite plate using an enhanced zero-lag cross-correlation reverse-time migration (E-CCRTM) technique. The system comprises a single piezoelectric wafer mounted on the composite plate and a laser Doppler vibrometer (LDV) for scanning a region in the vicinity of the PZT to capture the scattered wavefield. The proposed damage imaging technique takes into account the amplitude, phase, geometric spreading, and all of the frequency content of the Lamb waves propagating in the plate; thus, a reflectivity coefficients of the delamination is calculated and potentially related to damage severity. Comparisons are made in terms of damage imaging quality between 2D areal scans and 1D line scans as well as between the proposed and existing imaging conditions. The experimental results show that the 2D E-CCRTM performs robustly when imaging and quantifying impact damage in large-scale composites using a single PZT actuator with a nearby areal scan using LDV.

  16. 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.

  17. Z-scan: A simple technique for determination of third-order optical nonlinearity

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vijender, E-mail: chahal-gju@rediffmail.com [Department of Applied Science, N.C. College of Engineering, Israna, Panipat-132107, Haryana (India); Aghamkar, Praveen, E-mail: p-aghamkar@yahoo.co.in [Department of Physics, Chaudhary Devi Lal University, Sirsa-125055, Haryana (India)

    2015-08-28

    Z-scan is a simple experimental technique to measure intensity dependent nonlinear susceptibilities of third-order nonlinear optical materials. This technique is used to measure the sign and magnitude of both real and imaginary part of the third order nonlinear susceptibility (χ{sup (3)}) of nonlinear optical materials. In this paper, we investigate third-order nonlinear optical properties of Ag-polymer composite film by using single beam z-scan technique with Q-switched, frequency doubled Nd: YAG laser (λ=532 nm) at 5 ns pulse. The values of nonlinear absorption coefficient (β), nonlinear refractive index (n{sub 2}) and third-order nonlinear optical susceptibility (χ{sup (3)}) of permethylazine were found to be 9.64 × 10{sup −7} cm/W, 8.55 × 10{sup −12} cm{sup 2}/W and 5.48 × 10{sup −10} esu, respectively.

  18. The role of model-based methods in the development of single scan techniques

    International Nuclear Information System (INIS)

    Laruelle, Marc

    2000-01-01

    Single scan techniques are highly desirable for clinical trials involving radiotracers because they increase logistical feasibility, improve patient compliance, and decrease the cost associated with the study. However, the information derived from single scans usually are biased by factors unrelated to the process of interest. Therefore, identification of these factors and evaluation of their impact on the proposed outcome measure is important. In this paper, the impact of confounding factors on single scan measurements is illustrated by discussing the effect of between-subject or between-condition differences in radiotracer plasma clearance on normalized activity ratios (specific to nonspecific ratios) in the tissue of interest. Computer simulation based on kinetic analyses are presented to demonstrate this effect. It is proposed that the presence of this and other confounding factors should not necessarily preclude clinical trials based on single scan techniques. First, knowledge of the distribution of plasma clearance values in a sample of the investigated population allows researchers to assign limits to this potential bias. This information can be integrated in the power analysis. Second, the impact of this problem will vary according to the characteristic of the radiotracer, and this information can be used in the development and selection of the radiotracer. Third, simple modification of the experimental design (such as administration of the radiotracer as a bolus, followed by constant infusion, rather than as a single bolus) might remove this potential confounding factor and allow appropriate quantification within the limits of a single scanning session. In conclusion, model-based kinetic characterization of radiotracer distribution and uptake is critical to the design and interpretation of clinical trials based on single scan techniques

  19. Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Matthew W. [Iowa State Univ., Ames, IA (United States)

    2013-01-01

    This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

  20. 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.

  1. 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.

  2. 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.

  3. 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).

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. Two-dimensional in situ metrology of X-ray mirrors using the speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Laundy, David; Sawhney, Kawal [Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom)

    2015-06-06

    The two-dimensional slope error of an X-ray mirror has been retrieved by employing the speckle scanning technique, which will be valuable at synchrotron radiation facilities and in astronomical telescopes. In situ metrology overcomes many of the limitations of existing metrology techniques and is capable of exceeding the performance of present-day optics. A novel technique for precisely characterizing an X-ray bimorph mirror and deducing its two-dimensional (2D) slope error map is presented. This technique has also been used to perform fast optimization of a bimorph mirror using the derived 2D piezo response functions. The measured focused beam size was significantly reduced after the optimization, and the slope error map was then verified by using geometrical optics to simulate the focused beam profile. This proposed technique is expected to be valuable for in situ metrology of X-ray mirrors at synchrotron radiation facilities and in astronomical telescopes.

  9. 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.

  10. A study of trapped ion dynamics by photon-correlation and pulse-probe techniques

    International Nuclear Information System (INIS)

    Rink, J.; Dholakia, K.; Zs, G.; Horvath, K.; Hernandez-Pozos, J. L.; Power, W.; Segal, D. M.; Thompson, R. C.; Walker, T.

    1995-01-01

    We demonstrate non-evasive methods for observing ion and ion cloud oscillation frequencies in a quadrupole ion trap. These trap resonances are measured for small clouds using a photon correlation technique. For large clouds the rotation frequency can be detected with the help of an additional pulsed probe laser. We show applications of the photon correlation method such as estimating the dynamic properties of a combined trap and detecting ion crystals

  11. Measurement of mesothelioma on thoracic CT scans: A comparison of manual and computer-assisted techniques

    International Nuclear Information System (INIS)

    Armato, Samuel G. III; Oxnard, Geoffrey R.; MacMahon, Heber; Vogelzang, Nicholas J.; Kindler, Hedy L.; Kocherginsky, Masha; Starkey, Adam

    2004-01-01

    Our purpose in this study was to evaluate the variability of manual mesothelioma tumor thickness measurements in computed tomography (CT) scans and to assess the relative performance of six computerized measurement algorithms. The CT scans of 22 patients with malignant pleural mesothelioma were collected. In each scan, an initial observer identified up to three sites in each of three CT sections at which tumor thickness measurements were to be made. At each site, five observers manually measured tumor thickness through a computer interface. Three observers repeated these measurements during three separate sessions. Inter- and intra-observer variability in the manual measurement of tumor thickness was assessed. Six automated measurement algorithms were developed based on the geometric relationship between a specified measurement site and the automatically extracted lung regions. Computer-generated measurements were compared with manual measurements. The tumor thickness measurements of different observers were highly correlated (r≥0.99); however, the 95% limits of agreement for relative inter-observer difference spanned a range of 30%. Tumor thickness measurements generated by the computer algorithms also correlated highly with the average of observer measurements (r≥0.93). We have developed computerized techniques for the measurement of mesothelioma tumor thickness in CT scans. These techniques achieved varying levels of agreement with measurements made by human observers

  12. Single- and multi-frequency detection of surface displacements via scanning probe microscopy.

    Science.gov (United States)

    Romanyuk, Konstantin; Luchkin, Sergey Yu; Ivanov, Maxim; Kalinin, Arseny; Kholkin, Andrei L

    2015-02-01

    Piezoresponse force microscopy (PFM) provides a novel opportunity to detect picometer-level displacements induced by an electric field applied through a conducting tip of an atomic force microscope (AFM). Recently, it was discovered that superb vertical sensitivity provided by PFM is high enough to monitor electric-field-induced ionic displacements in solids, the technique being referred to as electrochemical strain microscopy (ESM). ESM has been implemented only in multi-frequency detection modes such as dual AC resonance tracking (DART) and band excitation, where the response is recorded within a finite frequency range, typically around the first contact resonance. In this paper, we analyze and compare signal-to-noise ratios of the conventional single-frequency method with multi-frequency regimes of measuring surface displacements. Single-frequency detection ESM is demonstrated using a commercial AFM.

  13. Density, temperature, and potential fluctuation measurements by the swept Langmuir probe technique in Wendelstein 7-AS

    International Nuclear Information System (INIS)

    Giannone, L.; Balbin, R.; Niedermeyer, H.; Endler, M.; Herre, G.; Hidalgo, C.; Rudyj, A.; Theimer, G.; Verplanke, P.

    1994-01-01

    In the Wendelstein 7-AS stellarator (W7-AS) [Plasma Phys. Controlled Fusion 33, 1591 (1991)], current-voltage characteristics of the Langmuir probe at sweep frequencies in the range 400 kHz to 1 MHz were measured and it was found that the mean and fluctuation values of the ion saturation current, floating potential, and electron temperature were independent of the sweep frequency. A radial scan in the vicinity of the velocity shear layer was performed. The simultaneous sweeping of 3 probe tips showed a statistically significant spatial coherence of the fluctuations in the poloidal direction and a decrease in spatial coherence of the fluctuations with increasing tip separation could be demonstrated. The observation of a change in the propagation direction of fluctuations as the shear layer was crossed and a calculation of the transport spectrum show that the swept probe method is capable of reproducing known results. Apparent temperature fluctuations, due to variations of density and potential during a sweep, are shown by simulations to be only of importance at frequencies above half the Nyquist frequency

  14. Combined amplification and hybridization techniques for genome scanning in vegetatively propagated crops

    Energy Technology Data Exchange (ETDEWEB)

    Kahl, G; Ramser, J; Terauchi, R [Biocentre, University of Frankfurt, Frankfurt am Main (Germany); Lopez-Peralta, C [IRGP, Colegio de Postgraduados, Montecillo, Edo. de Mexico, Texcoco (Mexico); Asemota, H N [Biotechnology Centre, University of the West Indies, Mona, Kingston (Jamaica); Weising, K [School of Biological Sciences, University of Auckland, Auckland (New Zealand)

    1998-10-01

    A combination of PCR- and hybridization-based genome scanning techniques and sequence comparisons between non-coding chloroplast DNA flanking tRNA genes has been employed to screen Dioscorea species for intra- and interspecific genetic diversity. This methodology detected extensive polymorphisms within Dioscorea bulbifera L., and revealed taxonomic and phylogenetic relationships among cultivated Guinea yams varieties and their potential wild progenitors. Finally, screening of yam germplasm grown in Jamaica permitted reliable discrimination between all major cultivars. Genome scanning by micro satellite-primed PCR (MP-PCR) and random amplified polymorphic DNA (RAPD) analysis in combination with the novel random amplified micro satellite polymorphisms (RAMPO) hybridization technique has shown high potential for the genetic analysis of yams, and holds promise for other vegetatively propagated orphan crops. (author) 46 refs, 3 figs, 3 tabs

  15. Combined amplification and hybridization techniques for genome scanning in vegetatively propagated crops

    International Nuclear Information System (INIS)

    Kahl, G.; Ramser, J.; Terauchi, R.; Lopez-Peralta, C.; Asemota, H.N.; Weising, K.

    1998-01-01

    A combination of PCR- and hybridization-based genome scanning techniques and sequence comparisons between non-coding chloroplast DNA flanking tRNA genes has been employed to screen Dioscorea species for intra- and interspecific genetic diversity. This methodology detected extensive polymorphisms within Dioscorea bulbifera L., and revealed taxonomic and phylogenetic relationships among cultivated Guinea yams varieties and their potential wild progenitors. Finally, screening of yam germplasm grown in Jamaica permitted reliable discrimination between all major cultivars. Genome scanning by micro satellite-primed PCR (MP-PCR) and random amplified polymorphic DNA (RAPD) analysis in combination with the novel random amplified micro satellite polymorphisms (RAMPO) hybridization technique has shown high potential for the genetic analysis of yams, and holds promise for other vegetatively propagated orphan crops. (author)

  16. Development of scan analysis techniques employing a small computer. Progress report, August 1, 1974--July 31, 1975

    International Nuclear Information System (INIS)

    Kuhl, D.E.

    1975-01-01

    Progress is reported in the development of equipment and counting techniques for transverse section scanning of the brain following the administration of radiopharmaceuticals to evaluate regional blood flow. The scanning instrument has an array of 32 scintillation detectors that surround the head and scan data are analyzed using a small computer. (U.S.)

  17. Study on CT scanning technique of inferior horn of lateral ventricle

    International Nuclear Information System (INIS)

    Kakoi, Iwao; Okubo, Mitsuo; Nakamura, Sumio; Yoshinaga, Toshihiko; Shimono, Tetsuo

    1984-01-01

    It is said that temporal lobe epilepsy (TLE), one of the incurable epilepsies, results from the lesions of various structrues located in the medial and deep portion of the temporal lobe such as the hippocampus and amygdaloid nucleus. Routine CT scanning techniques cannot adequately delineate these structures in the assessment of TLE. The anatomical relationship between these medial temporal structures and the inferior horn of lateral ventricle which is lateral to them and easily identified by CT lead us to believe that the sections through the longitudinal plane of the inferior horn may clearly delineate them. The present experimental study was undertaken to develop the CT scan technique of the inferior horn of lateral ventricle, which results in the clear delineation of the region of the hippocampus and amygdaloid nucleus. As a result, A total of the 3-4 reversed axial 5 mm-thick section centered at 2.5 cm cephalad to the roof of the external auditory canal at a reversed 25 0 angle to ABL are adequate to delineate the inferior horn and the medial temporal structures. This scan technique is considered to be useful in the assessment of TLE. (author)

  18. Sensitivity studies on the multi-sensor conductivity probe measurement technique for two-phase flows

    Energy Technology Data Exchange (ETDEWEB)

    Worosz, Ted [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Bernard, Matt [The United States Nuclear Regulatory Commission, 11545 Rockville Pike, Rockville, MD 20852 (United States); Kong, Ran; Toptan, Aysenur [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Kim, Seungjin, E-mail: skim@psu.edu [Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, 230 Reber Building, University Park, PA 16802 (United States); Hoxie, Chris [The United States Nuclear Regulatory Commission, 11545 Rockville Pike, Rockville, MD 20852 (United States)

    2016-12-15

    Highlights: • Revised conductivity probe circuit to eliminate signal “ghosting” among sensors. • Higher sampling frequencies suggested for bubble number frequency and a{sub i} measurements. • Two-phase parameter sensitivity to measurement duration and bubble number investigated. • Sensors parallel to pipe wall recommended for symmetric bubble velocity measurements. • Sensor separation distance ratio (s/d) greater than four minimizes bubble velocity error. - Abstract: The objective of this study is to advance the local multi-sensor conductivity probe measurement technique through systematic investigation into several practical aspects of a conductivity probe measurement system. Firstly, signal “ghosting” among probe sensors is found to cause artificially high bubble velocity measurements and low interfacial area concentration (a{sub i}) measurements that depend on sampling frequency and sensor impedance. A revised electrical circuit is suggested to eliminate this artificial variability. Secondly, the sensitivity of the probe measurements to sampling frequency is investigated in 13 two-phase flow conditions with superficial liquid and gas velocities ranging from 1.00–5.00 m/s and 0.17–2.0 m/s, respectively. With increasing gas flow rate, higher sampling frequencies, greater than 100 kHz in some cases, are required to adequately capture the bubble number frequency and a{sub i} measurements. This trend is due to the increase in gas velocity and the transition to the slug flow regime. Thirdly, the sensitivity of the probe measurements to the measurement duration as well as the sample number is investigated for the same flow conditions. Measurements of both group-I (spherical/distorted) and group-II (cap/slug/churn-turbulent) bubbles are found to be relatively insensitive to both the measurement duration and the number of bubbles, as long as the measurements are made for a duration long enough to capture a collection of samples characteristic to a

  19. Profiling water content in soils with TDR: Comparison with the neutron probe technique

    International Nuclear Information System (INIS)

    Laurent, J.P.

    2000-01-01

    In November 1996, at a site on the Grenoble campus a 1.2-m-long neutron access tube, a 0.8-m fibreglass Trime access tube and three sets of 1-m twin-rod TDR probes were installed. Weekly measurements were made over a 9-month period. In addition, soil samples were taken from time to time with an auger, to determine gravimetric water-contents. The soil bulk density profile was initially characterised by gammametry using a Campbell TM probe. A Troxler TM 4300 was used for the neutron-probe measurements. The TDR signals, for further processing by TDR-SSI, were logged using a Trase 2000 from Soil Moisture Equipment Corporation TM . TDR methods were employed without any special calibration of the permittivity/water-content relationship: standard internal calibrations of the devices or Topp polynomial relation were always applied. The results of all these water-content profiling methods were compared in three ways: (i) the water-content profiles were plotted directly on the same graph for different dates; (ii) all the water contents measured at all dates and all depths were plotted against a corresponding 'reference', namely neutron probe or gravimetry; (iii) water balances were calculated for each method and their respective time-profiles analysed. There was fairly good agreement among the three profiling methods, indicating that TDR is now a viable alternative to nuclear techniques for soil water-content profiling. (author)

  20. Contribution of brain imaging techniques: CT-scan and magnetic resonance imaging (MRI)

    International Nuclear Information System (INIS)

    Pasco-Papon, A.; Gourdier, A.L.; Papon, X.; Caron-Poitreau, C.

    1996-01-01

    In light of the current lack of consensus on the benefit of carotid artery surgery to treat asymptomatic carotid artery stenosis, the decision to operate on a patient depends on individual evaluation and characterization of risk factors on carotid artery stenosis greater than 70 %. The assessment of such risk factors is based especially on non-invasive brain imaging techniques.Computed tomography scanning (CT-scan) and magnetic resonance imaging (MRI) enable two types of stenosis to be differentiated, i.e. stenoses which are symptomatic and those that are radiologically proven versus those which are clinically and radiologically silent. CT-scan investigation (with and without injection of iodinated contrast media) still continues to be a common routine test in 1996 whenever a surgical revascularization procedure is planned. The presence of deep lacunar infarcts ipsilateral to the carotid artery stenosis generally evidence the reality of stenosis and thus are useful to the surgeon in establishing whether surgery is indicated. In the absence a consensus on indications for surgical management, the surgeon could use the CT-scan and MRI as medicolegal records which could be compared to a subsequent postoperative CT-scan in case of ischemic complications associated with the surgical procedure. Furthermore, recent cerebral ischemia as evidenced by filling with contrast material, will call for postponing treatment by a few weeks. Although conventional MRI is more contributive than brain CT-scan in terms of sensibility and specificity, its indications are narrower because of its limited availability and cost constraints. But, development of angio-MRI and functional imaging promise that its future is assured and even perhaps as the sole diagnostic method if its indications are expanded to include preoperative angiographic evaluation of atheromatous lesions of supra-aortic trunks. (authors). 37 refs

  1. Characterization of ultrashort laser pulses employing self-phase modulation dispersion-scan technique

    Science.gov (United States)

    Sharba, A. B.; Chekhlov, O.; Wyatt, A. S.; Pattathil, R.; Borghesi, M.; Sarri, G.

    2018-03-01

    We present a new phase characterization technique for ultrashort laser pulses that employs self-phase modulation (SPM) in the dispersion scan approach. The method can be implemented by recording a set of nonlinearly modulated spectra generated with a set of known chirp values. The unknown phase of the pulse is retrieved by linking the recorded spectra to the initial spectrum of the pulse via a phase function guessed by a function minimization iterative algorithm. This technique has many advantages over the dispersion scan techniques that use frequency conversion processes. Mainly, the use of SPM cancels out the phase and group velocity mismatch errors and dramatically widens the spectral acceptance of the nonlinear medium and the range of working wavelength. The robustness of the technique is demonstrated with smooth and complex phase retrievals using numerical examples. The method is shown to be not affected by the spatial distribution of the beam or the presence of nonlinear absorption process. In addition, we present an efficient method for phase representation based on a summation of a set of Gaussian functions. The independence of the functions from each other prevents phase coupling of any kind and facilitates a flexible phase representation.

  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. The validation of the Z-Scan technique for the determination of plasma glucose

    Science.gov (United States)

    Alves, Sarah I.; Silva, Elaine A. O.; Costa, Simone S.; Sonego, Denise R. N.; Hallack, Maira L.; Coppini, Ornela L.; Rowies, Fernanda; Azzalis, Ligia A.; Junqueira, Virginia B. C.; Pereira, Edimar C.; Rocha, Katya C.; Fonseca, Fernando L. A.

    2013-11-01

    Glucose is the main energy source for the human body. The concentration of blood glucose is regulated by several hormones including both antagonists: insulin and glucagon. The quantification of glucose in the blood is used for diagnosing metabolic disorders of carbohydrates, such as diabetes, idiopathic hypoglycemia and pancreatic diseases. Currently, the methodology used for this determination is the enzymatic colorimetric with spectrophotometric. This study aimed to validate the use of measurements of nonlinear optical properties of plasma glucose via the Z-Scan technique. For this we used samples of calibrator patterns that simulate commercial samples of patients (ELITech ©). Besides calibrators, serum glucose levels within acceptable reference values (normal control serum - Brazilian Society of Clinical Pathology and Laboratory Medicine) and also overestimated (pathological control serum - Brazilian Society of Clinical Pathology and Laboratory Medicine) were used in the methodology proposal. Calibrator dilutions were performed and determined by the Z-Scan technique for the preparation of calibration curve. In conclusion, Z-Scan method can be used to determinate glucose levels in biological samples with enzymatic colorimetric reaction and also to apply the same quality control parameters used in biochemistry clinical.

  4. Ultrasonic C-scan Technique for Nondestructive Evaluation of Spot Weld Quality

    International Nuclear Information System (INIS)

    Park, Ik Gun

    1994-01-01

    This paper discusses the feasibility of ultrasonic C-scan technique for nondestructive evaluation of spot weld quality. Ultrasonic evaluation for spot weld quality was performed by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of the corona bond from nugget, preliminary infinitesimal gap experiment by newton ring is tried in order to set up the optimum ultrasonic test condition. Ultrasonic image data obtained were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be measured with the accuracy of 1.0mm, and voids included in nugget can be detected to 10μm extent with simplicity and accuracy. Finally, it was found that it is necessary to make a profound study of definite discrimination of corona bond from nugget and the approach of quantitative evaluation of nugget diameter by utilizing the various image processing techniques

  5. Metabolomic Fingerprints of Individual Algal Cells Using the Single-Probe Mass Spectrometry Technique

    Directory of Open Access Journals (Sweden)

    Mei Sun

    2018-04-01

    Full Text Available Traditional approaches for the assessment of physiological responses of microbes in the environment rely on bulk filtration techniques that obscure differences among populations as well as among individual cells. Here, were report on the development on a novel micro-scale sampling device, referred to as the “Single-probe,” which allows direct extraction of metabolites from living, individual phytoplankton cells for mass spectrometry (MS analysis. The Single-probe is composed of dual-bore quartz tubing which is pulled using a laser pipette puller and fused to a silica capillary and a nano-ESI. For this study, we applied Single-probe MS technology to the marine dinoflagellate Scrippsiella trochoidea, assaying cells grown under different illumination levels and under nitrogen (N limiting conditions as a proof of concept for the technology. In both experiments, significant differences in the cellular metabolome of individual cells could readily be identified, though the vast majority of detected metabolites could not be assigned to KEGG pathways. Using the same approach, significant changes in cellular lipid complements were observed, with individual lipids being both up- and down-regulated under light vs. dark conditions. Conversely, lipid content increased across the board under N limitation, consistent with an adjustment of Redfield stoichiometry to reflect higher C:N and C:P ratios. Overall, these data suggest that the Single-probe MS technique has the potential to allow for near in situ metabolomic analysis of individual phytoplankton cells, opening the door to targeted analyses that minimize cell manipulation and sampling artifacts, while preserving metabolic variability at the cellular level.

  6. Quantitative X-ray dark-field and phase tomography using single directional speckle scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hongchang, E-mail: hongchang.wang@diamond.ac.uk; Kashyap, Yogesh; Sawhney, Kawal [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)

    2016-03-21

    X-ray dark-field contrast tomography can provide important supplementary information inside a sample to the conventional absorption tomography. Recently, the X-ray speckle based technique has been proposed to provide qualitative two-dimensional dark-field imaging with a simple experimental arrangement. In this letter, we deduce a relationship between the second moment of scattering angle distribution and cross-correlation degradation of speckle and establish a quantitative basis of X-ray dark-field tomography using single directional speckle scanning technique. In addition, the phase contrast images can be simultaneously retrieved permitting tomographic reconstruction, which yields enhanced contrast in weakly absorbing materials. Such complementary tomography technique can allow systematic investigation of complex samples containing both soft and hard materials.

  7. 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

  8. 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).

  9. 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.

  10. New Technique for Fabrication of Scanning Single-Electron Transistor Microscopy Tips

    Science.gov (United States)

    Goodwin, Eric; Tessmer, Stuart

    Fabrication of glass tips for Scanning Single-Electron Transistor Microscopy (SSETM) can be expensive, time consuming, and inconsistent. Various techniques have been tried, with varying levels of success in regards to cost and reproducibility. The main requirement for SSETM tips is to have a sharp tip ending in a micron-scale flat face to allow for deposition of a quantum dot. Drawing inspiration from methods used to create tips from optical fibers for Near-Field Scanning Optical Microscopes, our group has come up with a quick and cost effective process for creating SSETM tips. By utilizing hydrofluoric acid to etch the tips and oleic acid to guide the etch profile, optical fiber tips with appropriate shaping can be rapidly prepared. Once etched, electric leads are thermally evaporated onto each side of the tip, while an aluminum quantum dot is evaporated onto the face. Preliminary results using various metals, oxide layers, and lead thicknesses have proven promising.

  11. VLBI FOR GRAVITY PROBE B. IV. A NEW ASTROMETRIC ANALYSIS TECHNIQUE AND A COMPARISON WITH RESULTS FROM OTHER TECHNIQUES

    International Nuclear Information System (INIS)

    Lebach, D. E.; Ratner, M. I.; Shapiro, I. I.; Bartel, N.; Bietenholz, M. F.; Lederman, J. I.; Ransom, R. R.; Campbell, R. M.; Gordon, D.; Lestrade, J.-F.

    2012-01-01

    When very long baseline interferometry (VLBI) observations are used to determine the position or motion of a radio source relative to reference sources nearby on the sky, the astrometric information is usually obtained via (1) phase-referenced maps or (2) parametric model fits to measured fringe phases or multiband delays. In this paper, we describe a 'merged' analysis technique which combines some of the most important advantages of these other two approaches. In particular, our merged technique combines the superior model-correction capabilities of parametric model fits with the ability of phase-referenced maps to yield astrometric measurements of sources that are too weak to be used in parametric model fits. We compare the results from this merged technique with the results from phase-referenced maps and from parametric model fits in the analysis of astrometric VLBI observations of the radio-bright star IM Pegasi (HR 8703) and the radio source B2252+172 nearby on the sky. In these studies we use central-core components of radio sources 3C 454.3 and B2250+194 as our positional references. We obtain astrometric results for IM Peg with our merged technique even when the source is too weak to be used in parametric model fits, and we find that our merged technique yields astrometric results superior to the phase-referenced mapping technique. We used our merged technique to estimate the proper motion and other astrometric parameters of IM Peg in support of the NASA/Stanford Gravity Probe B mission.

  12. Development of a technique for level measurement in pressure vessels using thermal probes and artificial neural networks

    International Nuclear Information System (INIS)

    Torres, Walmir Maximo

    2008-01-01

    A technique for level measurement in pressure vessels was developed using thermal probes with internal cooling and artificial neural networks (ANN's). This new concept of thermal probes was experimentally tested in an experimental facility (BETSNI) with two test sections, ST1 and ST2. Two different thermal probes were designed and constructed: concentric tubes probe and U tube probe. A data acquisition system (DAS) was assembled to record the experimental data during the tests. Steady state and transient level tests were carried out and the experimental data obtained were used as learning and recall data sets in the ANN's program RETRO-05 that simulate a multilayer perceptron with backpropagation. The results of the analysis show that the technique can be applied for level measurements in pressure vessel. The technique is applied for a less input temperature data than the initially designed to the probes. The technique is robust and can be used in case of lack of some temperature data. Experimental data available in literature from electrically heated thermal probe were also used in the ANN's analysis producing good results. The results of the ANN's analysis show that the technique can be improved and applied to level measurements in pressure vessels. (author)

  13. Comparison of intraoral scanning and conventional impression techniques using 3-dimensional superimposition.

    Science.gov (United States)

    Rhee, Ye-Kyu; Huh, Yoon-Hyuk; Cho, Lee-Ra; Park, Chan-Jin

    2015-12-01

    The aim of this study is to evaluate the appropriate impression technique by analyzing the superimposition of 3D digital model for evaluating accuracy of conventional impression technique and digital impression. Twenty-four patients who had no periodontitis or temporomandibular joint disease were selected for analysis. As a reference model, digital impressions with a digital impression system were performed. As a test models, for conventional impression dual-arch and full-arch, impression techniques utilizing addition type polyvinylsiloxane for fabrication of cast were applied. 3D laser scanner is used for scanning the cast. Each 3 pairs for 25 STL datasets were imported into the inspection software. The three-dimensional differences were illustrated in a color-coded map. For three-dimensional quantitative analysis, 4 specified contact locations(buccal and lingual cusps of second premolar and molar) were established. For twodimensional quantitative analysis, the sectioning from buccal cusp to lingual cusp of second premolar and molar were acquired depending on the tooth axis. In color-coded map, the biggest difference between intraoral scanning and dual-arch impression was seen (Pimpression and the smallest difference was seen between dual-arch and full-arch impression. The two- and three-dimensional deviations between intraoral scanner and dual-arch impression was bigger than full-arch and dual-arch impression (P.05).

  14. Comparison of intraoral scanning and conventional impression techniques using 3-dimensional superimposition

    Science.gov (United States)

    Rhee, Ye-Kyu

    2015-01-01

    PURPOSE The aim of this study is to evaluate the appropriate impression technique by analyzing the superimposition of 3D digital model for evaluating accuracy of conventional impression technique and digital impression. MATERIALS AND METHODS Twenty-four patients who had no periodontitis or temporomandibular joint disease were selected for analysis. As a reference model, digital impressions with a digital impression system were performed. As a test models, for conventional impression dual-arch and full-arch, impression techniques utilizing addition type polyvinylsiloxane for fabrication of cast were applied. 3D laser scanner is used for scanning the cast. Each 3 pairs for 25 STL datasets were imported into the inspection software. The three-dimensional differences were illustrated in a color-coded map. For three-dimensional quantitative analysis, 4 specified contact locations(buccal and lingual cusps of second premolar and molar) were established. For twodimensional quantitative analysis, the sectioning from buccal cusp to lingual cusp of second premolar and molar were acquired depending on the tooth axis. RESULTS In color-coded map, the biggest difference between intraoral scanning and dual-arch impression was seen (Pimpression and the smallest difference was seen between dual-arch and full-arch impression. CONCLUSION The two- and three-dimensional deviations between intraoral scanner and dual-arch impression was bigger than full-arch and dual-arch impression (P.05). PMID:26816576

  15. Probing the interactions of mitoxantrone with biomimetic membranes with electrochemical and spectroscopic techniques

    International Nuclear Information System (INIS)

    Nieciecka, Dorota; Królikowska, Agata; Krysinski, Paweł

    2015-01-01

    Graphical abstract: Display Omitted - Abstract: Mitoxantrone – an anticancer drug – was used to probe the interactions of this class of cytostatic molecules with biomimetic monolayers. The drug effect was monitored with electrochemical (cyclic voltammetry and electrochemical impedance spectroscopy), as well as spectroscopic techniques (surface enhanced Raman scattering), during its passive partitioning/penetration through the mixed Langmuir and Langmuir–Blodgett monolayers after their transfer on gold electrodes. This approach allowed us to discriminate between the drug interactions with hydrophilic head-group region and hydrophobic alkyl chains moiety of such monolayers

  16. Investigations of ultrafast charge dynamics in laser-irradiated targets by a self probing technique employing laser driven protons

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, H. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Kar, S., E-mail: s.kar@qub.ac.uk [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Cantono, G. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Department of Physics “E. Fermi”, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Research Unit Adriano Gozzini, via G. Moruzzi 1, Pisa 56124 (Italy); Nersisyan, G. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Brauckmann, S. [Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf (Germany); Doria, D.; Gwynne, D. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Macchi, A. [Department of Physics “E. Fermi”, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, Research Unit Adriano Gozzini, via G. Moruzzi 1, Pisa 56124 (Italy); Naughton, K. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom); Willi, O. [Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf (Germany); Lewis, C.L.S.; Borghesi, M. [School of Mathematics and Physics, Queen' s University Belfast, BT7 1NN (United Kingdom)

    2016-09-01

    The divergent and broadband proton beams produced by the target normal sheath acceleration mechanism provide the unique opportunity to probe, in a point-projection imaging scheme, the dynamics of the transient electric and magnetic fields produced during laser-plasma interactions. Commonly such experimental setup entails two intense laser beams, where the interaction produced by one beam is probed with the protons produced by the second. We present here experimental studies of the ultra-fast charge dynamics along a wire connected to laser irradiated target carried out by employing a ‘self’ proton probing arrangement – i.e. by connecting the wire to the target generating the probe protons. The experimental data shows that an electromagnetic pulse carrying a significant amount of charge is launched along the wire, which travels as a unified pulse of 10s of ps duration with a velocity close to speed of light. The experimental capabilities and the analysis procedure of this specific type of proton probing technique are discussed. - Highlights: • Prompt charging of laser irradiated target generates ultra-short EM pulses. • Its ultrafast propagation along a wire was studied by self-proton probing technique. • Self-proton probing technique is the proton probing with one laser pulse. • Pulse temporal profile and speed along the wire were measured with high resolution.

  17. 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

  18. A THEORETICAL FRAMEWORK FOR COMBINING TECHNIQUES THAT PROBE THE LINK BETWEEN GALAXIES AND DARK MATTER

    International Nuclear Information System (INIS)

    Leauthaud, Alexie; Tinker, Jeremy; Behroozi, Peter S.; Busha, Michael T.; Wechsler, Risa H.

    2011-01-01

    We develop a theoretical framework that combines measurements of galaxy-galaxy lensing, galaxy clustering, and the galaxy stellar mass function in a self-consistent manner. While considerable effort has been invested in exploring each of these probes individually, attempts to combine them are still in their infancy. These combinations have the potential to elucidate the galaxy-dark matter connection and the galaxy formation physics responsible for it, as well as to constrain cosmological parameters and to test the nature of gravity. In this paper, we focus on a theoretical model that describes the galaxy-dark matter connection based on standard halo occupation distribution techniques. Several key modifications enable us to extract additional parameters that determine the stellar-to-halo mass relation and to simultaneously fit data from multiple probes while allowing for independent binning schemes for each probe. We construct mock catalogs from numerical simulations to investigate the effects of sample variance and covariance for each probe. Finally, we analyze how trends in each of the three observables impact the derived parameters of the model. In particular, we investigate various features of the observed galaxy stellar mass function (low-mass slope, 'plateau', knee, and high-mass cutoff) and show how each feature is related to the underlying relationship between stellar and halo mass. We demonstrate that the observed 'plateau' feature in the stellar mass function at M * ∼ 2 x 10 10 M sun is due to the transition that occurs in the stellar-to-halo mass relation at M h ∼ 10 12 M sun from a low-mass power-law regime to a sub-exponential function at higher stellar mass.

  19. 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.

  20. Study of localized corrosion in aluminum alloys by the scanning reference electrode technique

    Science.gov (United States)

    Danford, M. D.

    1995-01-01

    Localized corrosion in 2219-T87 aluminum (Al) alloy, 2195 aluminum-lithium (Al-Li) alloy, and welded 2195 Al-Li alloy (4043 filler) have been investigated using the relatively new scanning reference electrode technique (SRET). Anodic sites are more frequent and of greater strength in the 2195 Al-Li alloy than in the 2219-T87 Al alloy, indicating a greater tendency toward pitting for the latter. However, the overall corrosion rates are about the same for these two alloys, as determined using the polarization resistance technique. In the welded 2195 Al-Li alloy, the weld bean is entirely cathodic, with rather strongly anodic heat affected zones (HAZ) bordering both sides, indicating a high probability of corrosion in the HAZ parallel to the weld bead.

  1. 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

  2. Effectiveness of different rescanning techniques for scanned proton radiotherapy in lung cancer patients

    Science.gov (United States)

    Engwall, E.; Glimelius, L.; Hynning, E.

    2018-05-01

    Non-small cell lung cancer (NSCLC) is a tumour type thought to be well-suited for proton radiotherapy. However, the lung region poses many problems related to organ motion and can for actively scanned beams induce severe interplay effects. In this study we investigate four mitigating rescanning techniques: (1) volumetric rescanning, (2) layered rescanning, (3) breath-sampled (BS) layered rescanning, and (4) continuous breath-sampled (CBS) layered rescanning. The breath-sampled methods will spread the layer rescans over a full breathing cycle, resulting in an improved averaging effect at the expense of longer treatment times. In CBS, we aim at further improving the averaging by delivering as many rescans as possible within one breathing cycle. The interplay effect was evaluated for 4D robustly optimized treatment plans (with and without rescanning) for seven NSCLC patients in the treatment planning system RayStation. The optimization and final dose calculation used a Monte Carlo dose engine to account for the density heterogeneities in the lung region. A realistic treatment delivery time structure given from the IBA ScanAlgo simulation tool served as basis for the interplay evaluation. Both slow (2.0 s) and fast (0.1 s) energy switching times were simulated. For all seven studied patients, rescanning improves the dose conformity to the target. The general trend is that the breath-sampled techniques are superior to layered and volumetric rescanning with respect to both target coverage and variability in dose to OARs. The spacing between rescans in our breath-sampled techniques is set at planning, based on the average breathing cycle length obtained in conjunction with CT acquisition. For moderately varied breathing cycle lengths between planning and delivery (up to 15%), the breath-sampled techniques still mitigate the interplay effect well. This shows the potential for smooth implementation at the clinic without additional motion monitoring equipment.

  3. Clinical value of CARE dose 4D technique in decreasing CT scanning dose of adult chest

    International Nuclear Information System (INIS)

    Wu Aiqin; Zheng Wenlong; Xu Chongyong; Fang Bidong; Ge Wen

    2011-01-01

    Objective: To investigate the value of CARE Dose 4D technique in decreasing radiation dose and improving image quality of multi-slice spiral CT in adult chest scanning. Methods: 100 patients of chest CT scanning were equally divided into study group and control group randomly. CARE Dose 4D Technique was used in study group. Effective mAs value, volume CT dose index (CTDI vol ) and dose length product (DLP) were displayed automatically in machine while chest scanning; those values and actual mAs value of every image were recorded respectively. The image quality at apex of lung, lower edge of aorta arch, middle area of left atrium and base of lung on every image of 400 images was judged and classified as three level (excellent, good, poor) by two deputy chief physicians with double blind method, the image noise at corresponding parts was measured. Results: While setting 80 mAs for quality reference mAs, the effective mAs value in study group most decreased 44 mAs than control group with an average decrease of 9.60 (12.0%), CTDI vol with 4.75 mGy with an average decrease of 0.95 mCy (11.0%), DLP 99.50% in study group, with 98.0% in control group. But it was higher at apex of lung and base of lung, lower at middle area of left atrium, and similar at lower edge of aorta arch in study group than contrast group. The image noise were lower at apex of lung and base of lung in study group than control group (t =6.299 and 2.332, all P<0.05), higher at middle area of left atrium in study group than control group (t=3.078, P<0.05) and similar at lower edge of aorta arch in study group than control group (t=1.191, P>0.05). Conclusions: CARE Dose 4D technique provides a function regulated mAs real-time on line, it not only raises utilization rate of radiation and decreases radiation dose, but also promises and increases image quality in chest CT scanning, and has some clinical significance. (authors)

  4. Induced modifications on algae photosynthetic activity monitored by pump-and-probe technique

    Energy Technology Data Exchange (ETDEWEB)

    Barbini, R; Colao, F; Fantoni, R; Palucci, A; Ribezzo, S [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione; Tarzillo, G; Carlozzi, P; Pelosi, E [CNR, Florence (Italy). Centro Studi Microorganismi Autotrofi

    1995-12-01

    The lidar fluorosensor system available at ENEA Frascati has been used for a series of laboratory measurements on brackish-water and marine phytoplankton grown in laboratory with the proper saline solution. The system, already used to measure the laser induced fluorescence spectra of different algae species and their detection limits, has been upgraded with a short pulse Nd:YAG laser and rearranged to test a new technique based on laser pump and probe excitation. Results of this new technique for remote monitoring of the in-vivo photosynthetic activity will be presented, as measured during a field campaign carried out in Florence during the Autumn 1993, where the effects of an actinic saturating light and different chemicals have also been checked.

  5. 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.

  6. Computed tomography automatic exposure control techniques in 18F-FDG oncology PET-CT scanning.

    Science.gov (United States)

    Iball, Gareth R; Tout, Deborah

    2014-04-01

    Computed tomography (CT) automatic exposure control (AEC) systems are now used in all modern PET-CT scanners. A collaborative study was undertaken to compare AEC techniques of the three major PET-CT manufacturers for fluorine-18 fluorodeoxyglucose half-body oncology imaging. An audit of 70 patients was performed for half-body CT scans taken on a GE Discovery 690, Philips Gemini TF and Siemens Biograph mCT (all 64-slice CT). Patient demographic and dose information was recorded and image noise was calculated as the SD of Hounsfield units in the liver. A direct comparison of the AEC systems was made by scanning a Rando phantom on all three systems for a range of AEC settings. The variation in dose and image quality with patient weight was significantly different for all three systems, with the GE system showing the largest variation in dose with weight and Philips the least. Image noise varied with patient weight in Philips and Siemens systems but was constant for all weights in GE. The z-axis mA profiles from the Rando phantom demonstrate that these differences are caused by the nature of the tube current modulation techniques applied. The mA profiles varied considerably according to the AEC settings used. CT AEC techniques from the three manufacturers yield significantly different tube current modulation patterns and hence deliver different doses and levels of image quality across a range of patient weights. Users should be aware of how their system works and of steps that could be taken to optimize imaging protocols.

  7. Possibilities and Challenges of Scanning Hard X-ray Spectro-microscopy Techniques in Material Sciences

    Directory of Open Access Journals (Sweden)

    Andrea Somogyi

    2015-06-01

    Full Text Available Scanning hard X-ray spectro-microscopic imaging opens unprecedented possibilities in the study of inhomogeneous samples at different length-scales. It gives insight into the spatial variation of the major and minor components, impurities and dopants of the sample, and their chemical and electronic states at micro- and nano-meter scales. Measuring, modelling and understanding novel properties of laterally confined structures are now attainable. The large penetration depth of hard X-rays (several keV to several 10 keV beam energy makes the study of layered and buried structures possible also in in situ and in operando conditions. The combination of different X-ray analytical techniques complementary to scanning spectro-microscopy, such as X-ray diffraction, X-ray excited optical luminescence, secondary ion mass spectrometry (SIMS and nano-SIMS, provides access to optical characteristics and strain and stress distributions. Complex sample environments (temperature, pressure, controlled atmosphere/vacuum, chemical environment are also possible and were demonstrated, and allow as well the combination with other analysis techniques (Raman spectroscopy, infrared imaging, mechanical tensile devices, etc. on precisely the very same area of the sample. The use of the coherence properties of X-rays from synchrotron sources is triggering emerging experimental imaging approaches with nanometer lateral resolution. New fast analytical possibilities pave the way towards statistically significant studies at multi- length-scales and three dimensional tomographic investigations. This paper gives an overview of these techniques and their recent achievements in the field of material sciences.

  8. 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.

  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

    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.

  11. 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.

  12. Electric field measurements on Cluster: comparing the double-probe and electron drift techniques

    Directory of Open Access Journals (Sweden)

    A. I. Eriksson

    2006-03-01

    Full Text Available The four Cluster satellites each carry two instruments designed for measuring the electric field: a double-probe instrument (EFW and an electron drift instrument (EDI. We compare data from the two instruments in a representative sample of plasma regions. The complementary merits and weaknesses of the two techniques are illustrated. EDI operations are confined to regions of magnetic fields above 30 nT and where wave activity and keV electron fluxes are not too high, while EFW can provide data everywhere, and can go far higher in sampling frequency than EDI. On the other hand, the EDI technique is immune to variations in the low energy plasma, while EFW sometimes detects significant nongeophysical electric fields, particularly in regions with drifting plasma, with ion energy (in eV below the spacecraft potential (in volts. We show that the polar cap is a particularly intricate region for the double-probe technique, where large nongeophysical fields regularly contaminate EFW measurments of the DC electric field. We present a model explaining this in terms of enhanced cold plasma wake effects appearing when the ion flow energy is higher than the thermal energy but below the spacecraft potential multiplied by the ion charge. We suggest that these conditions, which are typical of the polar wind and occur sporadically in other regions containing a significant low energy ion population, cause a large cold plasma wake behind the spacecraft, resulting in spurious electric fields in EFW data. This interpretation is supported by an analysis of the direction of the spurious electric field, and by showing that use of active potential control alleviates the situation.

  13. TU-CD-207-05: A Novel Digital Tomosynthesis System Using Orthogonal Scanning Technique: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J [Samsung Medical Center, Seoul (Korea, Republic of); Park, C [University of Florida Health Science Center, Gainesville, FL (United States); Kauweloa, K [UTHSCSA, San Antonio, TX (United States); Chung, Y; Han, Y [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Ju, S [Samsung Medical Center, Seoul, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: As an alternative to full tomographic imaging technique such as cone-beam computed tomography (CBCT), there is growing interest to adopt digital tomosynthesis (DTS) for the use of diagnostic as well as therapeutic applications. The aim of this study is to propose a new DTS system using novel orthogonal scanning technique, which can provide superior image quality DTS images compared to the conventional DTS scanning system. Methods: Unlike conventional DTS scanning system, the proposed DTS is reconstructed with two sets of orthogonal patient scans. 1) X-ray projections that are acquired along transverse trajectory and 2) an additional sets of X-ray projections acquired along the vertical direction at the mid angle of the previous transverse scan. To reconstruct DTS, we have used modified filtered backprojection technique to account for the different scanning directions of each projection set. We have evaluated the performance of our method using numerical planning CT data of liver cancer patient and a physical pelvis phantom experiment. The results were compared with conventional DTS techniques with single transverse and vertical scanning. Results: The experiments on both numerical simulation as well as physical experiment showed that the resolution as well as contrast of anatomical structures was much clearer using our method. Specifically, the image quality comparing with transversely scanned DTS showed that the edge and contrast of anatomical structures along Left-Right (LR) directions was comparable however, considerable discrepancy and enhancement could be observed along Superior-Inferior (SI) direction using our method. The opposite was observed when vertically scanned DTS was compared. Conclusion: In this study, we propose a novel DTS system using orthogonal scanning technique. The results indicated that the image quality of our novel DTS system was superior compared to conventional DTS system. This makes our DTS system potentially useful in various

  14. Comparison of different retreatment techniques and root canal sealers: a scanning electron microscopic study

    Directory of Open Access Journals (Sweden)

    Neslihan Simsek

    2014-05-01

    Full Text Available The aim of this study was to evaluate the effectiveness of two retreatment techniques, in terms of the operating time and scanning electron microscopy (SEM results, in removing three different root canal sealers from root canals that were previously filled with gutta-percha. Sixty extracted single-rooted human premolars were divided into three groups and filled with iRoot SP, MM Seal, and AH Plus sealers, along with gutta-percha, through a lateral compaction technique. Root canal fillings of the samples were removed by ESI ultrasonic tips or R-Endo files. The time to reach the working length was recorded. Longitudinally sectioned samples were examined under SEM magnification. Each picture was evaluated in terms of the residual debris. Data were statistically analyzed with the Kruskall-Wallis test. No statistically significant differences were found in terms of operating time (p>0.05. Significant differences in the number of debris-free dentinal tubules were found among the root canal thirds, but this finding was not influenced by the experimental group (p < 0.05. Resin sealer tags were observed inside the dentinal tubules in the MM Seal group. Under the conditions of this study, it may be established that there was no difference among the sealers and retreatment techniques.

  15. Spectral imaging technique for retinal perfusion detection using confocal scanning laser ophthalmoscopy

    Science.gov (United States)

    Rasta, Seyed Hossein; Manivannan, Ayyakkannu; Sharp, Peter F.

    2012-11-01

    To evaluate retinal perfusion in the human eye, a dual-wavelength confocal scanning laser ophthalmoscope (cSLO) was developed that provides spectral imaging of the fundus using a combination of red (670 nm) and near-infrared (810 nm) wavelengths. The image of the ocular fundus was analyzed to find out if quantitative measurements of the reflectivity of tissue permit assessment of the oxygen perfusion of tissue. We explored problems that affect the reproducibility of patient measurements such as non-uniformity errors on the image. For the first time, an image processing technique was designed and used to minimize the errors of oxygen saturation measurements by illumination correction in retina wide field by increasing SNR. Retinal images were taken from healthy and diabetic retinopathy eyes using the cSLO with a confocal aperture of 100 μm. The ratio image (RI) of red/IR, as oxygen saturation (SO2) index, was calculated for normal eyes. The image correction technique improved the reproducibility of the measurements. Average RI intensity variation of healthy retina tissue was determined within a range of about 5.5%. The capability of the new technique to discriminate oxygenation levels of retinal artery and vein was successfully demonstrated and showed good promise in the diagnosis of the perfused retina.

  16. All-optical optoacoustic microscopy based on probe beam deflection technique

    Directory of Open Access Journals (Sweden)

    Saher M. Maswadi

    2016-09-01

    Full Text Available Optoacoustic (OA microscopy using an all-optical system based on the probe beam deflection technique (PBDT for detection of laser-induced acoustic signals was investigated as an alternative to conventional piezoelectric transducers. PBDT provides a number of advantages for OA microscopy including (i efficient coupling of laser excitation energy to the samples being imaged through the probing laser beam, (ii undistorted coupling of acoustic waves to the detector without the need for separation of the optical and acoustic paths, (iii high sensitivity and (iv ultrawide bandwidth. Because of the unimpeded optical path in PBDT, diffraction-limited lateral resolution can be readily achieved. The sensitivity of the current PBDT sensor of 22 μV/Pa and its noise equivalent pressure (NEP of 11.4 Pa are comparable with these parameters of the optical micro-ring resonator and commercial piezoelectric ultrasonic transducers. Benefits of the present prototype OA microscope were demonstrated by successfully resolving micron-size details in histological sections of cardiac muscle.

  17. All-optical optoacoustic microscopy based on probe beam deflection technique.

    Science.gov (United States)

    Maswadi, Saher M; Ibey, Bennett L; Roth, Caleb C; Tsyboulski, Dmitri A; Beier, Hope T; Glickman, Randolph D; Oraevsky, Alexander A

    2016-09-01

    Optoacoustic (OA) microscopy using an all-optical system based on the probe beam deflection technique (PBDT) for detection of laser-induced acoustic signals was investigated as an alternative to conventional piezoelectric transducers. PBDT provides a number of advantages for OA microscopy including (i) efficient coupling of laser excitation energy to the samples being imaged through the probing laser beam, (ii) undistorted coupling of acoustic waves to the detector without the need for separation of the optical and acoustic paths, (iii) high sensitivity and (iv) ultrawide bandwidth. Because of the unimpeded optical path in PBDT, diffraction-limited lateral resolution can be readily achieved. The sensitivity of the current PBDT sensor of 22 μV/Pa and its noise equivalent pressure (NEP) of 11.4 Pa are comparable with these parameters of the optical micro-ring resonator and commercial piezoelectric ultrasonic transducers. Benefits of the present prototype OA microscope were demonstrated by successfully resolving micron-size details in histological sections of cardiac muscle.

  18. Remote defect imaging for plate-like structures based on the scanning laser source technique

    Science.gov (United States)

    Hayashi, Takahiro; Maeda, Atsuya; Nakao, Shogo

    2018-04-01

    In defect imaging with a scanning laser source technique, the use of a fixed receiver realizes stable measurements of flexural waves generated by laser at multiple rastering points. This study discussed the defect imaging by remote measurements using a laser Doppler vibrometer as a receiver. Narrow-band burst waves were generated by modulating laser pulse trains of a fiber laser to enhance signal to noise ratio in frequency domain. Averaging three images obtained at three different frequencies suppressed spurious distributions due to resonance. The experimental system equipped with these newly-devised means enabled us to visualize defects and adhesive objects in plate-like structures such as a plate with complex geometries and a branch pipe.

  19. Measurements of nonlinear optical properties of PVDF/ZnO using Z-scan technique

    Energy Technology Data Exchange (ETDEWEB)

    Shanshool, Haider Mohammed, E-mail: haidshan62@gmail.com [Ministry of Science and Technology, Baghdad (Iraq); Yahaya, Muhammad [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor (Malaysia); Yunus, Wan Mahmood Mat [Department of Physics, Faculty of Science, University Putra Malaysia, Serdang (Malaysia); Abdullah, Ibtisam Yahya [Department of Physics, College of Science, University of Mosul, Mosul (Iraq)

    2015-10-15

    The nonlinear optical properties of ZnO nanoparticles dispersed in poly (vinylidene fluoride) (PVDF) polymer are investigated. PVDF/ZnO nanocomposites were prepared by mixing different concentrations of ZnO nanoparticles, as the filler, with PVDF, as the polymer matrix, using casting method. Acetone was used as a solvent for the polymer. FTIR spectra of the samples were analyzed thus confirming the formation of α and β phases. The absorbance spectra of the samples were obtained, thereby showing high absorption in the UV region. The linear absorption coefficient was calculated. The single-beam Z-scan technique was used to measure the nonlinear refractive index and the nonlinear absorption coefficient of the PVDF/ZnO nanocomposite samples. We observed that the nonlinear refractive index is in the order of 10{sup -13} cm{sup 2}/W with the negative sign, whereas the nonlinear absorption coefficient is in the order of 10{sup -8} cm/W. (author)

  20. Studies of localized corrosion in welded aluminum alloys by the scanning reference electrode technique

    Science.gov (United States)

    Danford, M. D.; Nunes, A. C.

    1995-01-01

    Localized corrosion in welded samples of 2219-T87 Al alloy (2319 filler), 2090 Al-Li alloy (4043 and 2319 fillers), and 2195 Al-Li alloy (4043 and 2319 fillers) has been investigated using the relatively new scanning reference electrode technique. The weld beads are cathodic in all cases, leading to reduced anode/cathode ratios. A reduction in anode/cathode ratio leads to an increase in the corrosion rates of the welded metals, in agreement with results obtained in previous electrochemical and stress corrosion studies involving the overall corrosion rates of welded samples. The cathodic weld beads are bordered on both sides by strong anodic regions, with high propensity for corrosion.

  1. Dual ring multilayer ionization chamber and theory-based correction technique for scanning proton therapy.

    Science.gov (United States)

    Takayanagi, Taisuke; Nihongi, Hideaki; Nishiuchi, Hideaki; Tadokoro, Masahiro; Ito, Yuki; Nakashima, Chihiro; Fujitaka, Shinichiro; Umezawa, Masumi; Matsuda, Koji; Sakae, Takeji; Terunuma, Toshiyuki

    2016-07-01

    To develop a multilayer ionization chamber (MLIC) and a correction technique that suppresses differences between the MLIC and water phantom measurements in order to achieve fast and accurate depth dose measurements in pencil beam scanning proton therapy. The authors distinguish between a calibration procedure and an additional correction: 1-the calibration for variations in the air gap thickness and the electrometer gains is addressed without involving measurements in water; 2-the correction is addressed to suppress the difference between depth dose profiles in water and in the MLIC materials due to the nuclear interaction cross sections by a semiempirical model tuned by using measurements in water. In the correction technique, raw MLIC data are obtained for each energy layer and integrated after multiplying them by the correction factor because the correction factor depends on incident energy. The MLIC described here has been designed especially for pencil beam scanning proton therapy. This MLIC is called a dual ring multilayer ionization chamber (DRMLIC). The shape of the electrodes allows the DRMLIC to measure both the percentage depth dose (PDD) and integrated depth dose (IDD) because ionization electrons are collected from inner and outer air gaps independently. IDDs for which the beam energies were 71.6, 120.6, 159, 180.6, and 221.4 MeV were measured and compared with water phantom results. Furthermore, the measured PDDs along the central axis of the proton field with a nominal field size of 10 × 10 cm(2) were compared. The spread out Bragg peak was 20 cm for fields with a range of 30.6 and 3 cm for fields with a range of 6.9 cm. The IDDs measured with the DRMLIC using the correction technique were consistent with those that of the water phantom; except for the beam energy of 71.6 MeV, all of the points satisfied the 1% dose/1 mm distance to agreement criterion of the gamma index. The 71.6 MeV depth dose profile showed slight differences in the shallow

  2. Dual ring multilayer ionization chamber and theory-based correction technique for scanning proton therapy

    International Nuclear Information System (INIS)

    Takayanagi, Taisuke; Nishiuchi, Hideaki; Fujitaka, Shinichiro; Umezawa, Masumi; Nihongi, Hideaki; Tadokoro, Masahiro; Ito, Yuki; Nakashima, Chihiro; Matsuda, Koji; Sakae, Takeji; Terunuma, Toshiyuki

    2016-01-01

    Purpose: To develop a multilayer ionization chamber (MLIC) and a correction technique that suppresses differences between the MLIC and water phantom measurements in order to achieve fast and accurate depth dose measurements in pencil beam scanning proton therapy. Methods: The authors distinguish between a calibration procedure and an additional correction: 1—the calibration for variations in the air gap thickness and the electrometer gains is addressed without involving measurements in water; 2—the correction is addressed to suppress the difference between depth dose profiles in water and in the MLIC materials due to the nuclear interaction cross sections by a semiempirical model tuned by using measurements in water. In the correction technique, raw MLIC data are obtained for each energy layer and integrated after multiplying them by the correction factor because the correction factor depends on incident energy. The MLIC described here has been designed especially for pencil beam scanning proton therapy. This MLIC is called a dual ring multilayer ionization chamber (DRMLIC). The shape of the electrodes allows the DRMLIC to measure both the percentage depth dose (PDD) and integrated depth dose (IDD) because ionization electrons are collected from inner and outer air gaps independently. Results: IDDs for which the beam energies were 71.6, 120.6, 159, 180.6, and 221.4 MeV were measured and compared with water phantom results. Furthermore, the measured PDDs along the central axis of the proton field with a nominal field size of 10 × 10 cm 2 were compared. The spread out Bragg peak was 20 cm for fields with a range of 30.6 and 3 cm for fields with a range of 6.9 cm. The IDDs measured with the DRMLIC using the correction technique were consistent with those that of the water phantom; except for the beam energy of 71.6 MeV, all of the points satisfied the 1% dose/1 mm distance to agreement criterion of the gamma index. The 71.6 MeV depth dose profile showed slight

  3. Development of techniques and methods for evaluation of quality of scanned image in mammography

    International Nuclear Information System (INIS)

    Carmo Santana, P. do; Nogueira, M.S.

    2008-01-01

    Cancer is the second cause of death in the Brazilian female population and breast cancer is the most frequent neoplasm amongst women. Mammography is an essential tool for diagnosis and early detection of this disease. In order to be effective, the mammography must be of good quality. The Brazilian College of Radiology (CBR), the National Agency for Health Surveillance (ANVISA) and international bodies recommend standards of practice for mammography. Due to the risk of ionizing radiation, techniques that minimize dose and optimize image quality are essential to ensure that all women are submitted to mammography procedures of high quality for the detection of breast cancer. In this research were analyzed components of the image treatment via digital and developed methods and techniques of analysis aiming the detection of structures for medical diagnosis, decreasing variations due to subjectivity. It used free software Image J, to make the evaluations of the information contained in the scanned images. We use the scanned images of calibration of a simulated breast to calibrate the program Image J. Thus, it was able to correctly convert the values of the scale of shades of gray in optical density values of presenting the standard deviation for each measure held. Applying the test t-student noticed that the values obtained with the digital system to the level of contrast and spatial resolution are consistent with the results obtained so subjective, since there was no significant difference (p <0.05) for all comparisons evaluated. Since then, this methodology is recommended in routine evaluations of services of mammography. (author)

  4. Energy transfer in isolated LHC II studied by femtosecond pump-probe technique

    CERN Document Server

    Yang Yi; Liu Yuan; Liu Wei Min; Zhu Rong Yi; Qian Shi Xiong; Xu Chun He

    2003-01-01

    Excitation energy transfer in the isolated light-harvesting chlorophyll (Chl)-a/b protein complex of photosystem II (LHC II) was studied by the one-colour pump-probe technique with femtosecond time resolution. After exciting Chl-b by 638nm beam, the dynamic behaviour shows that the ultrafast energy transfer from Chl-b at positions of B2, B3, and B5 to the corresponding Chl-a molecules in monomeric subunit of LHC II is in the time scale of 230fs. While with the excitation of Chl-a at 678nm, the energy transfer between excitons of Chl-a molecules has the lifetime of about 370 fs, and two other slow decay components are due to the energy transfer between different Chl-a molecules in a monomeric subunit of LHC II or in different subunits, or due to change of molecular conformation. (20 refs).

  5. Proving the capabilities of the phased-array probe/ALOK inspection technique

    International Nuclear Information System (INIS)

    Bohn, H.; Kroening, M.; Rathgeb, W.; Gebhardt, W.; Kappes, W.; Barbian, O.A.

    1987-01-01

    The capability of the ALOK phased-probe-array inspection technique results from the simplicity of the testing system structure, the reflector detection and identification by means of transit time curves, and the analytical capacity of the system. Testing times are shortened, with the test results meeting the current standards, and further possibilities being given: Areas that could so far only be inspected with difficulty of not at all, can be examined, thanks to the compact equipment and without having to modify the system, very informative analysis measurements for interpreting indications can be made. Furthermore, it may be expected from the testing practice that descriptions of indications will become more reliable and reproducible, due to transit time curve identification. In addition to conventional criteria for reflector evaluation, the potential of transit time curve identification, and flaw boundary imaging of the reconstruction image can be utilized. (orig.)

  6. Optical techniques for probing the excited state dynamics of quantum dot solids

    Energy Technology Data Exchange (ETDEWEB)

    Moroz, P.; Kholmicheva, N.; Razgoniaeva, N. [Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH 43402 (United States); Department of Physics, Bowling Green State University, Bowling Green, OH 43402 (United States); Burchfield, D. [Department of Chemistry, Bowling Green State University, Bowling Green, OH 43402 (United States); Sharma, N.; Acharya, A. [Department of Physics, Bowling Green State University, Bowling Green, OH 43402 (United States); Zamkov, M., E-mail: zamkovm@bgsu.edu [Center for Photochemical Sciences, Bowling Green State University, Bowling Green, OH 43402 (United States); Department of Physics, Bowling Green State University, Bowling Green, OH 43402 (United States)

    2016-06-01

    Highlights: • Optical techniques represent a powerful tool for probing exciton diffusion in QD solids. • Exciton dissociation in QD solids is caused by charge tunneling to traps and other dots. • Exciton and free-carrier lifetimes are given by fast and slow components of PL decay. • Surface PL offers valuable information on the type and density of traps in QD solids. - Abstract: Quantum dot (QD) solids represent an important class of functional materials that holds strong promise for future applications in technology. Their optoelectronic properties are determined by energy diffusion processes, which character can often be inferred from the temporal and spectral analysis of the film’s photoluminescence (PL). Here, optical techniques based on PL lifetime, bulk quenching, and temperature-dependent PL will be discussed. These techniques complement the electrical conductivity measurements by mapping the flow of optically induced excitons through undepleted, contact-free films with an unprecedented temporal and spatial resolution. By correlating the QD solid morphology with the ensuing photoluminescence (PL) dynamics, these methods allow estimating important transport characteristics, including exciton and charge carrier diffusion lengths, the rate of interparticle energy transfer, carrier mobility, and the exciton diffusivity. The review will cover most popular PL-based strategies and summarize the key experimental findings resulting from these works.

  7. 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.

  8. 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

  9. The 100th anniversary of the four-point probe technique: the role of probe geometries in isotropic and anisotropic systems

    International Nuclear Information System (INIS)

    Miccoli, I; Edler, F; Pfnür, H; Tegenkamp, C

    2015-01-01

    The electrical conductivity of solid-state matter is a fundamental physical property and can be precisely derived from the resistance measured via the four-point probe technique excluding contributions from parasitic contact resistances. Over time, this method has become an interdisciplinary characterization tool in materials science, semiconductor industries, geology, physics, etc, and is employed for both fundamental and application-driven research. However, the correct derivation of the conductivity is a demanding task which faces several difficulties, e.g. the homogeneity of the sample or the isotropy of the phases. In addition, these sample-specific characteristics are intimately related to technical constraints such as the probe geometry and size of the sample. In particular, the latter is of importance for nanostructures which can now be probed technically on very small length scales. On the occasion of the 100th anniversary of the four-point probe technique, introduced by Frank Wenner, in this review we revisit and discuss various correction factors which are mandatory for an accurate derivation of the resistivity from the measured resistance. Among others, sample thickness, dimensionality, anisotropy, and the relative size and geometry of the sample with respect to the contact assembly are considered. We are also able to derive the correction factors for 2D anisotropic systems on circular finite areas with variable probe spacings. All these aspects are illustrated by state-of-the-art experiments carried out using a four-tip STM/SEM system. We are aware that this review article can only cover some of the most important topics. Regarding further aspects, e.g. technical realizations, the influence of inhomogeneities or different transport regimes, etc, we refer to other review articles in this field. (topical review)

  10. Multiplex Ligation-Dependent Probe Amplification Technique for Copy Number Analysis on Small Amounts of DNA Material

    DEFF Research Database (Denmark)

    Sørensen, Karina; Andersen, Paal; Larsen, Lars

    2008-01-01

    The multiplex ligation-dependent probe amplification (MLPA) technique is a sensitive technique for relative quantification of up to 50 different nucleic acid sequences in a single reaction, and the technique is routinely used for copy number analysis in various syndromes and diseases. The aim...... of the study was to exploit the potential of MLPA when the DNA material is limited. The DNA concentration required in standard MLPA analysis is not attainable from dried blood spot samples (DBSS) often used in neonatal screening programs. A novel design of MLPA probes has been developed to permit for MLPA...... analysis on small amounts of DNA. Six patients with congenital adrenal hyperplasia (CAH) were used in this study. DNA was extracted from both whole blood and DBSS and subjected to MLPA analysis using normal and modified probes. Results were analyzed using GeneMarker and manual Excel analysis. A total...

  11. Technique improvement of thoracoabdominal CT scan for patients with arm-raising disability

    International Nuclear Information System (INIS)

    Yuan Zhidong; Liu Yuanjian; Jiang Guoyin; Feng Fei; Wang Chenglin; Liu Pengcheng

    2010-01-01

    Objective: To explore a new scanning technique to reduce and avoid image artifacts of thoracoabdominal CT and improve image quality for patients who cannot raise their arms. Methods: Sixty-one patients with arm-raising disability between March 2004 and May 2009 were enrolled in the study. Thirty-one cases before June 2007 were scanned with their arms beside their body (control group), 30 cases after June 2007 were scanned with their arms shifting to different imaging planes of the spine (study group), and another 30 patients who can raising their arms were taken as routine group. The images artifacts were blindly evaluated by 5-points scale (severe, less severe, moderate, minimum and no artifact) by 2 experienced CT technologists and one radiologist and compared between the three groups (X 2 test). CT values and its noise of the liver with or without artifact of the three groups were measured and analyzed by one-way ANOVA test. Results: In the control group, 11 cases had severe, 15 cases had less severe, 5 cases had moderate. In the study group, 6 cases had moderate, 15 cases had minimum, 9 cases had no artifact. In the routine group, 8 cases minimum and 22 cases had no artifact. Image quality was significantly improved in the study group compared to the conventional group where X 2 =95.32 and P<0.01. CT value and the noise of the liver without artifact were (54.5 ± 3.0) HU and 10.7 ± 2.4 in the control group, (52.0 ± 3.5) HU and 10.7 ± 0.5 in the study group, (53.7 ± 3.1) HU and 9.9 ± 0.5 in the routine group, respectively. CT value and noise of the liver with artifact were (41.7 ± 8.4) HU and 17.9 ± 2.6 in control group, (53.1 ± 6.9) HU and 11.0 ± 0.7 in the study group, (54.1 ± 2.4) HU and 9.9 ± 0.5 in the routine group, respectively. The CT value and its noise variation with artifact were significantly higher in the control group than the study group and the control group, where F=36.352, 235.848, respectively and P<0.01. Conclusion: The image

  12. A scanning tunneling microscopy based potentiometry technique and its application to the local sensing of the spin Hall effect

    Directory of Open Access Journals (Sweden)

    Ting Xie

    2017-12-01

    Full Text Available A scanning tunneling microscopy based potentiometry technique for the measurements of the local surface electric potential is presented. A voltage compensation circuit based on this potentiometry technique is developed and employed to maintain a desired tunneling voltage independent of the bias current flow through the film. The application of this potentiometry technique to the local sensing of the spin Hall effect is outlined and some experimental results are reported.

  13. Nonlinear Optical Characteristics of Crystal VioletDye Doped Polystyrene Films by Using Z-Scan Technique

    Directory of Open Access Journals (Sweden)

    Mahasin F. Hadi

    2017-07-01

    Full Text Available Z-scan technique was employed to study the nonlinear optical properties (nonlinear refractive index and nonlinear absorption coefficient for crystal violet doped polystyrene films as a function of doping ratio in chloroform solvent. Samples exhibits in closed aperture Z-scan positive nonlinear refraction (self-focusing. While in the open aperture Z-scan gives reverse saturation absorption (RSA (positive absorption for all film with different doping ratio making samples candidates for optical limiting devices for protection of sensors and eyes from energetic laser light pulses under the experimental conditions.

  14. A novel technique for reference point generation to aid in intraoral scan alignment.

    Science.gov (United States)

    Renne, Walter G; Evans, Zachary P; Mennito, Anthony; Ludlow, Mark

    2017-11-12

    When using a completely digital workflow on larger prosthetic cases it is often difficult to communicate to the laboratory or chairside Computer Aided Design and Computer Aided Manufacturing system the provisional prosthetic information. The problem arises when common hard tissue data points are limited or non-existent such as in complete arch cases in which the 3D model of the complete arch provisional restorations must be aligned perfectly with the 3D model of the complete arch preparations. In these instances, soft tissue is not enough to ensure an accurate automatic or manual alignment due to a lack of well-defined reference points. A new technique is proposed for the proper digital alignment of the 3D virtual model of the provisional prosthetic to the 3D virtual model of the prepared teeth in cases where common and coincident hard tissue data points are limited. Clinical considerations: A technique is described in which fiducial composite resin dots are temporarily placed on the intraoral keratinized tissue in strategic locations prior to final impressions. These fiducial dots provide coincident and clear 3D data points that when scanned into a digital impression allow superimposition of the 3D models. Composite resin dots on keratinized tissue were successful at allowing accurate merging of provisional restoration and post-preparation 3D models for the purpose of using the provisional restorations as a guide for final CLINICAL SIGNIFICANCE: Composite resin dots placed temporarily on attached tissue were successful at allowing accurate merging of the provisional restoration 3D models to the preparation 3D models for the purposes of using the provisional restorations as a guide for final restoration design and manufacturing. In this case, they allowed precise superimposition of the 3D models made in the absence of any other hard tissue reference points, resulting in the fabrication of ideal final restorations. © 2017 Wiley Periodicals, Inc.

  15. Spiral CT scanning technique in the detection of aspiration of LEGO foreign bodies

    International Nuclear Information System (INIS)

    Applegate, K.E.; Dardinger, J.T.; Herts, B.R.; Davros, W.J.; Obuchowski, N.A.; Lieber, M.L.; Maneker, A.

    2001-01-01

    Background:. Radiolucent foreign bodies (FBs) such as plastic objects and toys remain difficult to identify on conventional radiographs of the neck and chest. Children may present with a variety of respiratory complaints, which may or may not be due to a FB. Objective: To determine whether radiolucent FBs such as plastic LEGOs and peanuts can be seen in the tracheobronchial tree or esophagus using low-dose spiral CT, and, if visible, to determine the optimal CT imaging technique. Materials and methods: Multiple spiral sequences were performed while varying the CT parameters and the presence and location of FBs in either the trachea or the esophagus first on a neck phantom and then a cadaver. Sequences were rated by three radiologists blinded to the presence of a FB using a single scoring system. Results: The LEGO was well visualized in the trachea by all three readers (both lung and soft-tissue windowing: combined sensitivity 89 %, combined specificity 89 %) and to a lesser extent in the esophagus (combined sensitivity 31 %, combined specificity 100 %). The peanut was not well visualized (combined sensitivity < 35 %). The optimal technique for visualizing the LEGO was 120 kV, 90 mA, 3-mm collimation, 0.75 s/revolution, and 2.0 pitch. This allowed for coverage of the cadaver tracheobronchial tree (approximately 11 cm) in about 18 s. Although statistical power was low for detecting significant differences, all three readers noted higher average confidence ratings with lung windowing among 18 LEGO-in-trachea scans. Conclusion: Rapid, low-dose spiral CT may be used to visualize LEGO FBs in the airway or esophagus. Peanuts were not well visualized. (orig.)

  16. Skimming and Scanning Techniques to Assist EFL Students in Understanding English Reading Texts

    Directory of Open Access Journals (Sweden)

    QISMULLAH YUSUF

    2017-12-01

    Full Text Available This research aimed to find out whether the skimming and scanning techniques (SST can improve EFL students’ English reading comprehension in recount texts, especially on identifying the main ideas and detail information, in a senior high school in Meulaboh, Aceh, Indonesia. A number of 32 eleventh grade students participated in this study, and the one group pre-test and post-test design were used. Data collection was from a pre-test and a post-test. In analyzing the data, statistics was used. The results showed that the mean score of the pre-test was 45 and the post-test was 65, with 20 points of improvement. Furthermore, the result of t-test was 4.7, while the critical value of 0.05 significant level was 2.4, with the degree of freedom at 23. Since t-test>t-score, thus SST improved the students’ reading comprehension in this study. Nevertheless, the paper further discusses some setbacks while implementing SST in the classroom.

  17. Development of new techniques for scanning electron microscope observation using ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto, Satoshi; Sugimura, Masaharu; Kageyama, Hitoshi [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); JST, CREST, Kawaguchi, Saitama 332-0012 (Japan); Torimoto, Tsukasa [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); JST, CREST, Kawaguchi, Saitama 332-0012 (Japan); Kuwabata, Susumu [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); JST, CREST, Kawaguchi, Saitama 332-0012 (Japan)], E-mail: kuwabata@chem.eng.osaka-u.ac.jp

    2008-09-01

    Based on our previous discovery that ionic liquid (IL) can be observed by a scanning electron microscope (SEM) without charging the liquid, we have developed several novel techniques for SEM observation. Coating of insulating sample with IL is useful for providing electronic conductivity to the samples like metal or carbon coating by vacuum vapor deposition. In this case, dilution of the IL with appropriate volatile solvent like alcohol is effective for coating thin layer of IL on the sample. As a biological sample, seaweed including IL was attempted to be observed by SEM. A seaweed leaf swollen by water was put in an IL bath and the bath was put in an outgassed desiccator to replace water in the seaweed leaf with IL. The resulting sample gave a SEM image of the swollen seaweed whose thickness was several times larger than dried one. Furthermore, the introduction of the IL in vacuum chamber allowed us to develop the in situ electrochemical SEM observation system. Using this system, we observed changes in polypyrrole film thickness caused by the redox reaction of the film and the electrochemical deposition of silver and its oxidative dissolution. It was also found that the energy dispersive X-ray fluorescence (EDX) analysis was available even for the electrode polarized in IL.

  18. Development of new techniques for scanning electron microscope observation using ionic liquid

    International Nuclear Information System (INIS)

    Arimoto, Satoshi; Sugimura, Masaharu; Kageyama, Hitoshi; Torimoto, Tsukasa; Kuwabata, Susumu

    2008-01-01

    Based on our previous discovery that ionic liquid (IL) can be observed by a scanning electron microscope (SEM) without charging the liquid, we have developed several novel techniques for SEM observation. Coating of insulating sample with IL is useful for providing electronic conductivity to the samples like metal or carbon coating by vacuum vapor deposition. In this case, dilution of the IL with appropriate volatile solvent like alcohol is effective for coating thin layer of IL on the sample. As a biological sample, seaweed including IL was attempted to be observed by SEM. A seaweed leaf swollen by water was put in an IL bath and the bath was put in an outgassed desiccator to replace water in the seaweed leaf with IL. The resulting sample gave a SEM image of the swollen seaweed whose thickness was several times larger than dried one. Furthermore, the introduction of the IL in vacuum chamber allowed us to develop the in situ electrochemical SEM observation system. Using this system, we observed changes in polypyrrole film thickness caused by the redox reaction of the film and the electrochemical deposition of silver and its oxidative dissolution. It was also found that the energy dispersive X-ray fluorescence (EDX) analysis was available even for the electrode polarized in IL

  19. Valuation of using saline flush technique of contrast medium on abdominal multidetector row CT scanning

    International Nuclear Information System (INIS)

    Zhao Hong; Wang Ying; He Yanli; Liu Xiaobing; Bao Shiliang; Han Mingjun

    2006-01-01

    Objective: The purpose of this study was to compare the enhancement degree of abdomen organs and vessels after different amount of contrast medium using saline flush in abdomen MDCT scanning, which aimed to not affect contrast enhancement, decreased the amount of contrast medium, and reduced the side-effect. Methods: This study group consisted of 75 patients who were referred for contrast enhanced abdominal MDCT for various reasons. Patients were allocated into three groups: injection of 100ml of contrast medium only (A group), injection of 80ml pushed with 20ml of saline solution (B group), and injection of 70ml pushed with 30ml of saline solution (C group). Attenuation values were measured from the liver, spleen, pancreas, kidney, aorta, portal vein, and inferior vena cava in 33 second and 80 second of imaging after injection contrast medium. Results: The portal venous phases of the spleen, pancreas, kidney, aorta, portal vein had statistically significant difference among groups A, B and C. Post hoc test showed statistically significant difference between A group and C group, But no statistically significant difference during the portal venous phases of the pancreas and the kidney between A group and B group. Conclusion: Using a saline flush technique after the injection contrast medium in abdominal MDCT reduced waste of contrast medium and decrease in nephrotoxicity, at the same time, it would not lose important diagnostic information and saved patients cost for the contrast medium. (authors)

  20. Development of dynamic 3-D surface profilometry using stroboscopic interferometric measurement and vertical scanning techniques

    Energy Technology Data Exchange (ETDEWEB)

    Fan, K-C [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chen, L-C [Graduate Institute of Automation Technology, National Taipei University of Technology, 1 Sec. 3 Chung-Hsiao East Rd, Taipei, 106, Taiwan (China); Lin, C-D [Department of Mechanical Engineering, National Taiwan University, 1, Sec. 4 Roosevelt Rd, Taipei, Taiwan (China); Chang, Calvin C [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Kuo, C-F [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China); Chou, J-T [Industrial Technology Research Institute, Centre for Measurement Standards, 321 Sec. 2, Kuang Fu Rd, Hsinchu, Taiwan, 300 (China)

    2005-01-01

    The main objective of this technical advance is to provide a single optical interferometric framework and methodology to be capable of delivering both nano-scale static and dynamic surface profilometry. Microscopic interferometry is a powerful technique for static and dynamic characterization of micro (opto) electromechanical systems (M (O) EMS). In view of this need, a microscopic prototype based on white-light stroboscopic interferometry and the white light vertical scanning principle, was developed to achieve dynamic full-field profilometry and characterization of MEMS devices. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterization of dynamic behaviours of the device. The full-field second-mode vibration at a vibratory frequency of 68.60 kHz can be fully characterized and 3-5 nm of vertical measurement resolution as well as tens of micrometers of vertical measurement range can be easily achieved.

  1. 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.

  2. 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

  3. 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.)

  4. Developing of FTIR- and new probe technique for combustion gas analysis; Utveckling av FTIR- och sondteknik foer gasanalys i foerbraenningsrum

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Annika; Andersson, Christer [Vattenfall Utveckling AB, Stockholm (Sweden); Thulin, C [Swedish National Testing and Research Inst., Boraas (Sweden); Karlsson, Maria; Aamand, L E [Chalmers Univ. of Technology, Goeteborg (Sweden)

    1996-08-01

    The objective of the reported project has been to develop and field test a versatile measurement system for combustion gases based on the FTIR technique. The project has included the following stages: Development of gas sampling methods, Further development of the FTIR technique, Field testing of the measurement system. The development of evaluation routines based on CLS and PLS methods has lead to the conclusion that both methods are well suited for the application in question, which enables an automation of the evaluation procedure. However, the elaboration of versatile and quality controlled methods is time consuming and the application requires a qualified user. With the dilution probe prototype, a satisfactory rejection of particles is achieved at the same time as a good mixing of the dilution gas and the sample gas takes place. Sampling is performed without using a filter at the probe tip. The intended function of the probe requires that most particles can be rejected without giving rise to a too high dilution ratio. This was achieved in the middle and upper part of the CFB boiler. Comparisons of measurement data from field measurements with the developed probe concept and the `conventional` CTH extractive probe show that the results are in good agreement in many cases, but also that interesting discrepancies exist. Sampling artefacts have been noticed for the gases HCN and SO{sub 2}, where HCN and SO{sub 2} are found in higher concentrations when sampling with the dilution probe. Analyzed concentrations of CO and hydrocarbons (methane, ethene and acetylene) are throughout all the measurements lower when the dilution probe is used. 21 refs, 34 figs, 29 tabs

  5. B-scan technique for localization and characterization of fatigue cracks around fastener holes in multi-layered structures

    Science.gov (United States)

    Hopkins, Deborah; Datuin, Marvin; Aldrin, John; Warchol, Mark; Warchol, Lyudmila; Forsyth, David

    2018-04-01

    The work presented here aims to develop and transition angled-beam shear-wave inspection techniques for crack localization at fastener sites in multi-layer aircraft structures. This requires moving beyond detection to achieve reliable crack location and size, thereby providing invaluable information for maintenance actions and service-life management. The technique presented is based on imaging cracks in "True" B-scans (depth view projected in the sheets along the beam path). The crack traces that contribute to localization in the True B-scans depend on small, diffracted signals from the crack edges and tips that are visible in simulations and experimental data acquired with sufficient gain. The most recent work shows that cracks rotated toward and away from the central ultrasonic beam also yield crack traces in True B-scans that allow localization in simulations, even for large obtuse angles where experimental and simulation results show very small or no indications in the C-scans. Similarly, for two sheets joined by sealant, simulations show that cracks in the second sheet can be located in True B-scans for all locations studied: cracks that intersect the front or back wall of the second sheet, as well as relatively small mid-bore cracks. These results are consistent with previous model verification and sensitivity studies that demonstrate crack localization in True B-scans for a single sheet and cracks perpendicular to the ultrasonic beam.

  6. Measurement Verification of Plane Wave Synthesis Technique Based on Multi-probe MIMO-OTA Setup

    DEFF Research Database (Denmark)

    Fan, Wei; Carreño, Xavier; Nielsen, Jesper Ødum

    2012-01-01

    Standardization work for MIMO OTA testing methods is currently ongoing, where a multi-probe anechoic chamber based solution is an important candidate. In this paper, the probes located on an OTA ring are used to synthesize a plane wave field in the center of the OTA ring. This paper investigates...

  7. Survey regarding the clinical practice of cardiac CT in Germany. Indications, scanning technique and reporting

    Energy Technology Data Exchange (ETDEWEB)

    Maurer, Marc H.; Hamm, B.; Dewey, M. [Inst. fuer Radiologie, Charite - Universitaetsmedizin Berlin (Germany)

    2009-12-15

    Purpose: to obtain an overview of the current clinical practice of cardiac computed tomography (CT) in Germany. Materials and methods: a 30-item question-naire was mailed to 149 providers of cardiac CT in Germany. The items asked about indications, scanning technique and reporting, data storage, and cost of the examination. Results: overall 45 questionnaires could be analyzed (30%). The majority of centers (76%, 34 of 45 centers) used CT scanners of the latest generation (at least 64 rows). The most common appropriate indications were exclusion of coronary artery disease (91%, 41/45), coronary anomalies (80%, 36/45), and follow-up after coronary artery bypass grafting (53%, 24/45). Each center examined on average 243 {+-} 310 patients in 2007 and the number of centers performing cardiac CT increased significantly in 2007 (p = 0.035) compared with the preceding year. Most used sublingual nitroglycerin (84%, 38/45; median of 2 sprays = 0.8 mg) and/or a beta blocker (86%, 39/44; median of 5 mg IV, median heart rate threshold: 70 beats/min). Many providers used ECG-triggered tube current modulation (65%, 29/44) and/or adjusted the tube current to the body mass index or body weight (63%, 28/44). A median slice thickness of 0.75 mm with a 0.5 mm increment and a 20 cm field-of-view was most commonly used. Source images in orthogonal planes (96%, 43/45), curved MPRs (93%, 42/45), and thin-slice MIPs (69%, 31/45) were used most frequently for interpretation. Extracardiac structures were also evaluated by 84% of the centers (38/45). The mean examination time was 16.2 min and reporting took an average of 28.8 min. (orig.)

  8. Spiral CT scanning technique in the detection of aspiration of LEGO foreign bodies.

    Science.gov (United States)

    Applegate, K E; Dardinger, J T; Lieber, M L; Herts, B R; Davros, W J; Obuchowski, N A; Maneker, A

    2001-12-01

    Radiolucent foreign bodies (FBs) such as plastic objects and toys remain difficult to identify on conventional radiographs of the neck and chest. Children may present with a variety of respiratory complaints, which may or may not be due to a FB. To determine whether radiolucent FBs such as plastic LEGOs and peanuts can be seen in the tracheobronchial tree or esophagus using low-dose spiral CT, and, if visible, to determine the optimal CT imaging technique. Multiple spiral sequences were performed while varying the CT parameters and the presence and location of FBs in either the trachea or the esophagus first on a neck phantom and then a cadaver. Sequences were rated by three radiologists blinded to the presence of a FB using a single scoring system. The LEGO was well visualized in the trachea by all three readers (both lung and soft-tissue windowing: combined sensitivity 89 %, combined specificity 89 %) and to a lesser extent in the esophagus (combined sensitivity 31 %, combined specificity 100 %). The peanut was not well visualized (combined sensitivity LEGO was 120 kV, 90 mA, 3-mm collimation, 0.75 s/revolution, and 2.0 pitch. This allowed for coverage of the cadaver tracheobronchial tree (approximately 11 cm) in about 18 s. Although statistical power was low for detecting significant differences, all three readers noted higher average confidence ratings with lung windowing among 18 LEGO-in-trachea scans. Rapid, low-dose spiral CT may be used to visualize LEGO FBs in the airway or esophagus. Peanuts were not well visualized.

  9. Determination of lead in clay enameled by X-ray fluorescence technique in Total reflection and by Scanning Electron Microscopy

    International Nuclear Information System (INIS)

    Zarazua O, G.; Carapia M, L.

    2000-01-01

    This work has the objective of determining lead free in the glazed commercial stewing pans using the X-ray fluorescence technique in Total reflection (FRX) and the observation and semiquantitative determination of lead by Analytical Scanning Electron Microscopy (ASEM). (Author)

  10. Investigating the Role of Global Histogram Equalization Technique for 99mTechnetium-Methylene diphosphonate Bone Scan Image Enhancement.

    Science.gov (United States)

    Pandey, Anil Kumar; Sharma, Param Dev; Dheer, Pankaj; Parida, Girish Kumar; Goyal, Harish; Patel, Chetan; Bal, Chandrashekhar; Kumar, Rakesh

    2017-01-01

    99m Technetium-methylene diphosphonate ( 99m Tc-MDP) bone scan images have limited number of counts per pixel, and hence, they have inferior image quality compared to X-rays. Theoretically, global histogram equalization (GHE) technique can improve the contrast of a given image though practical benefits of doing so have only limited acceptance. In this study, we have investigated the effect of GHE technique for 99m Tc-MDP-bone scan images. A set of 89 low contrast 99m Tc-MDP whole-body bone scan images were included in this study. These images were acquired with parallel hole collimation on Symbia E gamma camera. The images were then processed with histogram equalization technique. The image quality of input and processed images were reviewed by two nuclear medicine physicians on a 5-point scale where score of 1 is for very poor and 5 is for the best image quality. A statistical test was applied to find the significance of difference between the mean scores assigned to input and processed images. This technique improves the contrast of the images; however, oversaturation was noticed in the processed images. Student's t -test was applied, and a statistically significant difference in the input and processed image quality was found at P histogram equalization technique in combination with some other postprocessing technique is useful.

  11. 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

  12. An enhanced CCRTM (E-CCRTM) damage imaging technique using a 2D areal scan for composite plates

    Science.gov (United States)

    He, Jiaze; Yuan, Fuh-Gwo

    2016-04-01

    A two-dimensional (2-D) non-contact areal scan system was developed to image and quantify impact damage in a composite plate using an enhanced zero-lag cross-correlation reverse-time migration (E-CCRTM) technique. The system comprises a single piezoelectric actuator mounted on the composite plate and a laser Doppler vibrometer (LDV) for scanning a region to capture the scattered wavefield in the vicinity of the PZT. The proposed damage imaging technique takes into account the amplitude, phase, geometric spreading, and all of the frequency content of the Lamb waves propagating in the plate; thus, the reflectivity coefficients of the delamination can be calculated and potentially related to damage severity. Comparisons are made in terms of damage imaging quality between 2-D areal scans and linear scans as well as between the proposed and existing imaging conditions. The experimental results show that the 2-D E-CCRTM performs robustly when imaging and quantifying impact damage in large-scale composites using a single PZT actuator with a nearby areal scan using LDV.

  13. 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.

  14. Characterization of the host response to the myxosporean parasite, Ceratomyxa shasta (Noble), by histology, scanning electron microscopy, and immunological techniques

    Science.gov (United States)

    Bartholomew, J.L.; Smith, C.E.; Rohovec, J.S.; Fryer, J.L.

    1989-01-01

    The tissue response of Salmo gairdneri Richardson, against the myxosporean parasite. Ceratomyxa shasta (Noble), was investigated using histological techniques, scanning electron microscopy and immunological methods. The progress of infection in C. shasta-susceptible and resistant steelhead and rainbow trout was examined by standard histological techniques and by indirect fluorescent antibody methods using monoclonal antibodies directed against C. shasta antigens. Trophozoite stages were first observed in the posterior intestine and there was indication that resistance was due to the inability of the parasite to penetrate this tissue rather than to an inflammatory response. Examination of a severely infected intestine by scanning electron microscopy showed extensive destruction of the mucosal folds of the posterior intestine. Western blotting and indirect fluorescent antibody techniques were used to investigate the immunological component of the host response. No antibodies specific for C. shasta were detected by either method.

  15. 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.

  16. 3D laser scanning techniques applying to tunnel documentation and geological mapping at Aespoe hard rock laboratory, Sweden

    International Nuclear Information System (INIS)

    Feng, Q.; Wang, G.; Roeshoff, K.

    2008-01-01

    3D terrestrial laser scanning is nowadays one of the most attractive methods to applying for 3D mapping and documentation of rock faces and tunnels, and shows the most potential to improve the data quality and provide some good solutions in rock engineering projects. In this paper, the state-of-the-art methods are described for different possibility to tunnel documentation and geological mapping based on 3D laser scanning data. Some results are presented from the case study performed at the Hard Rock Laboratory, Aespoe run by SKB, Swedish Nuclear Fuel and Waste Management Co. Comparing to traditional methods, 3D laser scanning techniques can not only provide us with a rapid and 3D digital way for tunnel documentation, but also create a potential chance to achieve high quality data, which might be beneficial to different rock engineering project procedures, including field data acquisition, data processing, data retrieving and management, and also modeling and design. (authors)

  17. Protocol for chromosome-specific probe construction using PRINS, micromanipulation and DOP-PCR techniques

    Directory of Open Access Journals (Sweden)

    PAULO Z. PASSAMANI

    2017-12-01

    Full Text Available ABSTRACT Chromosome-specific probes have been widely used in molecular cytogenetics, being obtained with different methods. In this study, a reproducible protocol for construction of chromosome-specific probes is proposed which associates in situ amplification (PRINS, micromanipulation and degenerate oligonucleotide-primed PCR (DOP-PCR. Human lymphocyte cultures were used to obtain metaphases from male and female individuals. The chromosomes were amplified via PRINS, and subcentromeric fragments of the X chromosome were microdissected using microneedles coupled to a phase contrast microscope. The fragments were amplified by DOP-PCR and labeled with tetramethyl-rhodamine-5-dUTP. The probes were used in fluorescent in situ hybridization (FISH procedure to highlight these specific regions in the metaphases. The results show one fluorescent red spot in male and two in female X chromosomes and interphase nuclei.

  18. Thin Cu film resistivity using four probe techniques: Effect of film thickness and geometrical shapes

    Science.gov (United States)

    Choudhary, Sumita; Narula, Rahul; Gangopadhyay, Subhashis

    2018-05-01

    Precise measurement of electrical sheet resistance and resistivity of metallic thin Cu films may play a significant role in temperature sensing by means of resistivity changes which can further act as a safety measure of various electronic devices during their operation. Four point probes resistivity measurement is a useful approach as it successfully excludes the contact resistance between the probes and film surface of the sample. Although, the resistivity of bulk samples at a particular temperature mostly depends on its materialistic property, however, it may significantly differ in the case of thin films, where the shape and thickness of the sample can significantly influence on it. Depending on the ratio of the film thickness to probe spacing, samples are usually classified in two segments such as (i) thick films or (ii) thin films. Accordingly, the geometric correction factors G can be related to the sample resistivity r, which has been calculated here for thin Cu films of thickness up to few 100 nm. In this study, various rectangular shapes of thin Cu films have been used to determine the shape induced geometric correction factors G. An expressions for G have been obtained as a function of film thickness t versus the probe spacing s. Using these expressions, the correction factors have been plotted separately for each cases as a function of (a) film thickness for fixed linear probe spacing and (b) probe distance from the edge of the film surface for particular thickness. Finally, we compare the experimental results of thin Cu films of various rectangular geometries with the theoretical reported results.

  19. Split bolus technique in polytrauma: a prospective study on scan protocols for trauma analysis

    NARCIS (Netherlands)

    Beenen, Ludo F. M.; Sierink, Joanne C.; Kolkman, Saskia; Nio, C. Yung; Saltzherr, Teun Peter; Dijkgraaf, Marcel G. W.; Goslings, J. Carel

    2015-01-01

    For the evaluation of severely injured trauma patients a variety of total body computed tomography (CT) scanning protocols exist. Frequently multiple pass protocols are used. A split bolus contrast protocol can reduce the number of passes through the body, and thereby radiation exposure, in this

  20. Background Noise Removal in Ultrasonic B-scan Images Using Iterative Statistical Techniques

    NARCIS (Netherlands)

    Wells, I.; Charlton, P. C.; Mosey, S.; Donne, K. E.

    2008-01-01

    The interpretation of ultrasonic B-scan images can be a time-consuming process and its success depends on operator skills and experience. Removal of the image background will potentially improve its quality and hence improve operator diagnosis. An automatic background noise removal algorithm is

  1. 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

  2. Monte Carlo simulation for scanning technique with scattering foil free electron beam: A proof of concept study.

    Directory of Open Access Journals (Sweden)

    Wonmo Sung

    Full Text Available This study investigated the potential of a newly proposed scattering foil free (SFF electron beam scanning technique for the treatment of skin cancer on the irregular patient surfaces using Monte Carlo (MC simulation. After benchmarking of the MC simulations, we removed the scattering foil to generate SFF electron beams. Cylindrical and spherical phantoms with 1 cm boluses were generated and the target volume was defined from the surface to 5 mm depth. The SFF scanning technique with 6 MeV electrons was simulated using those phantoms. For comparison, volumetric modulated arc therapy (VMAT plans were also generated with two full arcs and 6 MV photon beams. When the scanning resolution resulted in a larger separation between beams than the field size, the plan qualities were worsened. In the cylindrical phantom with a radius of 10 cm, the conformity indices, homogeneity indices and body mean doses of the SFF plans (scanning resolution = 1° vs. VMAT plans were 1.04 vs. 1.54, 1.10 vs. 1.12 and 5 Gy vs. 14 Gy, respectively. Those of the spherical phantom were 1.04 vs. 1.83, 1.08 vs. 1.09 and 7 Gy vs. 26 Gy, respectively. The proposed SFF plans showed superior dose distributions compared to the VMAT plans.

  3. Monte Carlo simulation for scanning technique with scattering foil free electron beam: A proof of concept study.

    Science.gov (United States)

    Sung, Wonmo; Park, Jong In; Kim, Jung-In; Carlson, Joel; Ye, Sung-Joon; Park, Jong Min

    2017-01-01

    This study investigated the potential of a newly proposed scattering foil free (SFF) electron beam scanning technique for the treatment of skin cancer on the irregular patient surfaces using Monte Carlo (MC) simulation. After benchmarking of the MC simulations, we removed the scattering foil to generate SFF electron beams. Cylindrical and spherical phantoms with 1 cm boluses were generated and the target volume was defined from the surface to 5 mm depth. The SFF scanning technique with 6 MeV electrons was simulated using those phantoms. For comparison, volumetric modulated arc therapy (VMAT) plans were also generated with two full arcs and 6 MV photon beams. When the scanning resolution resulted in a larger separation between beams than the field size, the plan qualities were worsened. In the cylindrical phantom with a radius of 10 cm, the conformity indices, homogeneity indices and body mean doses of the SFF plans (scanning resolution = 1°) vs. VMAT plans were 1.04 vs. 1.54, 1.10 vs. 1.12 and 5 Gy vs. 14 Gy, respectively. Those of the spherical phantom were 1.04 vs. 1.83, 1.08 vs. 1.09 and 7 Gy vs. 26 Gy, respectively. The proposed SFF plans showed superior dose distributions compared to the VMAT plans.

  4. WormScan: a technique for high-throughput phenotypic analysis of Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Mark D Mathew

    Full Text Available BACKGROUND: There are four main phenotypes that are assessed in whole organism studies of Caenorhabditis elegans; mortality, movement, fecundity and size. Procedures have been developed that focus on the digital analysis of some, but not all of these phenotypes and may be limited by expense and limited throughput. We have developed WormScan, an automated image acquisition system that allows quantitative analysis of each of these four phenotypes on standard NGM plates seeded with E. coli. This system is very easy to implement and has the capacity to be used in high-throughput analysis. METHODOLOGY/PRINCIPAL FINDINGS: Our system employs a readily available consumer grade flatbed scanner. The method uses light stimulus from the scanner rather than physical stimulus to induce movement. With two sequential scans it is possible to quantify the induced phototactic response. To demonstrate the utility of the method, we measured the phenotypic response of C. elegans to phosphine gas exposure. We found that stimulation of movement by the light of the scanner was equivalent to physical stimulation for the determination of mortality. WormScan also provided a quantitative assessment of health for the survivors. Habituation from light stimulation of continuous scans was similar to habituation caused by physical stimulus. CONCLUSIONS/SIGNIFICANCE: There are existing systems for the automated phenotypic data collection of C. elegans. The specific advantages of our method over existing systems are high-throughput assessment of a greater range of phenotypic endpoints including determination of mortality and quantification of the mobility of survivors. Our system is also inexpensive and very easy to implement. Even though we have focused on demonstrating the usefulness of WormScan in toxicology, it can be used in a wide range of additional C. elegans studies including lifespan determination, development, pathology and behavior. Moreover, we have even adapted the

  5. Non-Linear Optical Studies On Sol-Gel Derived Lead Chloride Crystals Using Z-Scan Technique

    OpenAIRE

    Rejeena, I; Lillibai, B; Toms, Roseleena; Nampoori, VP N; Radhakrishnan, P

    2014-01-01

    In this paper we report the preparation, optical characterization and non linear optical behavior of pure lead chloride crystals. Lead chloride samples subjected to UV and IR irradiation and electric and magnetic fields have also been investigated Optical nonlinearity in these lead chloride samples were determined using single beam and high sensitive Z-scan technique. Non linear optical studies of these materials in single distilled water show reverse saturable absorption which makes th...

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. A new technique for the calibration of neutron probes by volumetric method

    International Nuclear Information System (INIS)

    Encarnacao, F.A.F. da.

    1988-01-01

    Laboratory and field studies were performed for the determination of a calibration curve of a neutron probe in three different kinds of soils: Red Yellow PODZOLIC, LITOLIC and ALLUVIAL, in the last one laboratory studies were done to determine local humidity on the calibration curve parameters. (A.C.A.S.) [pt

  13. The measurements of water flow rates in the straight microchannel based on the scanning micro-PIV technique

    Science.gov (United States)

    Wang, H. L.; Han, W.; Xu, M.

    2011-12-01

    Measurement of the water flow rate in microchannel has been one of the hottest points in the applications of microfluidics, medical, biological, chemical analyses and so on. In this study, the scanning microscale particle image velocimetry (scanning micro-PIV) technique is used for the measurements of water flow rates in a straight microchannel of 200μm width and 60μm depth under the standard flow rates ranging from 2.481μL/min to 8.269μL/min. The main effort of this measurement technique is to obtain three-dimensional velocity distribution on the cross sections of microchannel by measuring velocities of the different fluid layers along the out-of-plane direction in the microchannel, so the water flow rates can be evaluated from the discrete surface integral of velocities on the cross section. At the same time, the three-dimensional velocity fields in the measured microchannel are simulated numerically using the FLUENT software in order to verify the velocity accuracy of measurement results. The results show that the experimental values of flow rates are well consistent to the standard flow rates input by the syringe pump and the compared results between numerical simulation and experiment are consistent fundamentally. This study indicates that the micro-flow rate evaluated from three-dimensional velocity by the scanning micro-PIV technique is a promising method for the micro-flow rate research.

  14. 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

  15. Spin-filter scanning tunneling microscopy : a novel technique for the analysis of spin polarization on magnetic surfaces and spintronic devices

    NARCIS (Netherlands)

    Vera Marun, I.J.

    2010-01-01

    This thesis deals with the development of a versatile technique to measure spin polarization with atomic resolution. A microscopy technique that can measure electronic spin polarization is relevant for characterization of magnetic nanostructures and spintronic devices. Scanning tunneling microscopy

  16. Development of fast parallel multi-technique scanning X-ray imaging at Synchrotron Soleil

    Science.gov (United States)

    Medjoubi, K.; Leclercq, N.; Langlois, F.; Buteau, A.; Lé, S.; Poirier, S.; Mercère, P.; Kewish, C. M.; Somogyi, A.

    2013-10-01

    A fast multimodal scanning X-ray imaging scheme is prototyped at Soleil Synchrotron. It permits the simultaneous acquisition of complementary information on the sample structure, composition and chemistry by measuring transmission, differential phase contrast, small-angle scattering, and X-ray fluorescence by dedicated detectors with ms dwell time per pixel. The results of the proof of principle experiments are presented in this paper.

  17. 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.

  18. 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.

  19. Novel low-dose imaging technique for characterizing atomic structures through scanning transmission electron microscope

    Science.gov (United States)

    Su, Chia-Ping; Syu, Wei-Jhe; Hsiao, Chien-Nan; Lai, Ping-Shan; Chen, Chien-Chun

    2017-08-01

    To investigate dislocations or heterostructures across interfaces is now of great interest to condensed matter and materials scientists. With the advances in aberration-corrected electron optics, the scanning transmission electron microscope has demonstrated its excellent capability of characterizing atomic structures within nanomaterials, and well-resolved atomic-resolution images can be obtained through long-exposure data acquisition. However, the sample drifting, carbon contamination, and radiation damage hinder further analysis, such as deriving three-dimensional (3D) structures from a series of images. In this study, a method for obtaining atomic-resolution images with significantly reduced exposure time was developed, using which an original high-resolution image with approximately one tenth the electron dose can be obtained by combining a fast-scan high-magnification image and a slow-scan low-magnification image. The feasibility of obtaining 3D atomic structures using the proposed approach was demonstrated through multislice simulation. Finally, the feasibility and accuracy of image restoration were experimentally verified. This general method cannot only apply to electron microscopy but also benefit to image radiation-sensitive materials using various light sources.

  20. Electrical impedance scanning - application of this new technique for lymph node evaluation in children

    Energy Technology Data Exchange (ETDEWEB)

    Mentzel, Hans-Joachim; Malich, Ansgar; Freesmeyer, Martin; Boettcher, Joachim; Vogt, Susanna; Kaiser, Werner A. [Institute of Diagnostic and Interventional Radiology, University of Jena, Bachstrasse 18, 07740 Jena (Germany); Kentouche, Karim; Gruhn, Bernd; Zintl, Felix [Department of Pediatrics, University of Jena, Jena (Germany); Schneider, Gerlind [Department of Otorhinolaryngology, University of Jena, Jena (Germany); Anderson, Roselle [Siemens-Elema, Elema (Sweden)

    2003-07-01

    Precise assessment of lymph nodes is crucial to the choice of therapy and prediction of outcome in cases of malignancy. Electrical impedance scanning (EIS) is being experimentally investigated for potential use as a diagnostic tool for differentiation of malignant lesions. Malignancies show different electrical properties with changes in conductivity and capacitance that can be analysed by EIS. Using a TransScan TS-2000 (TransScan Medical, Migdal Ha'Emek, Israel, distributed by Siemens-Elema AB, Solna, Sweden), EIS has been used in various studies for the identification of breast cancer as well as for characterisation of superficial lesions. To evaluate the reliability of EIS for classifying lymph nodes in a pediatric population with sonographically suspicious lesions and to prove its accuracy. The study population consisted of 77 children (42 boys, 35 girls) aged 1.1-17.1 years. All EIS results were compared to either histopathological findings or long-term follow-up investigations. Sensitivity for malignancies using EIS was 75% and specificity was 87%. The negative predictive value was 93% and the positive predictive value was 60%. This study suggests the potential usefulness of EIS as an additional imaging modality for the differentiation of lymph-node diseases in children. The histopatholgical spectrum of malignant lymph node transformation in children compared to studies in adults, and the characteristic meltdown in inflammatory or granulomatous transformed nodes, pose challenges to differentiation based on sonographic evaluation, and also to EIS classification. (orig.)

  1. Preoperative and Postoperative CT Scan Assessment of Pterygomaxillary Junction in Patients Undergoing Le Fort I Osteotomy: Comparison of Pterygomaxillary Dysjunction Technique and Trimble Technique-A Pilot Study.

    Science.gov (United States)

    Dadwal, Himani; Shanmugasundaram, S; Krishnakumar Raja, V B

    2015-09-01

    To determine the rate of complications and occurrence of pterygoid plate fractures comparing two techniques of Le Fort I osteotomy i.e., Classic Pterygomaxillary Dysjunction technique and Trimble technique and to know whether the dimensions of pterygomaxillary junction [determined preoperatively by computed tomography (CT) scan] have any influence on pterygomaxillary separation achieved during surgery. The study group consisted of eight South Indian patients with maxillary excess. A total of 16 sides were examined by CT. Preoperative CT was analyzed for all the patients. The thickness and width of the pterygomaxillary junction and the distance of the greater palatine canal from the pterygomaxillary junction was noted. Pterygomaxillary dysjunction was achieved by two techniques, the classic pterygomaxillary dysjunction technique (Group I) and Trimble technique (Group II). Patients were selected randomly and equally for both the techniques. Dysjunction was analyzed by postoperative CT. The average thickness of the pterygomaxillary junction on 16 sides was 4.5 ± 1.2 mm. Untoward pterygoid plate fractures occurred in Group I in 3 sides out of 8. In Trimble technique (Group II), no pterygoid plate fractures were noted. The average width of the pterygomaxillary junction was 7.8 ± 1.5 mm, distance of the greater palatine canal from pterygomaxillary junction was 7.4 ± 1.6 mm and the length of fusion of pterygomaxillary junction was 8.0 ± 1.9 mm. The Le Fort I osteotomy has become a standard procedure for correcting various dentofacial deformities. In an attempt to make Le Fort I osteotomy safer and avoid the problems associated with sectioning with an osteotome between the maxillary tuberosity and the pterygoid plates, Trimble suggested sectioning across the posterior aspect of the maxillary tuberosity itself. In our study, comparison between the classic pterygomaxillary dysjunction technique and the Trimble technique was made by using postoperative CT scan

  2. PINPIN a-Si:H based structures for X-ray image detection using the laser scanning technique

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, M., E-mail: mfernandes@isel.pt [Electronics Telecommunication and Computer Dept., ISEL, R.Conselheiro Emídio Navarro, 1959-007 Lisboa (Portugal); CTS-UNINOVA Quinta da Torre, Monte da Caparica, 2829-516 Caparica (Portugal); Vygranenko, Y.; Vieira, M. [Electronics Telecommunication and Computer Dept., ISEL, R.Conselheiro Emídio Navarro, 1959-007 Lisboa (Portugal); CTS-UNINOVA Quinta da Torre, Monte da Caparica, 2829-516 Caparica (Portugal)

    2015-05-01

    Highlights: • We present novel structure for X-ray image sensor based on the laser scanned technique. • Amorphous silicon based tandem structure characterization results are presented and discussed. • Results from preliminary tests of the imaging application are promising for very large area image sensing. - Abstract: Conventional film based X-ray imaging systems are being replaced by their digital equivalents. Different approaches are being followed by considering direct or indirect conversion, with the later technique dominating. The typical, indirect conversion, X-ray panel detector uses a phosphor for X-ray conversion coupled to a large area array of amorphous silicon based optical sensors and a couple of switching thin film transistors (TFT). The pixel information can then be readout by switching the correspondent line and column transistors, routing the signal to an external amplifier. In this work we follow an alternative approach, where the electrical switching performed by the TFT is replaced by optical scanning using a low power laser beam and a sensing/switching PINPIN structure, thus resulting in a simpler device. The optically active device is a PINPIN array, sharing both front and back electrical contacts, deposited over a glass substrate. During X-ray exposure, each sensing side photodiode collects photons generated by the scintillator screen (560 nm), charging its internal capacitance. Subsequently a laser beam (445 nm) scans the switching diodes (back side) retrieving the stored charge in a sequential way, reconstructing the image. In this paper we present recent work on the optoelectronic characterization of the PINPIN structure to be incorporated in the X-ray image sensor. The results from the optoelectronic characterization of the device and the dependence on scanning beam parameters are presented and discussed. Preliminary results of line scans are also presented.

  3. Practical aspects of spherical near-field antenna measurements using a high-order probe

    DEFF Research Database (Denmark)

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

    2006-01-01

    Two practical aspects related to accurate antenna pattern characterization by probe-corrected spherical near-field antenna measurements with a high-order probe are examined. First, the requirements set by an arbitrary high-order probe on the scanning technique are pointed out. Secondly, a channel...... balance calibration procedure for a high-order dual-port probe with non-identical ports is presented, and the requirements set by this procedure for the probe are discussed....

  4. 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.

  5. Application of the multisphere technique. Calibration and use of a modified Multiple Probe Detector

    International Nuclear Information System (INIS)

    Lalande, R.

    1966-11-01

    The study concerns the search for a portable, compact device with a great autonomy of operation, able to carry out precise measurements of fast neutrons in exclusion zones. A DSM-type multi-probe detector, which is self-contained and fully transistorized, have been studied; it includes a storage battery with a 30 hour autonomy and a buffering capability, a pulse amplifier, an integrator (sensitivity 4 c / s - 200 c / s - 2000 c / s), a totalizer to carry out counting on 5 mm, and a SNR fast neutron probe equipped with its preamplifier. Slightly modified, this device perfectly fulfills the operating conditions. Designed to precisely define the relationship between the flow and the dose intensity, it allows to calibrate any type of fast neutrons detector (e.g. BF 3 or unmodified DSM) that will respond correctly and will provide routine monitoring at a facility

  6. Probing Enzyme-Surface Interactions via Protein Engineering and Single-Molecule Techniques

    Science.gov (United States)

    2017-06-26

    SECURITY CLASSIFICATION OF: The overall objective of this research was to exploit protein engineering and fluorescence single-molecule methods to...enhance our understanding of the interaction of proteins and surfaces. Given this objective, the specific aims of this research were to: 1) exploit the...incorporation of unnatural amino acids in proteins to introduce single-molecule probes (i.e., fluorophores for fluorescence resonance energy transfer

  7. An Eddy Current Testing Platform System for Pipe Defect Inspection Based on an Optimized Eddy Current Technique Probe Design

    Science.gov (United States)

    Rifai, Damhuji; Abdalla, Ahmed N.; Razali, Ramdan; Ali, Kharudin; Faraj, Moneer A.

    2017-01-01

    The use of the eddy current technique (ECT) for the non-destructive testing of conducting materials has become increasingly important in the past few years. The use of the non-destructive ECT plays a key role in the ensuring the safety and integrity of the large industrial structures such as oil and gas pipelines. This paper introduce a novel ECT probe design integrated with the distributed ECT inspection system (DSECT) use for crack inspection on inner ferromagnetic pipes. The system consists of an array of giant magneto-resistive (GMR) sensors, a pneumatic system, a rotating magnetic field excitation source and a host PC acting as the data analysis center. Probe design parameters, namely probe diameter, an excitation coil and the number of GMR sensors in the array sensor is optimized using numerical optimization based on the desirability approach. The main benefits of DSECT can be seen in terms of its modularity and flexibility for the use of different types of magnetic transducers/sensors, and signals of a different nature with either digital or analog outputs, making it suited for the ECT probe design using an array of GMR magnetic sensors. A real-time application of the DSECT distributed system for ECT inspection can be exploited for the inspection of 70 mm carbon steel pipe. In order to predict the axial and circumference defect detection, a mathematical model is developed based on the technique known as response surface methodology (RSM). The inspection results of a carbon steel pipe sample with artificial defects indicate that the system design is highly efficient. PMID:28335399

  8. Study of plasma-material surface interaction using Langmuir probe technique during plasma treatment

    International Nuclear Information System (INIS)

    Saloum, S.; Akel, M.

    2009-06-01

    In this study, we tried to understand the plasma-surface interactions by using Langmuir probes. Two different types of plasmas were studied, the first is the electropositive plasma in Argon and the second is the electronegative plasma in Sulfur Hexafluoride. In the first type, the effects of Argon gas pressure, the injection of Helium in the remote zone and the substrate bias on the measurements of the Electron Energy Probability Function (EEPF) and on the plasma parameters (electron density (n e ), effective electron temperature (T e ff), plasma potential (V p ) and floating potential (V f )) have been investigated. The obtained EEPFs and plasma parameters have been used to control two remote plasma processes. The first is the remote Plasma Enhanced Chemical Vapor Deposition (PE-CVD) of thin films, on silicon wafers, from Hexamethyldisoloxane (HMDSO) precursor diluted in the remote Ar-He plasma. The second is the pure Argon remote plasma treatment of polymethylmethacrylate (PMMA) polymer surface. In the second type, the plasma diagnostics were performed in the remote zone as a function of SF 6 flow rate, where relative concentrations of fluorine atoms were measured using actinometry optical emission spectroscopy; electron density, electron temperature and plasma potential were determined using single cylindrical Langmuir probe, positive ion flux and negative ion fraction were determined using an planar probe. The silicon etching process in SF 6 plasma was studied. (author)

  9. Study of plasma-material surface interaction using langmuir probe technique during plasma treatment

    International Nuclear Information System (INIS)

    Saloum, S.; Akel, M.

    2012-01-01

    In this study, we tried to understand the plasma-surface interactions by using Langmuir probes. Two different types of plasmas were studied, the first is the electropositive plasma in Argon and the second is the electronegative plasma in Sulfur Hexafluoride. In the first type, the effects of Argon gas pressure, the injection of Helium in the remote zone and the substrate bias on the measurements of the Electron Energy Probability Function (EEPF) and on the plasma parameters (electron density (n e ), effective electron temperature (T e ff), plasma potential (V p ) and floating potential (V f )) have been investigated. The obtained EEPFs and plasma parameters have been used to control two remote plasma processes. The first is the remote Plasma Enhanced Chemical Vapor Deposition (PE-CVD) of thin films, on silicon wafers, from Hexamethyldisiloxane (HMDSO) precursor diluted in the remote Ar-He plasma. The second is the pure Argon remote plasma treatment of polymethylmethacrylate (PMMA) polymer surface. In the second type, the plasma diagnostics were performed in the remote zone as a function of SF 6 flow rate, where relative concentrations of fluorine atoms were measured using actinometry optical emission spectroscopy; electron density, electron temperature and plasma potential were determined using single cylindrical Langmuir probe, positive ion flux and negative ion fraction were determined using an planar probe. The silicon etching process in SF 6 plasma was studied. (author)

  10. Generation of 3D Virtual Geographic Environment Based on Laser Scanning Technique

    Institute of Scientific and Technical Information of China (English)

    DU Jie; CHEN Xiaoyong; FumioYamazaki

    2003-01-01

    This paper demonstrates an experiment on the generation of 3D virtual geographic environment on the basis of experimental flight laser scanning data by a set of algorithms and methods that were developed to automatically interpret range images for extracting geo-spatial features and then to reconstruct geo-objects. The algorithms and methods for the interpretation and modeling of laser scanner data include triangulated-irregular-network (TIN)-based range image interpolation ; mathematical-morphology(MM)-based range image filtering,feature extraction and range image segmentation, feature generalization and optimization, 3D objects reconstruction and modeling; computergraphics (CG)-based visualization and animation of geographic virtual reality environment.

  11. Scanning ion micro-beam techniques for measuring diffusion in heterogeneous materials

    International Nuclear Information System (INIS)

    Jenneson, P.M.; Clough, A.S.

    1998-01-01

    A raster scanning MeV micro-beam of 1 H + or 3 He + ions was used to study the diffusion of small molecules in heterogeneous materials. The location of elemental contaminants (heavier than Lithium) in polymer insulated cables was studied with 1 H micro-Particle Induced X-ray Emission (μPIXE). Concentration profiles of a deuterated molecule in a hair fibre were determined with 3 He micro-Nuclear Reaction Analysis (μNRA). Chlorine and heavy water (D 2 0) diffusion into cement pastes were profiled using a combination of 3 He μPIXE and μNRA. (authors)

  12. Accuracy in estimation of timber assortments and stem distribution - A comparison of airborne and terrestrial laser scanning techniques

    Science.gov (United States)

    Kankare, Ville; Vauhkonen, Jari; Tanhuanpää, Topi; Holopainen, Markus; Vastaranta, Mikko; Joensuu, Marianna; Krooks, Anssi; Hyyppä, Juha; Hyyppä, Hannu; Alho, Petteri; Viitala, Risto

    2014-11-01

    Detailed information about timber assortments and diameter distributions is required in forest management. Forest owners can make better decisions concerning the timing of timber sales and forest companies can utilize more detailed information to optimize their wood supply chain from forest to factory. The objective here was to compare the accuracies of high-density laser scanning techniques for the estimation of tree-level diameter distribution and timber assortments. We also introduce a method that utilizes a combination of airborne and terrestrial laser scanning in timber assortment estimation. The study was conducted in Evo, Finland. Harvester measurements were used as a reference for 144 trees within a single clear-cut stand. The results showed that accurate tree-level timber assortments and diameter distributions can be obtained, using terrestrial laser scanning (TLS) or a combination of TLS and airborne laser scanning (ALS). Saw log volumes were estimated with higher accuracy than pulpwood volumes. The saw log volumes were estimated with relative root-mean-squared errors of 17.5% and 16.8% with TLS and a combination of TLS and ALS, respectively. The respective accuracies for pulpwood were 60.1% and 59.3%. The differences in the bucking method used also caused some large errors. In addition, tree quality factors highly affected the bucking accuracy, especially with pulpwood volume.

  13. Technique for evaluation of spatial resolution and microcalcifications in digital and scanned images of a standard breast phantom

    International Nuclear Information System (INIS)

    Santana, Priscila do C.; Gomes, Danielle S.; Oliveira, Marcio A.; Oliveira, Paulo Marcio C. de; Meira-Belo, Luiz C.; Nogueira-Tavares, Maria S.

    2011-01-01

    In this work, an automated methodology to evaluate digital and scanned images of a standard phantom (Phantom Mama) was studied. The Phantom Mama was used as an important tool to check the quality of mammographs. The scanned images were digitized using a ScanMaker 9800XL, with resolution of 900 dpi. The aim of this work is to test an automatic methodology for evaluation of spatial resolution and microcalcifications group of phantom mama images acquired with the same parameters in the same equipment. In order to analyze the images we have used the ImageJ software (in Java) which is public domain. We have used the Fast Fourier transform technique to evaluate the spatial resolution and used the ImageJ function Subtract Background and the Light Background plus Sliding Paraboloid on the evaluation of the five groups of microcalcifications on the breast phantom to assess the viability of using automated methods for both types of images. The methodology was adequate for evaluated the microcalcifications group and the spatial resolution in scanned and digital images, but the Phantom Mama doesn't provide sufficient parameters to evaluate the spatial resolution in this images. (author)

  14. PINPIN a-Si:H based structures for X-ray image detection using the laser scanning technique

    Science.gov (United States)

    Fernandes, M.; Vygranenko, Y.; Vieira, M.

    2015-05-01

    Conventional film based X-ray imaging systems are being replaced by their digital equivalents. Different approaches are being followed by considering direct or indirect conversion, with the later technique dominating. The typical, indirect conversion, X-ray panel detector uses a phosphor for X-ray conversion coupled to a large area array of amorphous silicon based optical sensors and a couple of switching thin film transistors (TFT). The pixel information can then be readout by switching the correspondent line and column transistors, routing the signal to an external amplifier. In this work we follow an alternative approach, where the electrical switching performed by the TFT is replaced by optical scanning using a low power laser beam and a sensing/switching PINPIN structure, thus resulting in a simpler device. The optically active device is a PINPIN array, sharing both front and back electrical contacts, deposited over a glass substrate. During X-ray exposure, each sensing side photodiode collects photons generated by the scintillator screen (560 nm), charging its internal capacitance. Subsequently a laser beam (445 nm) scans the switching diodes (back side) retrieving the stored charge in a sequential way, reconstructing the image. In this paper we present recent work on the optoelectronic characterization of the PINPIN structure to be incorporated in the X-ray image sensor. The results from the optoelectronic characterization of the device and the dependence on scanning beam parameters are presented and discussed. Preliminary results of line scans are also presented.

  15. Helium ion microscopy and energy selective scanning electron microscopy - two advanced microscopy techniques with complementary applications

    Science.gov (United States)

    Rodenburg, C.; Jepson, M. A. E.; Boden, Stuart A.; Bagnall, Darren M.

    2014-06-01

    Both scanning electron microscopes (SEM) and helium ion microscopes (HeIM) are based on the same principle of a charged particle beam scanning across the surface and generating secondary electrons (SEs) to form images. However, there is a pronounced difference in the energy spectra of the emitted secondary electrons emitted as result of electron or helium ion impact. We have previously presented evidence that this also translates to differences in the information depth through the analysis of dopant contrast in doped silicon structures in both SEM and HeIM. Here, it is now shown how secondary electron emission spectra (SES) and their relation to depth of origin of SE can be experimentally exploited through the use of energy filtering (EF) in low voltage SEM (LV-SEM) to access bulk information from surfaces covered by damage or contamination layers. From the current understanding of the SES in HeIM it is not expected that EF will be as effective in HeIM but an alternative that can be used for some materials to access bulk information is presented.

  16. Development of a New Radiation Measuring Instrument for the Column Scanning Technique - NibraS

    International Nuclear Information System (INIS)

    Benahmed, A.; Alami, R.

    2013-06-01

    The radiation measuring instrument, called Nibras, associated to a special data processing software for Column scanning is a new data acquisition system. It was developed to scan and to plot density profiles, inside a distillation column, which illustrates the activity of the radiations able to cross the contents of the column. Nibras is an autonomous data logger with very low power consumption, using only 4 batteries of 1.5 V and can be operated for more than 120 hours continuously; this presents an ecological and economic importance. Another particularity of Nibras consists in its dual functionality to display counting rates indicating the existence and the intensity of radiation; and to perform a real-time control in industrial plant particularly in oil distillation columns, due to its user-friendly software. This last provides essential data to optimize the performance of the columns, extend column run times, track the performance-deteriorating effects of fouling and solids deposition, and to identify maintenance requirements well in advance of scheduled turnarounds. This on-line knowledge can reduce repair downtime significantly. (authors)

  17. Application of the modulated temperature differential scanning calorimetry technique for the determination of the specific heat of copper nanofluids

    International Nuclear Information System (INIS)

    De Robertis, E.; Cosme, E.H.H.; Neves, R.S.; Kuznetsov, A.Yu.; Campos, A.P.C.; Landi, S.M.; Achete, C.A.

    2012-01-01

    The purpose of this work is to investigate the applicability of the modulated temperature differential scanning calorimetry technique to measure specific heat of copper nanofluids by using the ASTM E2719 standard procedure, which is generally applied to thermally stable solids and liquids. The one-step method of preparation of copper nanofluid samples is described. The synthesized nanoparticles were separated from the base fluid and examined by X-ray diffraction and transmission electron microscopy in order to evaluate their structure, morphology and chemical nature. The presence of copper nanoparticles in the base fluid alters the characteristics of crystallization and melting processes and reduces the specific heat values of nanofluids in the whole studied temperature range. - Highlights: ► Copper nanofluids prepared by one-step method. ► Methodology of synthesis improved nanofluid stability. ► Specific heat determinations using modulated temperature differential scanning calorimetry. ► Good agreement between theoretical and experimental values.

  18. SU-E-T-561: Development of Depth Dose Measurement Technique Using the Multilayer Ionization Chamber for Spot Scanning Method

    International Nuclear Information System (INIS)

    Takayanagi, T; Fujitaka, S; Umezawa, M; Ito, Y; Nakashima, C; Matsuda, K

    2014-01-01

    Purpose: To develop a measurement technique which suppresses the difference between profiles obtained with a multilayer ionization chamber (MLIC) and with a water phantom. Methods: The developed technique multiplies the raw MLIC data by a correction factor that depends on the initial beam range and water equivalent depth. The correction factor is derived based on a Bragg curve calculation formula considering range straggling and fluence loss caused by nuclear reactions. Furthermore, the correction factor is adjusted based on several integrated depth doses measured with a water phantom and the MLIC. The measured depth dose profiles along the central axis of the proton field with a nominal field size of 10 by 10 cm were compared between the MLIC using the new technique and the water phantom. The spread out Bragg peak was 20 cm for fields with a range of 30.6 cm and 6.9 cm. Raw MLIC data were obtained with each energy layer, and integrated after multiplying by the correction factor. The measurements were performed by a spot scanning nozzle at Nagoya Proton Therapy Center, Japan. Results: The profile measured with the MLIC using the new technique is consistent with that of the water phantom. Moreover, 97% of the points passed the 1% dose /1mm distance agreement criterion of the gamma index. Conclusion: We have demonstrated that the new technique suppresses the difference between profiles obtained with the MLIC and with the water phantom. It was concluded that this technique is useful for depth dose measurement in proton spot scanning method

  19. Holocene Temperature Reconstructions from Arctic Lakes based on Alkenone Paleothermometry and Non-Destructive Scanning Techniques

    Science.gov (United States)

    D'Andrea, W. J.; Balascio, N. L.; Bradley, R. S.; Bakke, J.; Gjerde, M.; Kaufman, D. S.; Briner, J. P.; von Gunten, L.

    2014-12-01

    Generating continuous, accurate and quantitative Holocene temperature estimates from the Arctic is an ongoing challenge. In many Arctic regions, tree ring-based approaches cannot be used and lake sediments provide the most valuable repositories for extracting paleotemperature information. Advances in lacustrine alkenone paleothermometry now allow for quantitative reconstruction of lake-water temperature based on the UK37 values of sedimentary alkenones. In addition, a recent study demonstrated the efficacy of non-destructive scanning reflectance spectroscopy in the visible range (VIS-RS) for high-resolution quantitative temperature reconstruction from arctic lake sediments1. In this presentation, I will report a new UK37-based temperature reconstruction and a scanning VIS-RS record (using the RABD660;670 index as a measure of sedimentary chlorin content) from Kulusuk Lake in southeastern Greenland (65.6°N, 37.1°W). The UK37 record reveals a ~3°C increase in summer lake water temperatures between ~10ka and ~7ka followed by sustained warmth until ~4ka and a gradual (~3°C) cooling until ~400 yr BP. The strong correlation between UK37 and RABD660;670 measured in the same sediment core provides further evidence that in arctic lakes where temperature regulates primary productivity, and thereby sedimentary chlorin content, these proxies can be combined to develop high-resolution quantitative temperature records. The Holocene temperature history of Kulusuk Lake determined using this approach corresponds to changes in the size of the glaciers adjacent to the lake, as inferred from sediment minerogenic properties measured with scanning XRF. Glaciers retreated during early Holocene warming, likely disappeared during the period of mid-Holocene warmth, and advanced after 4ka. I will also discuss new UK37 and RABD660;670 reconstructions from northwestern Svalbard and the central Brooks Range of Alaska within the framework of published regional temperature reconstructions and

  20. The rf sigmameter: A digital phase-locked technique for accurate long-range laser scanning

    International Nuclear Information System (INIS)

    Zhu, M.; Hall, J.L.

    1986-01-01

    The authors use a new version of a sigmameter, the two-channel field-widened rf sigmameter, to map optical frequency into the phase of an rf signal. This enables them to lock the laser frequency on the interferometer by using a phase-locked loop (PLL). Controlling the reference phase of the PLL electronically, they are able to scan the laser frequency over a long range step by step or with substeps. The systematic error of each substep is cancelled automatically when the authors change one step (which is ten substeps, for example), and that of each step is cancelled when they change the reference phase by 2π (which corresponds to 256 steps in their scheme)

  1. Scanning laser techniques for dynamic thermo-magnetic recording onto stationary media

    Energy Technology Data Exchange (ETDEWEB)

    Clegg, Warwick; Jenkins, David; Helian, Na; Windmill, James; Windmill, Robert; Atkinson, Ron; Hendren, Bill; Wright, C. David

    2002-09-01

    Scanning laser microscopes (SLMs) have been used to characterise the magnetic properties of materials for some time (J. Magn. Magn. Mater. 95(1) (1991); IEEE Trans. Magn. 31(6 Pt. 1) (1995)). An SLM has been designed to facilitate a number of operating modes: both for writing and reading magneto-optical data. The current SLM is capable of thermo-magnetically recording bits onto magneto-optical thin films. Unlike previous SLMs, the current instrument has been designed to write bits both statically and dynamically onto stationary media. It will be used to write to magneto-optic (MO) disk material thermo-magnetically prior to imaging. Images may be derived from the longitudinal and polar magneto-optic Kerr effects, which are wavelength dependent, using the appropriate laser wavelength. In this paper the two configurations for dynamic recording are described.

  2. Scanning laser techniques for dynamic thermo-magnetic recording onto stationary media

    International Nuclear Information System (INIS)

    Clegg, Warwick; Jenkins, David; Helian, Na; Windmill, James; Windmill, Robert; Atkinson, Ron; Hendren, Bill; Wright, C. David

    2002-01-01

    Scanning laser microscopes (SLMs) have been used to characterise the magnetic properties of materials for some time (J. Magn. Magn. Mater. 95(1) (1991); IEEE Trans. Magn. 31(6 Pt. 1) (1995)). An SLM has been designed to facilitate a number of operating modes: both for writing and reading magneto-optical data. The current SLM is capable of thermo-magnetically recording bits onto magneto-optical thin films. Unlike previous SLMs, the current instrument has been designed to write bits both statically and dynamically onto stationary media. It will be used to write to magneto-optic (MO) disk material thermo-magnetically prior to imaging. Images may be derived from the longitudinal and polar magneto-optic Kerr effects, which are wavelength dependent, using the appropriate laser wavelength. In this paper the two configurations for dynamic recording are described

  3. A low-cost technique to manufacture a container to process meiofauna for scanning electron microscopy.

    Science.gov (United States)

    Abolafia, J

    2015-09-01

    An easy and low-cost method to elaborate a container to dehydrate nematodes and other meiofauna in order to process them for scanning electron microscopy (SEM) is presented. Illustrations of its elaboration, step by step, are included. In addition, a brief methodology to process meiofauna, especially nematodes and kinorhynchs, and illustrations are provided. With this methodology it is possible to easily introduce the specimens, to lock them in a closed chamber allowing the infiltration of fluids and gases (ethanol, acetone, carbon dioxide) but avoiding losing the specimens. After using this meiofauna basket for SEM the results are efficient. Examples of nematode and kinorhynch SEM pictures obtained using this methodology are also included. © 2015 Wiley Periodicals, Inc.

  4. Application of laser scanning technique in earthquake protection of Istanbul's historical heritage buildings

    Science.gov (United States)

    Çaktı, Eser; Ercan, Tülay; Dar, Emrullah

    2017-04-01

    Istanbul's vast historical and cultural heritage is under constant threat of earthquakes. Historical records report repeated damages to the city's landmark buildings. Our efforts towards earthquake protection of several buildings in Istanbul involve earthquake monitoring via structural health monitoring systems, linear and non-linear structural modelling and analysis in search of past and future earthquake performance, shake-table testing of scaled models and non-destructive testing. More recently we have been using laser technology in monitoring structural deformations and damage in five monumental buildings which are Hagia Sophia Museum and Fatih, Sultanahmet, Süleymaniye and Mihrimah Sultan Mosques. This presentation is about these efforts with special emphasis on the use of laser scanning in monitoring of edifices.

  5. A novel approach to water polution monitoring by combining ion exchange resin and XRF-scanning technique

    Science.gov (United States)

    Huang, J. J.; Lin, S. C.; Löwemark, L.; Liou, Y. H.; Chang, Q. M.; Chang, T. K.; Wei, K. Y.; Croudace, I. W. C.

    2017-12-01

    Due to the rapid industrial expansion, environments are subject to irregular fluctuations and spatial distributions in pollutant concentrations. This study proposes to use ion exchange resin accompanied with the XRF-scanning technique to monitor environmental pollution. As a passive sampling sorbent, the use of ion exchange resin provides a rapid, low cost and simple method to detect episodic pollution signals with a high spatial sampling density. In order to digest large quantities of samples, the fast and non-destructive Itrax-XRF core scanner has been introduced to assess elemental concentrations in the resin samples. Although the XRF scanning results are often considered as a semi-quantitative measurement due to possible absorption or scattering caused by the physical variabilities of scanned materials, the use of resin can minimize such influences owing to the standarization of the sample matrix. In this study, 17 lab-prepared standard resin samples were scanned with the Itrax-XRF core scanner (at 100 s exposure time with the Mo-tube) and compared with the absolute elemental concentrations. Six elements generally used in pollution studies (Cr, Mn, Ni, Cu, Zn, and Pb) were selected, and their regression lines and correlation coefficients were determined. In addition, 5 standard resin samples were scanned at different exposure time settings (1 s, 5 s, 15 s, 30 s, 100 s) to address the influence of exposure time on the accuracy of the measurements. The results show that within the test range (from few ppm to thousands ppm), the correlation coefficients are higher than 0.97, even at the shortest exposure time (1 s). Furthermore, a pilot field survey with 30 resin samples has been conducted in a potentially polluted farm area in central Taiwan to demonstrate the feasibility of this novel approach. The polluted hot zones could be identified and the properties and sources of wastewater pollution can therefore be traced over large areas for the purposes of

  6. A new standardless quantitative electron probe microanalysis technique applied to III-V compound semiconductors

    International Nuclear Information System (INIS)

    Zangalis, K.P.; Christou, A.

    1982-01-01

    The present paper introduces a new standardless quantitative scheme for off-line electron microprobe analysis applications. The analysis is based on standard equations of the type Isub(i)=Csub(i)fsub(ZAF)βsub(i) and is specifically suitable for compound semiconductors. The roots to the resultant nth-degree polynomial are the unknown concentrations. Methods for computing Csub(i) when coefficients βsub(i) are unknown are also outlined. Applications of standardless analysis to GaAs and InP specimens are compared with results obtained by Auger electron spectroscopy and quantitative electron probe analysis with standards. (Auth.)

  7. Applying computational geometry techniques for advanced feature analysis in atom probe data

    International Nuclear Information System (INIS)

    Felfer, Peter; Ceguerra, Anna; Ringer, Simon; Cairney, Julie

    2013-01-01

    In this paper we present new methods for feature analysis in atom probe tomography data that have useful applications in materials characterisation. The analysis works on the principle of Voronoi subvolumes and piecewise linear approximations, and feature delineation based on the distance to the centre of mass of a subvolume (DCOM). Based on the coordinate systems defined by these approximations, two examples are shown of the new types of analyses that can be performed. The first is the analysis of line-like-objects (i.e. dislocations) using both proxigrams and line-excess plots. The second is interfacial excess mapping of an InGaAs quantum dot. - Highlights: • Computational geometry is used to detect and analyse features within atom probe data. • Limitations of conventional feature detection are overcome by using atomic density gradients. • 0D, 1D, 2D and 3D features can be analysed by using Voronoi tessellation for spatial binning. • New, robust analysis methods are demonstrated, including line and interfacial excess mapping

  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. Comparison of digital scanning and polyvinyl siloxane impression techniques by dental students: instructional efficiency and attitudes towards technology.

    Science.gov (United States)

    Marti, A M; Harris, B T; Metz, M J; Morton, D; Scarfe, W C; Metz, C J; Lin, W-S

    2017-08-01

    With increasing use of digital scanning with restorative procedures in the dental office, it becomes necessary that educational institutions adopt instructional methodology for introducing this technology together with conventional impression techniques. To compare the time differences between instructing dental students on digital scanning (DS) (LAVA C.O.S. digital impression system) and a conventional impression technique (CI) (polyvinyl siloxane), and to compare students' attitudes and beliefs towards both techniques. Volunteer sophomore dental students (n = 25) with no prior experience in clinical impressions were recruited and IRB consent obtained. Participants responded to a pre-and post-exposure questionnaire. Participants were instructed on the use of both DS and CI for a single tooth full coverage crown restoration using a consecutive sequence of video lecture, investigator-led demonstration and independent impression exercise. The time necessary for each step (minutes) was recorded. Statistical significance was calculated using dependent t-tests (time measurements) and 2-sample Mann-Whitney (questionnaire responses). The time spent teaching students was greater for DS than CI for video lecture (15.95 and 10.07 min, P = 0.0000), demonstration time (9.06 and 4.70 min, P = 0.0000) and impression time (18.17 and 8.59 min, P = 0.0000). Prior to the instruction and practice, students considered themselves more familiar with CI (3.96) than DS (1.96) (P = 0.0000). After the instruction and practice, participants reported CI technique proved significantly easier than expected (pre-instruction: 3.52 and post-instruction: 4.08, P = 0.002). However, overall participants' perception of ease of use for DS was not influenced by this instruction and practice experience (pre-instruction: 3.84 and post-instruction: 3.56, P = 0.106). Despite the results, 96% of participants expressed an expectation that DS will become their predominant impression technique during their

  10. An evaluation of some replication techniques for materials science applications of scanning electron microscopy

    International Nuclear Information System (INIS)

    Carpenter, G.J.C.; Baird, J.

    1976-06-01

    Several techniques for producing positive replicas for materials science applications have been critically examined: 1) Consistent high resolution replicas can be produced by vacuum evaporation of a gold film onto a 'Bioden' (cellulose acetate) negative replica, backing the film with electroplated copper and dissolving the 'Bioden'; 2) negative replicas that are easy to strip and handle may be made using a silicone rubber compound, 'Silastic' RTV 'A' but with highly variable resolution; 3) an epoxy resin, 'Ren', gave good resolution but could not easily be stripped from a specimen surface: it is therefore only suitable for the final (positive) stage of replication. Some possible techniques for obtaining more consistent resolution from 'Silastic' RTV synthetic rubbers are suggested. (author)

  11. Analytical and laser scanning techniques to determine shape properties of aggregates used in pavements

    CSIR Research Space (South Africa)

    Komba, Julius J

    2013-06-01

    Full Text Available and volume of an aggregate particle, the sphericity computed by using orthogonal dimensions of an aggregate particle, and the flat and elongated ratio computed by using longest and smallest dimensions of an aggregate particle. The second approach employed.... Further validation of the laser-based technique was achieved by correlating the laser-based aggregate form indices with the results from two current standard tests; the flakiness index and the flat and elongated particles ratio tests. The laser...

  12. 3D-Laser-Scanning Technique Applied to Bulk Density Measurements of Apollo Lunar Samples

    Science.gov (United States)

    Macke, R. J.; Kent, J. J.; Kiefer, W. S.; Britt, D. T.

    2015-01-01

    In order to better interpret gravimetric data from orbiters such as GRAIL and LRO to understand the subsurface composition and structure of the lunar crust, it is import to have a reliable database of the density and porosity of lunar materials. To this end, we have been surveying these physical properties in both lunar meteorites and Apollo lunar samples. To measure porosity, both grain density and bulk density are required. For bulk density, our group has historically utilized sub-mm bead immersion techniques extensively, though several factors have made this technique problematic for our work with Apollo samples. Samples allocated for measurement are often smaller than optimal for the technique, leading to large error bars. Also, for some samples we were required to use pure alumina beads instead of our usual glass beads. The alumina beads were subject to undesirable static effects, producing unreliable results. Other investigators have tested the use of 3d laser scanners on meteorites for measuring bulk volumes. Early work, though promising, was plagued with difficulties including poor response on dark or reflective surfaces, difficulty reproducing sharp edges, and large processing time for producing shape models. Due to progress in technology, however, laser scanners have improved considerably in recent years. We tested this technique on 27 lunar samples in the Apollo collection using a scanner at NASA Johnson Space Center. We found it to be reliable and more precise than beads, with the added benefit that it involves no direct contact with the sample, enabling the study of particularly friable samples for which bead immersion is not possible

  13. Laser Scanning Systems and Techniques in Rockfall Source Identification and Risk Assessment: A Critical Review

    Science.gov (United States)

    Fanos, Ali Mutar; Pradhan, Biswajeet

    2018-04-01

    Rockfall poses risk to people, their properties and to transportation ways in mountainous and hilly regions. This catastrophe shows various characteristics such as vast distribution, sudden occurrence, variable magnitude, strong fatalness and randomicity. Therefore, prediction of rockfall phenomenon both spatially and temporally is a challenging task. Digital Terrain model (DTM) is one of the most significant elements in rockfall source identification and risk assessment. Light detection and ranging (LiDAR) is the most advanced effective technique to derive high-resolution and accurate DTM. This paper presents a critical overview of rockfall phenomenon (definition, triggering factors, motion modes and modeling) and LiDAR technique in terms of data pre-processing, DTM generation and the factors that can be obtained from this technique for rockfall source identification and risk assessment. It also reviews the existing methods that are utilized for the evaluation of the rockfall trajectories and their characteristics (frequency, velocity, bouncing height and kinetic energy), probability, susceptibility, hazard and risk. Detail consideration is given on quantitative methodologies in addition to the qualitative ones. Various methods are demonstrated with respect to their application scales (local and regional). Additionally, attention is given to the latest improvement, particularly including the consideration of the intensity of the phenomena and the magnitude of the events at chosen sites.

  14. Switching Transient Generation in Surface Interrogation Scanning Electrochemical Microscopy and Time-of-Flight Techniques.

    Science.gov (United States)

    Ahn, Hyun S; Bard, Allen J

    2015-12-15

    In surface interrogation scanning electrochemical microscopy (SI-SECM), fine and accurate control of the delay time between substrate generation and tip interrogation (tdelay) is crucial because tdelay defines the decay time of the reactive intermediate. In previous applications of the SI-SECM, the resolution in the control of tdelay has been limited to several hundreds of milliseconds due to the slow switching of the bipotentiostat. In this work, we have improved the time resolution of tdelay control up to ca. 1 μs, enhancing the SI-SECM to be competitive in the time domain with the decay of many reactive intermediates. The rapid switching SI-SECM has been implemented in a substrate generation-tip collection time-of-flight (SG-TC TOF) experiment of a solution redox mediator, and the results obtained from the experiment exhibited good agreement with that obtained from digital simulation. The reaction rate constant of surface Co(IV) on oxygen-evolving catalyst film, which was inaccessible thus far due to the lack of tdelay control, has been measured by the rapid switching SI-SECM.

  15. Optimizing the 3D-reconstruction technique for serial block-face scanning electron microscopy.

    Science.gov (United States)

    Wernitznig, Stefan; Sele, Mariella; Urschler, Martin; Zankel, Armin; Pölt, Peter; Rind, F Claire; Leitinger, Gerd

    2016-05-01

    Elucidating the anatomy of neuronal circuits and localizing the synaptic connections between neurons, can give us important insights in how the neuronal circuits work. We are using serial block-face scanning electron microscopy (SBEM) to investigate the anatomy of a collision detection circuit including the Lobula Giant Movement Detector (LGMD) neuron in the locust, Locusta migratoria. For this, thousands of serial electron micrographs are produced that allow us to trace the neuronal branching pattern. The reconstruction of neurons was previously done manually by drawing cell outlines of each cell in each image separately. This approach was very time consuming and troublesome. To make the process more efficient a new interactive software was developed. It uses the contrast between the neuron under investigation and its surrounding for semi-automatic segmentation. For segmentation the user sets starting regions manually and the algorithm automatically selects a volume within the neuron until the edges corresponding to the neuronal outline are reached. Internally the algorithm optimizes a 3D active contour segmentation model formulated as a cost function taking the SEM image edges into account. This reduced the reconstruction time, while staying close to the manual reference segmentation result. Our algorithm is easy to use for a fast segmentation process, unlike previous methods it does not require image training nor an extended computing capacity. Our semi-automatic segmentation algorithm led to a dramatic reduction in processing time for the 3D-reconstruction of identified neurons. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. REVEALING THE SECRETS OF STONEHENGE THROUGH THE APPLICATION OF LASER SCANNING, PHOTOGRAMMETRY AND VISUALISATION TECHNIQUES

    Directory of Open Access Journals (Sweden)

    P. G. Bryan

    2013-07-01

    Full Text Available Stonehenge is perhaps the most famous prehistoric monument in the world. Begun as a simple earthwork enclosure, it was built in several stages with the unique lintelled stone circle being erected in the Neolithic period in around 2,500 BC. Today Stonehenge, together with Avebury and other associated sites, form the heart of a World Heritage Site (WHS with a unique and dense concentration of outstanding prehistoric monuments. In 2011 English Heritage (EH embarked on a new survey of the monument. Undertaken by the Greenhatch Group, a commercial survey company based near Derby, a combination of laser scanning and photogrammetric approaches were used to generate the required scale and detailed level of output required by English Heritage. This paper will describe the background to this project and its context within previous survey activities at this World Heritage Site. It will explain the data acquisition technology and processes undertaken on site, the datasets derived from post-processing and their filtering and analysis within both subsequent research projects. Alongside a description of how the data is currently being exploited and proposed future applications within the conservation and management of the site, it will finish by considering the impact of developing geospatial imaging technologies.

  17. Revealing the Secrets of Stonehenge Through the Application of Laser Scanning, Photogrammetry and Visualisation Techniques

    Science.gov (United States)

    Bryan, P. G.; Abbott, M.; Dodson, A. J.

    2013-07-01

    Stonehenge is perhaps the most famous prehistoric monument in the world. Begun as a simple earthwork enclosure, it was built in several stages with the unique lintelled stone circle being erected in the Neolithic period in around 2,500 BC. Today Stonehenge, together with Avebury and other associated sites, form the heart of a World Heritage Site (WHS) with a unique and dense concentration of outstanding prehistoric monuments. In 2011 English Heritage (EH) embarked on a new survey of the monument. Undertaken by the Greenhatch Group, a commercial survey company based near Derby, a combination of laser scanning and photogrammetric approaches were used to generate the required scale and detailed level of output required by English Heritage. This paper will describe the background to this project and its context within previous survey activities at this World Heritage Site. It will explain the data acquisition technology and processes undertaken on site, the datasets derived from post-processing and their filtering and analysis within both subsequent research projects. Alongside a description of how the data is currently being exploited and proposed future applications within the conservation and management of the site, it will finish by considering the impact of developing geospatial imaging technologies.

  18. Development of gamma probe technique for monitoring rooting pattern of pearl millet under field conditions

    International Nuclear Information System (INIS)

    Vittal, K.P.R.; Subbiah, B.V.

    1982-01-01

    For the root distribution studies, methods are not available to measure the growth in situ and in toto under field conditions without destroying the plants. A non-destructive method was developed for measuring the gamma activity in root using a probe that was administered through the stem. Five isotopes viz. 86 Rb, 134 Cs, 59 Fe, 65 Zn and 54 Mn tested, were found to represent almost similar rooting pattern for pearl millet from flowering to harvesting stages. Among these isotopes 59 Fe was found to be suitable for field use. This method also enabled to successfully monitor the root activity over time and avoided the sampling errors. Since laboratory processing of samples was eliminated, the process of measurement was hastened. (author)

  19. 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.

  20. Localized corrosion evaluation of the ASTM F139 stainless steel marked by laser using scanning vibrating electrode technique, X-ray photoelectron spectroscopy and Mott–Schottky techniques

    International Nuclear Information System (INIS)

    Pieretti, Eurico F.; Manhabosco, Sara M.; Dick, Luís F.P.; Hinder, Steve; Costa, Isolda

    2014-01-01

    Graphical abstract: SEM image of pits found at the centred marked area, where the laser beam focused twice. - Highlights: • The effect of laser engraving on the corrosion resistance of the ASTM F139 was studied. • Scanning vibrating electrode technique was used to identify the anodic zone. • Laser engraving of austenitic stainless steels produces highly defective surfaces. • Laser engraving causes large chemical modification of the surface. • Pitting nucleates at the interface between laser affected and unaffected areas. - Abstract: The effect of laser engraving on the corrosion resistance of ASTM F139 stainless steel (SS) has been investigated by electrochemical techniques. The nucleation of localized corrosion on this biomaterial was evaluated by scanning vibrating electrode technique (SVET) in a phosphate buffered saline solution (PBS) of pH 7.4. The Mott–Schottky approach was used to determine the electronic properties of the passive film, also chemically characterized by X-ray photoelectron spectroscopy (XPS). SVET allowed the identification of the anodic zones on the surface of the SS marked by laser technique that were associated with the heat-affected areas. Metallic drops solidified on the laser marked surface dissolved actively at OCP and favoured the nucleation of crevice corrosion, while at the pitting potential, pits nucleate preferentially on the laser marks. XPS results showed that laser engraving caused large chemical modification of the surface. Mott–Schottky results indicated a more defective oxide layer with a larger number of donors on the laser marked surface comparatively to that without marks