WorldWideScience

Sample records for force microscopic observation

  1. Direct observation of uncoated spectrin with atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    张平城; 白春礼; 成英俊; 方晔; 冯立明; 潘华珍

    1996-01-01

    Spectrin molecules extracted from human blood ceil membrane have been examined by atomic force microscopy (AFM) without using shadowing or staining procedures. A drop of the solution containing spectrin molecules was deposited on the freshly deaved mica substrate. After about 1 min, the residual solution was removed with a piece of filter paper. Afterwards the sample was imaged with a home-made atomic force microscope (AFM) in air in a constant force mode. The obtained AFM images revealed that the spectrin molecules prepared from the above procedures exhibit several kinds of structures as follows: (i) the compact rod-like spectrin heterodimers with a length of around 100 nm; (ii) bent or curved linear tetramers with a length of around 200 nm; (iii) somewhat curved spectrin hexamers, octomers or decamers with lengths of about 300, 400, or 500 nm; and (iv) high oligomers with a length above 1 000 nm.

  2. Atomic force microscopic observation of surface-supported human erythrocytes

    Science.gov (United States)

    Ho, Mon-Shu; Kuo, Feng-Jia; Lee, Yu-Siang; Cheng, Chao-Min

    2007-07-01

    The nanomechanical characteristics of the membrane cytoskeleton of human erythrocytes were studied using atomic force microscopy (AFM). The self-assembly, fine structure, cell diameter, thickness, and reticulate cytoskeleton of erythrocytes on the mica surface were investigated. The adhesive forces that correspond to the membrane elasticity of various parts of the erythrocyte membrane surface were measured directly by AFM to be 0.64±0.14nN for cell indentation, 4.2±0.7nN for cell hump, and 11.5nN for side waist, respectively. The deformation of erythrocytes was discussed. Standing waves on the membrane that were set up by increased AFM amplitude were observed. The propagating velocity on the erythrocyte membrane was estimated to be ˜2.02×10-2m/s. Liquid physiological conditions were considered throughout.

  3. Observation on Surface and Cross Section of Thin Film Solar Cells Using Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    FENG Liang-huan; WU Li-li; CAI Wei; CAI Ya-ping; ZHENG Jia-gui; ZHANG Jing-quan; LI Bing; LI Wei

    2005-01-01

    Atomic force microscope (AFM) is able to produce three-dimensional digital data in both forcemode and height-mode and its applications are not limited to map the surfaces of conducting materials. It can use the force-mode to image the repulsive and attractive force patterns. The cross sections of polycrystalline CdS/CdTe and amorphous silicon heterojunction solar cells are observed with AFM. In case of short circuit,the microstructures of different layers in the samples are clearly displayed. When the cells are open circuit, the topographical images are altered, the potential outline due to the space charge in junction region is observed.Obviously, AFM can be employed to investigate experimentally built-in potential in junction of semiconductor devices, such as solar cells.

  4. Atomic force microscope observation of branching in single transcript molecules derived from human cardiac muscle

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Jason; Hsueh, Carlin; Gimzewski, James K [Department of Chemistry and Biochemistry, UCLA, 607 Charles Young Drive East, Los Angeles, CA 90095 (United States); Mishra, Bud [Courant Institute of Mathematical Sciences, NYU, 251 Mercer Street, New York, NY 10012 (United States)], E-mail: jreed@chem.ucla.edu, E-mail: gim@chem.ucla.edu

    2008-09-24

    We have used an atomic force microscope to examine a clinically derived sample of single-molecule gene transcripts, in the form of double-stranded cDNA, (c: complementary) obtained from human cardiac muscle without the use of polymerase chain reaction (PCR) amplification. We observed a log-normal distribution of transcript sizes, with most molecules being in the range of 0.4-7.0 kilobase pairs (kb) or 130-2300 nm in contour length, in accordance with the expected distribution of mRNA (m: messenger) sizes in mammalian cells. We observed novel branching structures not previously known to exist in cDNA, and which could have profound negative effects on traditional analysis of cDNA samples through cloning, PCR and DNA sequencing.

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

    DEFF Research Database (Denmark)

    Jiang, Zaixing; Zhang, Shuai; Yang, Chuanxu;

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-01

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

  7. In situ observation of surface structures of cardiovascular endothelial cells with atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    Tong Yin; Jin Luo; YaMin Ma; Xiao-Long Ji; Yu-Sheng Zhao; Shi-Wen Wang

    2009-01-01

    Objective To observe the surface structures of cardiovascular endothelial cells in situ with atomic force microscope (AFM). Methods Fresh aorta and aortic valve were dissected from 10 healthy male New Zealand white rabbits. Before fixed in 1% formaldehyde, the fresh tissues were washed in the buffer phosphate solution. Under general microscope, the fixed aorta or valve was spread on the double side stick tape which had already been stuck on the glass slide. The intima of aorta or the aorta side of valve was towards upside. Then the specimen was dried under 37 degrees centigrade in an attemperator and was washed with pure water. After dried again, the specimen was loaded on the platform ofNanoScope llla AFM and was scanned in tapping mode with the scanning speed of 0.5 HZ. Results The surface structures of endothelial cell on the fixed and dried tissue could be obsserved clearly in situ with AFM. Aortic endothclial cells were large, branched and arranged sparsely and parallel to the direction of blood flow, whereas endothelial cells on aorta valve surface were small, less branched and arranged intensively and vertical to the direction of blood flow. When the scanning range was dwindled, granular ultra-structures could be observed on the surface of endothelial cells, and, as the scanning range was dwindled further, fissure and convolution could be seen on the surface of granules from aortic endothelial cells. Centre cavity and surrounding swelling volcano-like structure could be seen on the surface of granules from endothelial cells of aortic valve. Conclusions It's feasible to observe the surface ultra-structures of cardiovascular endothelial cells in situ with AFM and morphological information provided by A FM might be of clinical value in future histopathological diagnosis.

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

    Science.gov (United States)

    Yang, Fei; Xu, Ling; Zhang, Rui; Geng, Lei; Tong, Liang; Xu, Jun; Su, Weining; Yu, Yao; Ma, Zhongyuan; Chen, Kunji

    2012-10-01

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

  9. Atomic force microscopic observation on substructure of pollen exine in Cedrus deodara and Metasequoia glyptostroboides

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The substructure of pollen exine in Cedrus deodara (Roxb.) Loud. and Metasequoia glyptostroboides Hu et Cheng has been examined with an atomic force microscope (AFM). The results indicate that the exine substructure units containing sporopollenin in two species are similar in shape, which are granular, but slightly different in size. In Cedrus the substructure unit of pollen exine appears to be 56-99 nm long and 42-74 nm wide, while in Metasequoia it appears to be 81-118 nm long and 43-98 nm wide. It has been observed that the subunits of pollen exine in Cedrus arranged tightly to form short-rod-like or spheroidal pollen exine units, several or more than ten of which formed an island-like structure. There are various spaces among these island-like structures which are interconnected to occupy the entire pollen exine. In Metasequoia, the subunits of pollen exine also arranged tightly with a distribution tendency of cluster of 3-10, however, no obvious boundary exists among these clusters. From our results, it is concluded that there is no tendency of helical arrangement for the subunits of pollen exine in Cedrus and Metasequoia, and the results support Southworth' view that subunits of pollen exine are granular shape in lattice structure.

  10. Atomic Force Microscope

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-12-01

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

  11. Atomic Force Microscope Operation

    Science.gov (United States)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation (large file) This animation is a scientific illustration of the operation of NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA. The AFM is used to image the smallest Martian particles using a very sharp tip at the end of one of eight beams. The beam of the AFM is set into vibration and brought up to the surface of a micromachined silicon substrate. The substrate has etched in it a series of pits, 5 micrometers deep, designed to hold the Martian dust particles. The microscope then maps the shape of particles in three dimensions by scanning them with the tip. At the end of the animation is a 3D representation of the AFM image of a particle that was part of a sample informally called 'Sorceress.' The sample was delivered to the AFM on the 38th Martian day, or sol, of the mission (July 2, 2008). The image shows four round pits, only 5 microns in depth, that were micromachined into the silicon substrate. A Martian particle only one micrometer, or one millionth of a meter, across is held in the upper left pit. The rounded particle shown at the highest magnification ever seen from another world is a particle of the dust that cloaks Mars. Such dust particles color the Martian sky pink, feed storms that regularly envelop the planet and produce Mars' distinctive red soil. The AFM was developed by a Swiss-led consortium, with Imperial College London producing the silicon substrate that holds sampled particles. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  12. Atomic force microscope tracking observation of Chinese hamster ovary cell mitosis.

    Science.gov (United States)

    Wu, Yangzhe; Cai, Jiye; Cheng, Longqiu; Xu, Yanfang; Lin, Zhiyan; Wang, Chenxi; Chen, Yong

    2006-01-01

    CHO cells possess easily identifiable karyotypes, and CHO cell chromosomes are large and few in number, making these cells ideal for mutational and drug toxicity studies and suitable for investigations of animal chromosome structure. Here, we used atomic force microscopy (AFM) in the tapping mode for detailed visualizations of Chinese hamster ovary (CHO) cell chromosomes during various mitotic phases, including typical prophase, prometaphase, metaphase, anaphase and telophase. Based on our detailed observations, we were able to divide metaphase and anaphase into sub-phases: metaphase I, II and III, and anaphase I and II. Furthermore, we used the AFM error-signal mode to visualize chromosomal ultrastructures and cytokinesis. While these visualizations were all successful, we found that the image quality was affected by cellular debris, contamination. Collectively, our results show that the AFM technique has great potential for the detailed study of chromosomes and chromosomal ultrastructures during all phases of the cell cycle, but that careful standards of sample preparation must be maintained.

  13. Competitive Adsorption between Bovine Serum Albumin and Collagen Observed by Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    Yong YU; Pei Qing YING; Gang JIN

    2004-01-01

    Atomic force microscopy (AFM) was used to study the competitive adsorption between bovine serum albumin (BSA) and type Ⅰ collagen on hydrophilic and hydrophobic silicon wafers.BSA showed a grain shape and the type I collagen displayed fibril-like molecules with relatively homogeneous height and width, characterized with clear twisting (helical formation). These AFM images illustrated that quite a lot of type I collagen appeared in the adsorption layer on hydrophilic surface in a competitive adsorption state, but the adsorption of BSA was more preponderant than that of type I collagen on hydrophobic silicon wafer surface. The experiments showed that the influence of BSA on type I collagen adsorption on hydrophilic surface was less than that on hydrophobic surface.

  14. Coaxial Atomic Force Microscope Tweezers

    CERN Document Server

    Brown, K A; Westervelt, R M

    2010-01-01

    We demonstrate coaxial atomic force microscope (AFM) tweezers that can trap and place small objects using dielectrophoresis (DEP). An attractive force is generated at the tip of a coaxial AFM probe by applying a radio frequency voltage between the center conductor and a grounded shield; the origin of the force is found to be DEP by measuring the pull-off force vs. applied voltage. We show that the coaxial AFM tweezers (CAT) can perform three dimensional assembly by picking up a specified silica microsphere, imaging with the microsphere at the end of the tip, and placing it at a target destination.

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

    NARCIS (Netherlands)

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

    1994-01-01

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

  16. The Development of the High-Resolution Transmission Electron Microscope (HRTEM) Combined with AFM for Simultaneous Observation of Structure and Force of the Nanocontact

    Science.gov (United States)

    Shibata, Sakiko; Tanishiro, Yasumasa; Kondo, Yukihito; Minoda, Hiroki; Takayanagi, Kunio

    2004-03-01

    A high-resolution transmission electron microscope combined with an atomic force microscope (HRTEM-AFM) has been developed. It enables us to observe mechanical force and atomic structure of nanowires formed at the nanocontact simultaneously. And the self-sensing piezoresistive cantilever is used as an AFM probe in the HRTEM-AFM. It has high spatial resolution of 0.2nm and high force sensitivity of sub-nN. The HRTEM has also ability to work on ultra high vacuum(UHV) which is necessary to keep the nanocontact clean. The present system could never be developed without total redesigning of the goniometer stage of UHV-TEM which operates at 10-8 Pa.

  17. Atomic Force Microscope Mediated Chromatography

    Science.gov (United States)

    Anderson, Mark S.

    2013-01-01

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

  18. Variable - temperature scanning optical and force microscope

    OpenAIRE

    2004-01-01

    The implementation of a scanning microscope capable of working in confocal, atomic force and apertureless near field configurations is presented. The microscope is designed to operate in the temperature range 4 - 300 K, using conventional helium flow cryostats. In AFM mode, the distance between the sample and an etched tungsten tip is controlled by a self - sensing piezoelectric tuning fork. The vertical position of both the AFM head and microscope objective can be accurately controlled using...

  19. Atomic force microscope featuring an integrated optical microscope

    NARCIS (Netherlands)

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

    1992-01-01

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

  20. First Atomic Force Microscope Image from Mars

    Science.gov (United States)

    2008-01-01

    This calibration image presents three-dimensional data from the atomic force microscope on NASA's Phoenix Mars Lander, showing surface details of a substrate on the microscope station's sample wheel. It will be used as an aid for interpreting later images that will show shapes of minuscule Martian soil particles. The area imaged by the microscope is 40 microns by 40 microns, small enough to fit on an eyelash. The grooves in this substrate are 14 microns (0.00055 inch) apart, from center to center. The vertical dimension is exaggerated in the image to make surface details more visible. The grooves are 300 nanometers (0.00001 inch) deep. This is the first atomic force microscope image recorded on another planet. It was taken on July 9, 2008, during the 44th Martian day, or sol, of the Phoenix mission since landing. Phoenix's Swiss-made atomic force microscope builds an image of the surface shape of a particle by sensing it with a sharp tip at the end of a spring, all microfabricated out of a silicon wafer. A strain gauge records how far the spring flexes to follow the contour of the surface. It can provide details of soil-particle shapes smaller than one-hundredth the width of a human hair. This is about 20 times smaller than what can be resolved with Phoenix's optical microscope, which has provided much higher-magnification imaging than anything seen on Mars previously. Both microscopes are part of Phoenix's Microscopy, Electrochemistry and Conductivity Analyzer.

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

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

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

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

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

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

  3. Sharp Tips on the Atomic Force Microscope

    Science.gov (United States)

    2008-01-01

    This image shows the eight sharp tips of the NASA's Phoenix Mars Lander's Atomic Force Microscope, or AFM. The AFM is part of Phoenix's Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA. The microscope maps the shape of particles in three dimensions by scanning them with one of the tips at the end of a beam. For the AFM image taken, the tip at the end of the upper right beam was used. The tip pointing up in the enlarged image is the size of a smoke particle at its base, or 2 microns. This image was taken with a scanning electron microscope before Phoenix launched on August 4, 2007. The AFM was developed by a Swiss-led consortium in collaboration with Imperial College London. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  4. Atomic Force Microscope for Imaging and Spectroscopy

    Science.gov (United States)

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

    2000-01-01

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

  5. Adaptive control of force microscope cantilever dynamics

    Science.gov (United States)

    Jensen, S. E.; Dougherty, W. M.; Garbini, J. L.; Sidles, J. A.

    2007-09-01

    Magnetic resonance force microscopy (MRFM) and other emerging scanning probe microscopies entail the detection of attonewton-scale forces. Requisite force sensitivities are achieved through the use of soft force microscope cantilevers as high resonant-Q micromechanical oscillators. In practice, the dynamics of these oscillators are greatly improved by the application of force feedback control computed in real time by a digital signal processor (DSP). Improvements include increased sensitive bandwidth, reduced oscillator ring up/down time, and reduced cantilever thermal vibration amplitude. However, when the cantilever tip and the sample are in close proximity, electrostatic and Casimir tip-sample force gradients can significantly alter the cantilever resonance frequency, foiling fixed-gain narrow-band control schemes. We report an improved, adaptive control algorithm that uses a Hilbert transform technique to continuously measure the vibration frequency of the thermally-excited cantilever and seamlessly adjust the DSP program coefficients. The closed-loop vibration amplitude is typically 0.05 nm. This adaptive algorithm enables narrow-band formally-optimal control over a wide range of resonance frequencies, and preserves the thermally-limited signal to noise ratio (SNR).

  6. Digital atomic force microscope Moire method

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.-M. [Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China); Chen, L.-W. [Department of Mechanical Engineering, National Cheng Kung University, Tainan 70101, Taiwan (China)]. E-mail: chenlw@mail.ncku.edu.tw

    2004-11-15

    In this study, a novel digital atomic force microscope (AFM) moire method is established to measure the displacement and strain fields. The moire pattern is generated by the interference between the specimen grating and the virtual reference grating formed by digital image processes. The overlapped image is filtered by the 2-D wavelet transformation to obtain clear interference moire patterns. From moire patterns, the displacement and strain fields can be analyzed. The experimental results show that the digital AFM moire method is very sensitive and easy to realize in nanoscale measurements.

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

    DEFF Research Database (Denmark)

    Jensen, Carsten P.

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

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

    DEFF Research Database (Denmark)

    Jensen, Carsten P.

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

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

    NARCIS (Netherlands)

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

    1992-01-01

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

  10. Polymerized LB films imaged with a combined atomic force microscope-fluorescence microscope

    NARCIS (Netherlands)

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

    1992-01-01

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

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

    NARCIS (Netherlands)

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

    1992-01-01

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

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

    NARCIS (Netherlands)

    Shevchenko, A.; Hoenders, B. J.

    2010-01-01

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

  13. Observation of Switchable Photoresponse of a Monolayer WSe 2 –MoS 2 Lateral Heterostructure via Photocurrent Spectral Atomic Force Microscopic Imaging

    KAUST Repository

    Son, Youngwoo

    2016-04-27

    In the pursuit of two-dimensional (2D) materials beyond graphene, enormous advances have been made in exploring the exciting and useful properties of transition metal dichalcogenides (TMDCs), such as a permanent band gap in the visible range and the transition from indirect to direct band gap due to 2D quantum confinement, and their potential for a wide range of device applications. In particular, recent success in the synthesis of seamless monolayer lateral heterostructures of different TMDCs via chemical vapor deposition methods has provided an effective solution to producing an in-plane p-n junction, which is a critical component in electronic and optoelectronic device applications. However, spatial variation of the electronic and optoelectonic properties of the synthesized heterojunction crystals throughout the homogeneous as well as the lateral junction region and the charge carrier transport behavior at their nanoscale junctions with metals remain unaddressed. In this work, we use photocurrent spectral atomic force microscopy to image the current and photocurrent generated between a biased PtIr tip and a monolayer WSe2-MoS2 lateral heterostructure. Current measurements in the dark in both forward and reverse bias reveal an opposite characteristic diode behavior for WSe2 and MoS2, owing to the formation of a Schottky barrier of dissimilar properties. Notably, by changing the polarity and magnitude of the tip voltage applied, pixels that show the photoresponse of the heterostructure are observed to be selectively switched on and off, allowing for the realization of a hyper-resolution array of the switchable photodiode pixels. This experimental approach has significant implications toward the development of novel optoelectronic technologies for regioselective photodetection and imaging at nanoscale resolutions. Comparative 2D Fourier analysis of physical height and current images shows high spatial frequency variations in substrate/MoS2 (or WSe2) contact that

  14. Reconstructing the distributed force on an atomic force microscope cantilever

    Science.gov (United States)

    Wagner, Ryan; Killgore, Jason

    2017-03-01

    A methodology is developed to reconstruct the force applied to an atomic force microscopy (AFM) cantilever given the shape in which it vibrates. This is accomplished by rewriting Bernoulli–Euler beam theory such that the force on the cantilever is approximated as a linear superposition of the theoretical cantilever eigenmodes. The weighting factors in this summation are calculated from the amplitude and phase measured along the length of the cantilever. The accuracy of the force reconstruction is shown to depend on the frequency at which the measurement is performed, the number of discrete points measured along the length of the cantilever, and the signal-to-noise ratio of the measured signal. In contrast to other AFM force reconstruction techniques, this method can reconstruct the distribution of force applied over the length of the AFM cantilever. However, this method performs poorly for localized forces applied to the cantilever, such as is typical of most tip–sample interaction forces. Proof of concept experiments are performed on an electrostatically excited cantilever and the expected force distribution is recovered. This force reconstruction technique offers previously unavailable insight into the distributed forces experienced by an AFM cantilever.

  15. Microscopic origin of Casimir-Polder forces

    OpenAIRE

    2006-01-01

    We establish a general relation between dispersion forces. First, based on QED in causal media, leading-order perturbation theory is used to express both the single-atom Casimir-Polder and the two-atom van der Waals potentials in terms of the atomic polarizabilities and the Green tensor for the body-assisted electromagnetic field. Endowed with this geometry-independent framework, we then employ the Born expansion of the Green tensor together with the Clausius-Mosotti relation to prove that th...

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  17. Edge Effects and Coupling Effects in Atomic Force Microscope Images

    Institute of Scientific and Technical Information of China (English)

    ZHANGXiang-jun; MENGYong-gang; WENShi-zhu

    2004-01-01

    The AFM images were obtained by an atomic force microscope (AFM) and transformed from the deformation of AFM micro cantilever probe. However, due to the surface topography and surface forces applied on the AFM tip of sample, the deformation of AFM probe results in obvious edge effects and coupling effects in the AFM images. The deformation of AFM probe was analyzed,the mechanism of the edge effects and the coupling effects was investigated, and their results in the AFM images were studied. It is demanstrated by the theoretical analysis and AFM experiments that the edge effects make lateral force images more clear than the topography images, also make extraction of frictional force force from lateral force images mare complex and difficult. While the coupling effects make the comparison between topography images and lateral force images mare advantage to acquire precise topography information by AFM.

  18. New approaches to atomic force microscope lithography on silicon

    DEFF Research Database (Denmark)

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

    1997-01-01

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

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

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  20. Atomic force microscope characterization of a resonating nanocantilever

    DEFF Research Database (Denmark)

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

    2003-01-01

    An atomic force microscope (AFM) is used as a nanometer-scale resolution tool for the characterization of the electromechanical behaviour of a resonant cantilever-based mass sensor. The cantilever is actuated electrostatically by applying DC and AC voltages from a driver electrode placed closely...

  1. Stitching Grid-wise Atomic Force Microscope Images

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  2. Stitching Grid-wise Atomic Force Microscope Images

    DEFF Research Database (Denmark)

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

    2016-01-01

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

  3. Resonant difference-frequency atomic force ultrasonic microscope

    Science.gov (United States)

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

    2010-01-01

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

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

    Science.gov (United States)

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

    2011-07-15

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, Seiji; Kubo, Osamu; Kuramochi, Hiromi; Aono, Masakazu; Nakayama, Tomonobu, E-mail: higuchi.seiji@nims.go.jp, E-mail: nakayama.tomonobu@nims.go.jp [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0044 (Japan)

    2011-07-15

    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.

  6. Controlled manipulation of nanoparticles with an atomic force microscope

    Science.gov (United States)

    Junno, T.; Deppert, K.; Montelius, L.; Samuelson, L.

    1995-06-01

    We report on the application of the atomic force microscope (AFM) to manipulate and position nanometer-sized particles with nanometer precision. The technique, which can be regarded as a nanometer-scale analogy to atomic level manipulation with the scanning tunneling microscope, allowed us to form arbitrary nanostructures, under ambient conditions, by controlled manipulation of individual 30 nm GaAs particles. A whole new set of nanodevices can be fabricated particle-by-particle for studies of quantum effects and single electron tunneling. We also demonstrate a method, based on the AFM manipulation, to determine the true lateral dimensions of nano-objects, in spite of the tip-sample convolution.

  7. Imaging using lateral bending modes of atomic force microscope cantilevers

    Science.gov (United States)

    Caron, A.; Rabe, U.; Reinstädtler, M.; Turner, J. A.; Arnold, W.

    2004-12-01

    Using scanning probe techniques, surface properties such as shear stiffness and friction can be measured with a resolution in the nanometer range. The torsional deflection or buckling of atomic force microscope cantilevers has previously been used in order to measure the lateral forces acting on the tip. This letter shows that the flexural vibration modes of cantilevers oscillating in their width direction parallel to the sample surface can also be used for imaging. These lateral cantilever modes exhibit vertical deflection amplitudes if the cantilever is asymmetric in thickness direction, e.g., by a trapezoidal cross section.

  8. US Air Force Base Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hourly observations taken by U.S. Air Force personnel at bases in the United States and around the world. Foreign observations concentrated in the Middle East and...

  9. MIDAS: Lessons learned from the first spaceborne atomic force microscope

    CERN Document Server

    Bentley, Mark S; Butler, Bart; Gavira, Jose; Jeszenszky, Harald; Mannel, Thurid; Romstedt, Jens; Schmied, Roland; Torkar, Klaus

    2016-01-01

    The Micro-Imaging Dust Analysis System (MIDAS) atomic force microscope (AFM) onboard the Rosetta orbiter was the first such instrument launched into space in 2004. Designed only a few years after the technique was invented, MIDAS is currently orbiting comet 67P Churyumov-Gerasimenko and producing the highest resolution 3D images of cometary dust ever made in situ. After more than a year of continuous operation much experience has been gained with this novel instrument. Coupled with operations of the Flight Spare and advances in terrestrial AFM a set of "lessons learned" has been produced, cumulating in recommendations for future spaceborne atomic force microscopes. The majority of the design could be reused as-is, or with incremental upgrades to include more modern components (e.g. the processor). Key additional recommendations are to incorporate an optical microscope to aid the search for particles and image registration, to include a variety of cantilevers (with different spring constants) and a variety of ...

  10. Microstructural Observation of Leucaena glaucal Seed Polysaccharides under Atomic Force Microscope%银合欢种子多糖微结构的原子力显微镜观察

    Institute of Scientific and Technical Information of China (English)

    杨永利; 郭守军; 叶文斌; 潘显辉; 林月娟; 林海雄

    2012-01-01

    Objective: The microstructure of Leucaena glaucal seed polysaccharides was studied based on morphological observation under atomic force microscope(AFM).Methods: Polysaccharides from were extracted by hot water extraction.The structure and morphology of aggregates and non-aggregates from Leucaena glaucal seed polysaccharides formed through varying polysaccharide concentration or chemically modifying the surface of mica substrates were visualized under AFM.Results: Membranous,granular aggregates structure and non-aggregate structure of a single polysaccharide molecule could be observed in the samples prepared at various conditions.Conclusion: A single Leucaena glaucal seeds polysaccharide molecule was linear spiral,and had short branch structure and entangled molecular chains to form a reticulation structure.%目的:通过对银合欢种子多糖的形貌观察,研究其微结构。方法:采用热水浸提法提取银合欢种子多糖,通过改变溶液的质量浓度、云母基底表面的化学修饰等不同制样方式,用原子力显微镜(AFM)可视化不同样品制备条件形成的聚集体和非聚集体银合欢半乳甘露聚糖结构形貌。结果:样品在不同制备条件下得到膜状、颗粒状的聚集体结构和非聚集体单糖分子结构。结论:银合欢种子多糖的单个糖分子呈线形螺旋状,并具有短的分枝结构,分子链间互相缠绕,而形成网格状。

  11. Experimental Investigation of the Velocity Effect on Adhesion Forces with an Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    魏征; 赵亚溥

    2004-01-01

    Capillary forces are significantly dominant in adhesive forces measured with an atomic force microscope (AFM)in ambient air, which are always thought to be dependent on water film thickness, relative humidity, and the free energy of water film. We study the nature of the pull-off force on a variety of surfaces as a function of tip velocity.It is found that the capillary forces are of relatively strong dependence on tip velocity. The present experiment is expected to provide a better understanding of the work mechanism of AFM in ambient air.

  12. Influence of scanning force microscope loading force on measurement of ion—track diameter

    Institute of Scientific and Technical Information of China (English)

    WangYu-Gang; AckermannJ; 等

    1997-01-01

    Scanning force microscope(SFM) was operated in the lateral-force mode with different loading forces.The mica samples were irradiated by Se ions with a kinetic energy of 11.4MeV/u.The"full-height width" and the "half-height width" of track profiles were used to evaluate the ion-track diameter,For the former method,the average track diameter increases slowly with increasing loading force between SFM tip and sample.For the later method,the average diameters of ion track nearly keep a common value as the SFM loading force increases.

  13. Adhesion Force Measurements Using an Atomic Force Microscope Upgraded with a Linear Position Sensitive Detector

    Science.gov (United States)

    Pierce, M.; Stuart, J.; Pungor, A.; Dryden, P.

    2012-01-01

    The atomic force microscope (AFM), in addition to providing images on an atomic scale, can be used to measure the forces between surfaces and the AFM probe. The potential uses of mapping the adhesive forces on the surface include a spatial determination of surface energy and a direct identification of surface proteins through specific protein–ligand binding interactions. The capabilities of the AFM to measure adhesive forces can be extended by replacing the four-quadrant photodiode detection sensor with an external linear position sensitive detector and by utilizing a dedicated user-programmable signal generator and acquisiton system. Such an upgrade enables the microscope to measure in the larger dynamic range of adhesion forces, improves the sensitivity and linearity of the measurement, and eliminates the problems inherent to the multiple repetitious contacts between the AFM probe and the specimen surface. PMID:25125792

  14. DURIP: Piezoresponse Force Microscope (PFM) with Controlled Environment for Characterization of Flexoelectric Nanostructures

    Science.gov (United States)

    2015-04-21

    DURIP: Piezoresponse Force Microscope (PFM) with Controlled Environment for Characterization of Flexoelectric Nanostructures A piezo-force... microscope (PFM) system was acquired under this support for characterization of flexoelectric micro/nanostructures in a controlled environment. The system...published in non peer-reviewed journals: Final Report: DURIP: Piezoresponse Force Microscope (PFM) with Controlled Environment for Characterization of

  15. Nonlinear control techniques for an atomic force microscope system

    Institute of Scientific and Technical Information of China (English)

    Yongchun FANG; Matthew FEEMSTER; Darren DAWSON; Nader M.JALILI

    2005-01-01

    Two nonlinear control techniques are proposed for an atomic force microscope system.Initially,a learning-based control algorithm is developed for the microcantilever-sample system that achieves asymptotic cantilever tip tracking for periodic trajectories.Specifically,the control approach utilizes a learning-based feedforward term to compensate for periodic dynamics and high-gain terms to account for non-periodic dynamics.An adaptive control algorithm is then developed to achieve asymptotic cantilever tip tracking for bounded tip trajectories despite uncertainty throughout the system parameters.Simulation results are provided to illustrate the efficacy and performance of the control strategies.

  16. Scanned-cantilever atomic force microscope with large scanning range

    Institute of Scientific and Technical Information of China (English)

    Jintao Yang; Wendong Xu

    2006-01-01

    A scanned-cantilever atomic force microscope (AFM) with large scanning range is proposed, which adopts a new design named laser spot tracking. The scanned-cantilever AFM uses the separate flexure x-y scanner and z scanner instead of the conventional piezoelectric tube scanner. The closed-loop control and integrated capacitive sensors of these scanners can insure that the images of samples have excellent linearity and stability. According to the experimental results, the scanned-cantilever AFM can realize maximal 100 × 100 (μm) scanning range, and 1-nm resolution in z direction, which can meet the requirements of large scale sample testing.

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

    Science.gov (United States)

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

    2015-01-01

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

  18. Measuring microscopic forces and torques using optical tweezers

    CSIR Research Space (South Africa)

    McLaren, MG

    2009-07-01

    Full Text Available f1 f2 f 3 Objective lens Illumination source M1 M2 Dichroic mirror Sample stage Our home-built optical trapping and tweezing setup, complete with in-house microscope objective Optical tweezing and micromanipulation, MSc (Wits), 2009 60.5 µm... v v α−= Velocity of fluid as bead escapes trap Trap stiffnessViscosity of fluid Drag force method Drag force method mW 100at pN 26.024.5 =±= PFtrap Equipartition Method Tkx B2 1 2 1 2 =α N/m 105109.9 -65 ×±×= −α xF v v α...

  19. Accurate measurement of microscopic forces and torques using optical tweezers

    Directory of Open Access Journals (Sweden)

    Andrew Forbes

    2011-09-01

    Full Text Available It is now well known that matter may be trapped by optical fields with high intensity gradients. Once trapped, it is then possible to manipulate microscopic particles using such optical fields, in so-called optical tweezers. Such optical trapping and tweezing systems have found widespread application across diverse fields in science, from applied biology to fundamental physics. In this article we outline the design and construction of an optical trapping and tweezing system, and show how the resulting interaction of the laser light with microscopic particles may be understood in terms of the transfer of linear and angular momentum of light. We demonstrate experimentally the use of our optical tweezing configuration for the measurement of microscopic forces and torques. In particular, we make use of digital holography to create so-called vortex laser beams, capable of transferring orbital angular momentum to particles. The use of such novel laser beams in an optical trapping and tweezing set-up allows for the control of biological species at the single-cell level.

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

    Science.gov (United States)

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

    2009-07-01

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

  1. Atomic force microscope chamber for in situ studies of ice

    Science.gov (United States)

    Zepeda, Salvador; Yeh, Yin; Orme, Christine A.

    2001-11-01

    To investigate the surface morphologies of biological systems in a controlled gaseous environment (e.g., the temperature, humidity and composition), most commercial atomic force microscopes require modification. We have designed a double-jacketed environmental chamber specifically for a Nanoscope IIIa (Digital Instruments, Santa Barbara, CA) force microscope. We use cold nitrogen and thermoelectric devices to control the temperature in the chamber; the nitrogen simultaneously serves to create an inert environment. We have also designed a temperature controlled sample stage utilizing thermoelectric devices for fine temperature regulation. A variation of this sample stage allows us to image samples in fluids at cold temperatures with an O-ringless configuration. The relative humidity within the chamber is also measured with commercially available relative humidity sensors. We investigate the surface morphology of ice Ih in its pure phase and shall extend the study to ice in the presence of biological molecules, such as antifreeze proteins. We present a detailed description of our design and our first images of polycrystalline ice and single crystals of ice grown in situ from the vapor.

  2. Influence of atomic force microscope (AFM) probe shape on adhesion force measured in humidity environment

    Institute of Scientific and Technical Information of China (English)

    阳丽; 涂育松; 谭惠丽

    2014-01-01

    In micro-manipulation, the adhesion force has very important influence on behaviors of micro-objects. Here, a theoretical study on the effects of humidity on the adhesion force is presented between atomic force microscope (AFM) tips and substrate. The analysis shows that the precise tip geometry plays a critical role on humidity depen-dence of the adhesion force, which is the dominant factor in manipulating micro-objects in AFM experiments. For a blunt (paraboloid) tip, the adhesion force versus humidity curves tends to the apparent contrast (peak-to-valley corrugation) with a broad range. This paper demonstrates that the abrupt change of the adhesion force has high correla-tion with probe curvatures, which is mediated by coordinates of solid-liquid-vapor contact lines (triple point) on the probe profiles. The study provides insights for further under-standing nanoscale adhesion forces and the way to choose probe shapes in manipulating micro-objects in AFM experiments.

  3. Measurement of inter-particle forces by an interfacial force microscope

    Institute of Scientific and Technical Information of China (English)

    Qing Huang; Asghar Mesbah-Nejad; Seyed M. Tadayyon; Peter Norton; Hui Zhang; Jesse Zhu

    2010-01-01

    An inteffacial force microscope (IFM) was employed to measure the inter-particle forces between two individual glass beads with diameters varying from 8 to 20 μm. With the feedback function of IFM turned off, attractive forces were obtained. The forces varied in the range of 0.1-0.34 μN, and their validity was confirmed by a theoretical analysis of the van der Waals force between the same glass beads. With the feedback function switched on, no attractive forces between particles were detected by the IFM when the probe approached the sample substrate. This may be attributed to the dramatic change of the attractive forces within a very short separation distance and/or the relatively poor signal-to-noise ratio of the IFM.

  4. Surface Electromechanical Coupling on DLC Film with Conductive Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    朱守星; 丁建宁; 范真; 李长生; 蔡兰; 杨继昌

    2004-01-01

    Diamond-like carbon (DLC) film composed of microscopically insulation but microscopically a mixture of conducting (sp2) and insulating (spa) phases was discussed on the local modification with a conductive atomic force microscope (C-AFM). Especially, a topographic change was observed when a direct current (DC) bias-voltage was applied to the DLC film. Experimental results show that a nanoscale pit on DLC surface was formed when applying a positive 25 V on DLC film. According to the interacting force between CoCr-coated microelectronic scanning probe (MESP) tip and DLC surface, as well as the Sondheimer oscillation theory, the "scalewing effect" of the pit was explained. Electromechanical coupling on DLC film suggested that the depth of pits increased with an increase of load applied to surface when the cantilever-deflected signal was less than a certain threshold voltage.

  5. Interlaboratory comparison of traceable atomic force microscope pitch measurements

    Science.gov (United States)

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

    2010-06-01

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

  6. 白术多糖WAM-1结构的色谱分析和原子力显微镜观察%Chromatographic Analysis and Atomic Force Microscope Observation of Polysaccharide Extracted from Atractylodes macrocephala Koidz.

    Institute of Scientific and Technical Information of China (English)

    伍乐芹; 姜绍芬; 张静

    2012-01-01

    Polysaccharides extracted from the stem of Atractylodes macrocephala Koidz by hot water,were fractionated by DEAE-52 cellulose chromatography,and purified by Sephadex G-200 gel filtration chromatography to obtain a fraction, named WAM-1. HPLC and GC analysis showed that WAM-1 was a homogeneous and consisted of glucose and galactose in the molar ratio of 3. 01: 1. The molecular morphology of WAM-1 was observed under an atomic force microscope (AFM).The results showed that WAM-1 existed in different forms with different concentrations. The concentration of polysaccharide had effects on the conformation and form of chain interactions, which might be related to the interaction of intramolecular and intermolecular hydrogen bonds. At 10 μg/mL,the morphology of WAM-1 was observed clearly in rigid chains with many branches.%通过热水浸提法从草本植物白术根茎提取的水溶性粗多糖,经DEAE-52纤维素柱层析分离和Sephadex G-200凝胶过滤柱层析纯化,得到组分WAM-1.采用高效液相色谱(HPLC)检测WAM-1的纯度,气相色谱(GC)对其单糖组分进行分析,原子力显微镜(AFM)对其分子外貌进行观测.结果显示:WAM-1为均一多糖,由葡萄糖和半乳糖以3.01:1摩尔比构成;在不同浓度溶液条件下,WAM-1分子以不同形态存在,多糖溶液的浓度对WAM-1的分子链构象及链间相互作用形式产生影响,推测可能与WAM-1分子内、分子间的氢键缔合作用有关.多糖浓度为10μg/mL时,可清晰的观察到WAM-1是以刚性链状形态存在,且具有多分支结构.

  7. Theoretical Study on the Capillary Force between an Atomic Force Microscope Tip and a Nanoparticle

    Institute of Scientific and Technical Information of China (English)

    LI Zhao-Xia; ZHANG Li-Juan; YI Hou-Hui; FANG Hai-Ping

    2007-01-01

    @@ Considering that capillary force is one of the most important forces between nanoparticles and atomic force microscope (AFM) tips in ambient atmosphere, we develop an analytic approach on the capillary force between an AFM tip and a nanoparticle. The results show that the capillary forces are considerably affected by the geometry of the AFM tip, the humidity of the environment, the vertical distance between the AFM tip and the nanoparticle, as well as the contact angles of the meniscus with an AFM tip and a nanoparticle. It is found that the sharper the AFM tip, the smaller the capillary force. The analyses and results are expected to be helpful for the quantitative imaging and manipulating of nanoparticles by AFMs.

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

    NARCIS (Netherlands)

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

    1992-01-01

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

  9. A Study on HA Titanium Surface with Atomic Force Microscope (AFM)

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Three kinds of titanium surface especially the HA surface are analyzed. Titanium was treated by 3 kinds of methods that were acid & alkali, calcic solution and apatite solution. Samples were observed by optic microscope and atomic force microscope ( AFM). The typical surface morphology of the acid and alkali group is little holes, and on the two HA surface the tiny protuberances is typical. The surface treated by apatite solution was smoother than the two formers. The rough surface treated with acid and alkali was propitious to Ca + , Pand proteins' adhesion, and the relatively smooth HA surface was of benefit to the cell adhesion.

  10. The development of a novel electromagnetic force microscope

    CERN Document Server

    Windmill, J F C

    2002-01-01

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

  11. Digital phase-shifting atomic force microscope Moire method

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chiaming; Chen Lienwen [Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan, 70101 (China)

    2005-04-21

    In this study, the digital atomic force microscope (AFM) Moire method with phase-shifting technology is established to measure the in-plane displacement and strain fields. The Moire pattern is generated by the interference between the specimen grating and the virtual reference grating formed by digital image processes. The overlapped image is filtered by two-dimensional wavelet transformation to obtain the clear interference Moire patterns. The four-step phase-shifting method is realized by translating the phase of the virtual reference grating from 0 to 2{pi}. The principle of the digital AFM Moire method and the phase-shifting technology are described in detail. Experimental results show that this method is convenient to use and efficient in realizing the microscale measurement.

  12. Atomic force microscope based on vertical silicon probes

    Science.gov (United States)

    Walter, Benjamin; Mairiaux, Estelle; Faucher, Marc

    2017-06-01

    A family of silicon micro-sensors for Atomic Force Microscope (AFM) is presented that allows to operate with integrated transducers from medium to high frequencies together with moderate stiffness constants. The sensors are based on Micro-Electro-Mechanical-Systems technology. The vertical design specifically enables a long tip to oscillate perpendicularly to the surface to be imaged. The tip is part of a resonator including quasi-flexural composite beams, and symmetrical transducers that can be used as piezoresistive detector and/or electro-thermal actuator. Two vertical probes (Vprobes) were operated up to 4.3 MHz with stiffness constants 150 N/m to 500 N/m and the capability to oscillate from 10 pm to 90 nm. AFM images of several samples both in amplitude modulation (tapping-mode) and in frequency modulation were obtained.

  13. A subsurface add-on for standard atomic force microscopes.

    Science.gov (United States)

    Verbiest, G J; van der Zalm, D J; Oosterkamp, T H; Rost, M J

    2015-03-01

    The application of ultrasound in an Atomic Force Microscope (AFM) gives access to subsurface information. However, no commercially AFM exists that is equipped with this technique. The main problems are the electronic crosstalk in the AFM setup and the insufficiently strong excitation of the cantilever at ultrasonic (MHz) frequencies. In this paper, we describe the development of an add-on that provides a solution to these problems by using a special piezo element with a lowest resonance frequency of 2.5 MHz and by separating the electronic connection for this high frequency piezo element from all other connections. In this sense, we support researches with the possibility to perform subsurface measurements with their existing AFMs and hopefully pave also the way for the development of a commercial AFM that is capable of imaging subsurface features with nanometer resolution.

  14. A subsurface add-on for standard atomic force microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Verbiest, G. J., E-mail: Verbiest@physik.rwth-aachen.de [JARA-FIT and II. Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Zalm, D. J. van der; Oosterkamp, T. H.; Rost, M. J., E-mail: Rost@physics.leidenuniv.nl [Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands)

    2015-03-15

    The application of ultrasound in an Atomic Force Microscope (AFM) gives access to subsurface information. However, no commercially AFM exists that is equipped with this technique. The main problems are the electronic crosstalk in the AFM setup and the insufficiently strong excitation of the cantilever at ultrasonic (MHz) frequencies. In this paper, we describe the development of an add-on that provides a solution to these problems by using a special piezo element with a lowest resonance frequency of 2.5 MHz and by separating the electronic connection for this high frequency piezo element from all other connections. In this sense, we support researches with the possibility to perform subsurface measurements with their existing AFMs and hopefully pave also the way for the development of a commercial AFM that is capable of imaging subsurface features with nanometer resolution.

  15. A Conceptual Atomic Force Microscope using LEGO for Nanoscience Education

    Directory of Open Access Journals (Sweden)

    Tsung-Han Hsieh

    2014-05-01

    Full Text Available A lack of effective educational materials is limited general public awareness of, and interest in, nanoscience. This paper presents a conceptual atomic force microscope (AFM model built by using the LEGO® MINDSTORMS series. AFMs are perhaps one of the most fundamental and widely-used instruments in nanoscience and nanotechnology, thus the introduction of this LEGO® AFM should be beneficial to nanoscience education. Programmed in LabVIEW, this LEGO® model has the ability to scan the samples and construct a three-dimensional (3D surface graphs of the sample, based on the mechanism used for AFM. With this LEGO® AFM, the students can directly access nanoscience concepts through hands-on experience constructing an AFM model. This interaction will lead to a better understanding of nanoscience principles, and motivate learners to further explore both the theoretical and experimental aspects of the domain.

  16. Electron microscopic observation of preretinal membranes.

    Science.gov (United States)

    Yamamoto, T; Yamashita, H; Hori, S

    1989-01-01

    In this report, membranes removed during vitrectomy were observed by various methods of electron microscopy to determine their three-dimensional structure and the mechanism of the contraction of preretinal membranes. The vitreous side surface of the preretinal membranes was covered by two types of flat cells, cells with long, extended processes and cells in a pavement arrangement. The lamellae of the flat cells in the internal structures of the preretinal membranes were also observed. In each lamella, the cells appeared to have a connection with each other and formed networks. The retinal side surface of the preretinal membranes was smooth and acellular. The glycerinated preretinal membranes were exposed to ATP and Mg2+, which induced the contraction of the component cells of the preretinal membranes. When the cells on the vitreous side surface of the preretinal membranes contracted, the intercellular connections among them appeared to be preserved.

  17. Investigation of penetration force of living cell using an atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Eun Young; Kim, Young Tae; Kim, Dae Eun [Yonsei University, Seoul (Korea, Republic of)

    2009-07-15

    Recently, the manipulation of a single cell has been receiving much attention in transgenesis, in-vitro fertilization, individual cell based diagnosis, and pharmaceutical applications. As these techniques require precise injection and manipulation of cells, issues related to penetration force arise. In this work the penetration force of living cell was studied using an atomic force microscope (AFM). L929, HeLa, 4T1, and TA3 HA II cells were used for the experiments. The results showed that the penetration force was in the range of 2{approx}22 nN. It was also found that location of cell penetration and stiffness of the AFM cantilever affected the penetration force significantly. Furthermore, double penetration events could be detected, due to the multi-membrane layers of the cell. The findings of this work are expected to aid in the development of precision micro-medical instruments for cell manipulation and treatment

  18. Development of Atomic Force Microscope for Arthroscopic Knee Cartilage Inspection

    Science.gov (United States)

    Imer, Raphaël; Akiyama, Terunobu; de Rooij, Nicolaas F.; Stolz, Martin; Aebi, Ueli; Friederich, Niklaus F.; Koenig, Uwe; Wirz, Dieter; Daniels, A. U.; Staufer, Urs

    2006-03-01

    A recent study, based on ex vivo unconfined compression testing of normal, diseased, and enzymatically altered cartilage, revealed that a scanning force microscope (SFM), used as a nano-intender, is sensitive enough to enable measurement of alterations in the biomechanical properties of cartilage. Based on these ex vivo measurements, we have designed a quantitative diagnosis tool, the scanning force arthroscope (SFA), able to perform in vivo measurements during a standard arthroscopic procedure. For stabilizing and positioning the instrument relative to the surface under investigation, a pneumatic system has been developed. A segmented piezoelectric tube was used to perform the indentation displacement, and a pyramidal nanometer-scale silicon tip mounted on a cantilever with an integrated deflection sensor measured the biomechanical properties of cartilage. Mechanical means were designed to protect the fragile cantilever during the insertion of the instrument into the knee joint. The stability of the pneumatic stage was checked with a prototype SFA. In a series of tests, load-displacement curves were recorded in a knee phantom and, more recently, in a pig’s leg.

  19. Visualization of Cellulose Microfibrils of Phyllostachys pubescens Fibers with Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purposes. The first method was chemical maceration with a mixture of hydrogen peroxide and glacial acetic acid, through which the obtained fibers were suitable for observing the orientation of CMF in the primary wal1. The other method was to prepare tangential microtomed sections with a thickness o...

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

    Directory of Open Access Journals (Sweden)

    Jana ANDZANE

    2012-06-01

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

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

    DEFF Research Database (Denmark)

    Jensen, Flemming

    1993-01-01

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

  2. Force measurements with the atomic force microscope: Technique, interpretation and applications

    Science.gov (United States)

    Butt, Hans-Jürgen; Cappella, Brunero; Kappl, Michael

    2005-10-01

    The atomic force microscope (AFM) is not only a tool to image the topography of solid surfaces at high resolution. It can also be used to measure force-versus-distance curves. Such curves, briefly called force curves, provide valuable information on local material properties such as elasticity, hardness, Hamaker constant, adhesion and surface charge densities. For this reason the measurement of force curves has become essential in different fields of research such as surface science, materials engineering, and biology. Another application is the analysis of surface forces per se. Some of the most fundamental questions in colloid and surface science can be addressed directly with the AFM: What are the interactions between particles in a liquid? How can a dispersion be stabilized? How do surfaces in general and particles in particular adhere to each other? Particles and surfaces interactions have major implications for friction and lubrication. Force measurements on single molecules involving the rupture of single chemical bonds and the stretching of polymer chains have almost become routine. The structure and properties of confined liquids can be addressed since force measurements provide information on the energy of a confined liquid film. After the review of Cappella [B. Cappella, G. Dietler, Surf. Sci. Rep. 34 (1999) 1-104] 6 years of intense development have occurred. In 1999, the AFM was used only by experts to do force measurements. Now, force curves are used by many AFM researchers to characterize materials and single molecules. The technique and our understanding of surface forces has reached a new level of maturity. In this review we describe the technique of AFM force measurements. Important experimental issues such as the determination of the spring constant and of the tip radius are discussed. Current state of the art in analyzing force curves obtained under different conditions is presented. Possibilities, perspectives but also open questions and

  3. Microscopic analysis of sharp force trauma in bone and cartilage: a validation study.

    Science.gov (United States)

    Crowder, Christian; Rainwater, Christopher W; Fridie, Jeannette S

    2013-09-01

    Sharp force trauma research lacks agreement on reported error rates for correctly identifying toolmark characteristics on bone and cartilage. This study provides error rates for determining blade class (serrated, partially serrated, nonserrated) and type of edge bevel (left, right, even). Three analysts examined cuts to a wax medium, cartilage, and bone using two types of microscopes. Additionally, the observers examined impressions taken from the wax medium and the cartilage. Overall, a total of 504 observations were performed. Serrated blades were distinguishable from nonserrated blades due to their patterned striations. Some difficulties were encountered in distinguishing serrated and partially serrated blades; however, when these groups were considered together as one classification type (serrated), classification accuracy improved from 79% to 96%. Classification accuracy for edge bevel was 65%. Error rates were similar when comparing direct observation of the cut marks versus indirect observation (impressions). Additionally, the type of microscope used did not affect error rates.

  4. Investigation of structural change of purple membrane in storage by transmission electron microscope and atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The structural change of purple membrane during storage has been investigated by means of transmission electron microscope and atomic force microscope. It is found that many liposomes have spontaneously evolved from the purple membrane sheets isolated three years ago. The membrane proteins on the liposomes, bacteriorhodopsin, are still presented as trimers in 2-D hexagonal structure, which is the same as that in natural cell membrane. However, the cytoplasmic surface of purple membrane faced outside on the liposomes.

  5. Harmonic force microscope: A new tool for biomolecular identification and material characterization based on nanomechanical measurements

    Science.gov (United States)

    Sahin, Ozgur

    At the molecular level, physical and chemical properties of materials are tightly coupled to the mechanical properties. The potential of mechanics for interacting with matter at the nanoscale has been largely unexplored due to lack of instruments capable of performing mechanical measurements at nanometer length scales. This thesis describes nanomechanical sensing techniques and applications based on time-resolved tip-sample force measurements in tapping-mode atomic force microscopy. Tapping mode is the most successful operation mode of atomic force microscopes. Theoretical calculations presented in the first part of this thesis show that time variations of the tip-sample forces in the tapping-mode depend on the physical and chemical properties of the sample and therefore, have the potential to be used for nanomechanical measurements. Unfortunately, the force-sensing probe of the tapping-mode atomic force microscope, the vibrating cantilever, is limited in its response to the variations of forces in time within a period of oscillations. We are describing two types of special micromachined cantilevers that enable measurements of time variations of tip-sample forces: the harmonic cantilever and the coupled torsional cantilever. These special cantilevers allow sensitive mechanical measurements at the nanoscale and single molecular level. The operation of these cantilevers does not require any modifications to the existing atomic force microscopy systems. With the nanomechanical sensing techniques we have developed, we investigated phase transformations of sub-micron domains of composite polymers and observed their glass transitions for the first time. Conventional measurements on bulk properties of these samples do not provide information on the physical changes at the nanoscale. Studies on nucleic acids attached to a surface, a configuration commonly used in DNA microarray technology, showed that the hybridized DNA molecules can be detected at the single molecule

  6. Contact resonances of U-shaped atomic force microscope probes

    Energy Technology Data Exchange (ETDEWEB)

    Rezaei, E.; Turner, J. A., E-mail: jaturner@unl.edu [Mechanical and Materials Engineering, University of Nebraska-Lincoln, W342 Nebraska Hall, Lincoln, Nebraska 68588 (United States)

    2016-01-21

    Recent approaches used to characterize the elastic or viscoelastic properties of materials with nanoscale resolution have focused on the contact resonances of atomic force microscope (CR-AFM) probes. The experiments for these CR-AFM methods involve measurement of several contact resonances from which the resonant frequency and peak width are found. The contact resonance values are then compared with the noncontact values in order for the sample properties to be evaluated. The data analysis requires vibration models associated with the probe during contact in order for the beam response to be deconvolved from the measured spectra. To date, the majority of CR-AFM research has used rectangular probes that have a relatively simple vibration response. Recently, U-shaped AFM probes have created much interest because they allow local sample heating. However, the vibration response of these probes is much more complex such that CR-AFM is still in its infancy. In this article, a simplified analytical model of U-shaped probes is evaluated for contact resonance applications relative to a more complex finite element (FE) computational model. The tip-sample contact is modeled using three orthogonal Kelvin-Voigt elements such that the resonant frequency and peak width of each mode are functions of the contact conditions. For the purely elastic case, the frequency results of the simple model are within 8% of the FE model for the lowest six modes over a wide range of contact stiffness values. Results for the viscoelastic contact problem for which the quality factor of the lowest six modes is compared show agreement to within 13%. These results suggest that this simple model can be used effectively to evaluate CR-AFM experimental results during AFM scanning such that quantitative mapping of viscoelastic properties may be possible using U-shaped probes.

  7. Effects of Microscopic Three-body Forces in Asymmetric Nuclear Matter

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The efiects of microscopic three-body forces on the equatioil of state(EOS)and the single particle properties of isospin asymmetric nuclear matter have been studied within Brueckner-Hartree-Fock framework~[1]The microscopic three-body force model constructed from meson exchange current approach in Ref.~[2] has been extended to isospin asymmetric nuclear matter

  8. Macroscopic and microscopic observations of needle insertion into gels

    NARCIS (Netherlands)

    Veen, van Youri R.J.; Jahya, Alex; Misra, Sarthak

    2012-01-01

    Needle insertion into soft tissue is one of the most common medical interventions. This study provides macroscopic and microscopic observations of needle–gel interactions. A gelatin mixture is used as a soft-tissue simulant. For the macroscopic studies, system parameters, such as insertion velocity,

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

    Science.gov (United States)

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

    2009-08-01

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

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

    KAUST Repository

    Kwek, Jin Wang

    2011-07-01

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

  11. [A scanning electron microscope observation of Dictyocaulus filaria.].

    Science.gov (United States)

    Yildiz, Kader; Cavuşoğlu, Kültiğin

    2005-01-01

    In this study, D. filaria causing parasitic bronchopneumonia in sheep was observed using a scanning electron microscope. This parasite belongs to the Trichostrongyloidea super family. The oral opening of D. filaria was observed to be small and circular in shape. Lips were not evident. Any difference between anterior ends of male and female parasites was not observed in present study. In the female parasite, the anus was seen as a fissure in shape. The post anal papilla was seen near the posterior end of the female. Spicula and cloacae of male parasites were observed.

  12. Strong electromechanical coupling of an atomic force microscope cantilever to a quantum dot.

    Science.gov (United States)

    Bennett, Steven D; Cockins, Lynda; Miyahara, Yoichi; Grütter, Peter; Clerk, Aashish A

    2010-01-08

    We present theoretical and experimental results on the mechanical damping of an atomic force microscope cantilever strongly coupled to a self-assembled InAs quantum dot. When the cantilever oscillation amplitude is large, its motion dominates the charge dynamics of the dot which in turn leads to nonlinear, amplitude-dependent damping of the cantilever. We observe highly asymmetric line shapes of Coulomb blockade peaks in the damping that reflect the degeneracy of energy levels on the dot. Furthermore, we predict that excited state spectroscopy is possible by studying the damping versus oscillation amplitude, in analogy with varying the amplitude of an ac gate voltage.

  13. Visualization of interaction between ribosome-inactivating proteins and supercoiled DNA with an atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    吴晓华; 刘望夷; 欧阳振乾; 李民乾

    1997-01-01

    The interaction between ribosome-inactivating proteins (RIPs) and supercoiled DNA was observed with an atomic force microscope (AFM). It was found that RIPs can bind to both supercoiled DNA and the unwound double stranded loop region in supercoiled DNA. The RIPs hound to the supercoils can induce the conformational change of supercoiled DNA. Furthermore, the supercoiled DNA was relaxed and cleaved into nick or linear form by RIPs. It indicated that RIP seemed to be a supercoil-dependent DNA binding protein and exhibited the activity of su-percoil-dependent DNA endonuclease.

  14. A variable-temperature nanostencil compatible with a low-temperature scanning tunneling microscope/atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Steurer, Wolfram, E-mail: wst@zurich.ibm.com; Gross, Leo; Schlittler, Reto R.; Meyer, Gerhard [IBM Research-Zurich, 8803 Rüschlikon (Switzerland)

    2014-02-15

    We describe a nanostencil lithography tool capable of operating at variable temperatures down to 30 K. The setup is compatible with a combined low-temperature scanning tunneling microscope/atomic force microscope located within the same ultra-high-vacuum apparatus. The lateral movement capability of the mask allows the patterning of complex structures. To demonstrate operational functionality of the tool and estimate temperature drift and blurring, we fabricated LiF and NaCl nanostructures on Cu(111) at 77 K.

  15. A histopathological and electron microscopical observation of urticaria pigmentosa

    Directory of Open Access Journals (Sweden)

    Ke-jian Zhu

    1990-01-01

    Full Text Available In a case of urticaria pigmentosa, histopathological and electron microscopical observation of skin lesions before and after dermatographism were compared. The results showed that the shape, membranes, nuclei and granules of mast cells in the lesions before and after dermatographism are different. The prognosis, the clinical significance of dermato-graphism test and the pattern of degranulation in urticaria pigmentosa are discussed.

  16. Relaxation of a simulated lipid bilayer vesicle compressed by an atomic force microscope

    Science.gov (United States)

    Barlow, Ben M.; Bertrand, Martine; Joós, Béla

    2016-11-01

    Using coarse-grained molecular dynamics simulations, we study the relaxation of bilayer vesicles, uniaxially compressed by an atomic force microscope cantilever. The relaxation time exhibits a strong force dependence. Force-compression curves are very similar to recent experiments wherein giant unilamellar vesicles were compressed in a nearly identical manner.

  17. US Air Force Balloon Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Worksheets containing pilot balloon data computed from releases at Air Force stations in the western United States. Elevation and azimuth angles are used to compute...

  18. A combined near field optical and force microscope

    NARCIS (Netherlands)

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

    1993-01-01

    Scanning near field optical microscopy (SNOM) is the optical alternative of the scanning probe microscopical techniques which enables a lateral resolution down to about 10 nm, unlimited by diffraction. Moreover, the potential of non- destructive imaging of chemical and biological samples with nanome

  19. Accurate measurement of microscopic forces and torques using optical tweezers

    CSIR Research Space (South Africa)

    McLaren, M

    2011-09-01

    Full Text Available It is now well known that matter may be trapped by optical fields with high intensity gradients. Once trapped, it is then possible to manipulate microscopic particles using such optical fields, in so-called optical tweezers. Such optical trapping...

  20. Development of nanomanipulator using a high-speed atomic force microscope coupled with a haptic device

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, F., E-mail: tmfiwat@ipc.shizuoka.ac.jp [Faculty of Engineering, Shizuoka University, Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Research Institute of Electronics, Shizuoka University, Johoku, Naka-ku, Hamamatsu 432-8011 (Japan); Ohashi, Y.; Ishisaki, I. [Faculty of Engineering, Shizuoka University, Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Picco, L.M. [H Will Physics Laboratory and IRC in Nanotechnology, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Ushiki, T. [Graduate School of Medical and Dental Sciences, Niigata University, Asahimachidori, Niigata, 951-8122 (Japan)

    2013-10-15

    The atomic force microscope (AFM) has been widely used for surface fabrication and manipulation. However, nanomanipulation using a conventional AFM is inefficient because of the sequential nature of the scan-manipulation scan cycle, which makes it difficult for the operator to observe the region of interest and perform the manipulation simultaneously. In this paper, a nanomanipulation technique using a high-speed atomic force microscope (HS-AFM) is described. During manipulation using the AFM probe, the operation is periodically interrupted for a fraction of a second for high-speed imaging that allows the topographical image of the manipulated surface to be periodically updated. With the use of high-speed imaging, the interrupting time for imaging can be greatly reduced, and as a result, the operator almost does not notice the blink time of the interruption for imaging during the manipulation. This creates a more intuitive interface with greater feedback and finesse to the operator. Nanofabrication under real-time monitoring was performed to demonstrate the utility of this arrangement for real-time nanomanipulation of sample surfaces under ambient conditions. Furthermore, the HS-AFM is coupled with a haptic device for the human interface, enabling the operator to move the HS-AFM probe to any position on the surface while feeling the response from the surface during the manipulation. - Highlights: • A nanomanipulater based on a high-speed atomic force microscope was developped. • High-speed imaging provides a valuable feedback during the manipulation operation. • Operator can feel the response from the surface via a haptic device during manipulation. • Nanofabrications under real-time monitoring were successfully performed.

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

    Science.gov (United States)

    Jones, C. N.; Goncalves, J.

    2010-01-01

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

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

    Science.gov (United States)

    Jones, C. N.; Goncalves, J.

    2010-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-01

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

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

    CERN Document Server

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

    2000-01-01

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

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

    Science.gov (United States)

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

    2017-06-01

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

  6. Higher Harmonics Generation in Tapping Mode Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    LI Yuan; QIAN Jian-Qiang

    2009-01-01

    The contribution of higher harmonics to the movement of a micro rectangular cantilever in tapping mode AFM is investigated. The dependence between the phase lag of the higher harmonic components and tip-sample separation are found to be an order of magnitude higher than the base one, reflecting an increasing sensitivity to local variations of surface properties compared to the normal phase signal.The strong correlation between the higher harmonic amplitude and average sample deformation implies that the higher harmonic amplitude can be taken to monitor the tapping force or as feedback variable to fulfill a constant repulsive force mode.

  7. Indirect identification and compensation of lateral scanner resonances in atomic force microscopes.

    Science.gov (United States)

    Burns, D J; Youcef-Toumi, K; Fantner, G E

    2011-08-05

    Improving the imaging speed of atomic force microscopy (AFM) requires accurate nanopositioning at high speeds. However, high speed operation excites resonances in the AFM's mechanical scanner that can distort the image, and therefore typical users of commercial AFMs elect to operate microscopes at speeds below which scanner resonances are observed. Although traditional robust feedforward controllers and input shaping have proven effective at minimizing the influence of scanner distortions, the lack of direct measurement and use of model-based controllers have required disassembling the microscope to access lateral scanner motion with external sensors in order to perform a full system identification experiment, which places excessive demands on routine microscope operators. Further, since the lightly damped instrument dynamics often change from experiment to experiment, model-based controllers designed from offline system identification experiments must trade off high speed performance for robustness to modeling errors. This work represents a new way to automatically characterize the lateral scanner dynamics without addition of lateral sensors, and shape the commanded input signals in such a way that disturbing dynamics are not excited. Scanner coupling between the lateral and out-of-plane directions is exploited and used to build a minimal model of the scanner that is also sufficient to describe the nature of the distorting resonances. This model informs the design of an online input shaper used to suppress spectral components of the high speed command signals. The method presented is distinct from alternative approaches in that neither an information-complete system identification experiment nor microscope modification are required. Because the system identification is performed online immediately before imaging, no tradeoff of performance is required. This approach has enabled an increase in the scan rates of unmodified commercial AFMs from 1-4 lines s(-1) to

  8. Corneal Cell Morphology in Keratoconus: A Confocal Microscopic Observation

    Science.gov (United States)

    Ghosh, Somnath; Mutalib, Haliza Abdul; Kaur, Sharanjeet; Ghoshal, Rituparna; Retnasabapathy, Shamala

    2017-01-01

    Purpose To evaluate corneal cell morphology in patients with keratoconus using an in vivo slit scanning confocal microscope. Methods A cross-sectional study was conducted to evaluate the corneal cell morphology of 47 keratoconus patients and 32 healthy eyes without any ocular disease. New keratoconus patients with different disease severities and without any other ocular co-morbidity were recruited from the ophthalmology department of a public hospital in Malaysia from June 2013 to May 2014. Corneal cell morphology was evaluated using an in vivo slit-scanning confocal microscope. Qualitative and quantitative data were analysed using a grading scale and the Nidek Advanced Visual Information System software, respectively. Results The corneal cell morphology of patients with keratoconus was significantly different from that of healthy eyes except in endothelial cell density (P = 0.072). In the keratoconus group, increased level of stromal haze, alterations such as the elongation of keratocyte nuclei and clustering of cells at the anterior stroma, and dark bands in the posterior stroma were observed with increased severity of the disease. The mean anterior and posterior stromal keratocyte densities and cell areas among the different stages of keratoconus were significantly different (P 0.05) among the three stages of keratoconus. Conclusion Confocal microscopy observation showed significant changes in corneal cell morphology in keratoconic cornea from normal healthy cornea. Analysis also showed significant changes in different severities of keratoconus. Understanding the corneal cell morphology changes in keratoconus may help in the long-term monitoring and management of keratoconus. PMID:28894403

  9. Model based control of dynamic atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chibum [Department of Mechanical System Design Engineering, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Salapaka, Srinivasa M., E-mail: salapaka@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2015-04-15

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H{sub ∞} control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments.

  10. Model based control of dynamic atomic force microscope.

    Science.gov (United States)

    Lee, Chibum; Salapaka, Srinivasa M

    2015-04-01

    A model-based robust control approach is proposed that significantly improves imaging bandwidth for the dynamic mode atomic force microscopy. A model for cantilever oscillation amplitude and phase dynamics is derived and used for the control design. In particular, the control design is based on a linearized model and robust H(∞) control theory. This design yields a significant improvement when compared to the conventional proportional-integral designs and verified by experiments.

  11. Observation of Materials Processes in Liquids in the Electron Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chong M.; Liao, Honggang; Ross, Frances M.

    2015-01-01

    Materials synthesis and the functioning of devices often indispensably involve liquid media. But direct visualization of dynamic process in liquids, especially with high spatial and temporal resolution, has been challenging. For solid materials, advances in aberration corrected electron microscopy have made observation of atomic level features a routine practice. Here we discuss the extent to which one can take advantage of the resolution of modern electron microscopes to image phenomenon occuring in liquids. We will describe the fundamentals of two different experimental approaches, closed and open liquid cells. We will illustrate the capabilities of each approach by considering processes in batteries and nucleation and growth of nanoparticles from solution. We conclude that liquid cell electron microscopy appears to be duly fulfilling its role for in situ studies of nanoscale processes in liquids, revealing physical and chemical processes otherwise difficult to observe.

  12. Massively Parallel Atomic Force Microscope with Digital Holographic Readout

    Energy Technology Data Exchange (ETDEWEB)

    Sache, L [Laboratory of Robotic Systems, Ecole Polytechnique Federale de Lausanne, EPFLSRO1, Station 9, CH-1015 Lausanne (Switzerland); Kawakatsu, H [Institute of Industrial Science, University of Tokyo, Tokyo (Japan); Emery, Y [Lyncee Tec SA, PSE-A, CH-1015 Lausanne (Switzerland); Bleuler, H [Laboratory of Robotic Systems, Ecole Polytechnique Federale de Lausanne, EPFLSRO1, Station 9, CH-1015 Lausanne (Switzerland)

    2007-03-15

    Massively Parallel Scanning Probe Microscopy is an obvious path for data storage (E Grochowski, R F Hoyt, Future Trends in Hard disc Drives, IEEE Trans. Magn. 1996, 32, 1850- 1854; J L Griffin, S W Schlosser, G R Ganger and D F Nagle, Modeling and Performance of MEMS-Based Storage Devices, Proc. ACM SIGMETRICS, 2000). Current experimental systems still lay far behind Hard Disc Drive (HDD) or Digital Video Disk (DVD), be it in access speed, data throughput, storage density or cost per bit. This paper presents an entirely new approach with the promise to break several of these barriers. The key idea is readout of a Scanning Probes Microscope (SPM) array by Digital Holographic Microscopy (DHM). This technology directly gives phase information at each pixel of a CCD array. This means that no contact line to each individual SPM probes is needed. The data is directly available in parallel form. Moreover, the optical setup needs in principle no expensive components, optical (or, to a large extent, mechanical) imperfections being compensated in the signal processing, i.e. in electronics. This gives the system the potential for a low cost device with fast Terabit readout capability.

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

    OpenAIRE

    Andreae, M. O.; G. Helas

    2008-01-01

    We show that atomic force microscopy (AFM) phase images can reveal surface features of soil dust particles, which are not evident using other microscopic methods. The non-contact AFM method is able to resolve topographical structures in the nanometer range as well as to uncover repulsive atomic forces and attractive van der Waals' forces, and thus gives insight to surface properties. Though the method does not allow quantitative assignment in terms of chemical compound description, it clearly...

  14. Characterization of Akiyama probe applied to dual-probes atomic force microscope

    Science.gov (United States)

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

    2016-10-01

    The measurement of nano-scale line-width has always been important and difficult in the field of nanometer measurements, while the rapid development of integrated circuit greatly raises the demand again. As one kind of scanning probe microscope (SPM), atomic force microscope (AFM) can realize quasi three-dimensional measurement, which is widely used in nanometer scale line-width measurement. Our team researched a dual-probes atomic force microscope, which can eliminate the prevalent effect of probe width on measurement results. In dual-probes AFM system, a novel head are newly designed. A kind of self-sensing and self-exciting probes which is Nanosensors cooperation's patented probe—Akiyama probe, is used in this novel head. The Akiyama probe applied to dual-probe atomic force microscope is one of the most important issues. The characterization of Akiyama probe would affect performance and accuracy of the whole system. The fundamental features of the Akiyama probe are electrically and optically characterized in "approach-withdraw" experiments. Further investigations include the frequency response of an Akiyama probe to small mechanical vibrations externally applied to the tip and the effective loading force yielding between the tip and the sample during the periodic contact. We hope that the characterization of the Akiyama probe described in this paper will guide application for dual-probe atomic force microscope.

  15. High-Throughput Atomic Force Microscopes Operating in Parallel

    CERN Document Server

    Sadeghian, H; Dekker, B; Winters, J; Bijnagte, T; Rijnbeek, R

    2016-01-01

    Atomic force microscopy (AFM) is an essential nanoinstrument technique for several applications such as cell biology and nanoelectronics metrology and inspection. The need for statistically significant sample sizes means that data collection can be an extremely lengthy process in AFM. The use of a single AFM instrument is known for its very low speed and not being suitable for scanning large areas, resulting in very-low-throughput measurement. We address this challenge by parallelizing AFM instruments. The parallelization is achieved by miniaturizing the AFM instrument and operating many of them simultaneously. This nanoinstrument has the advantages that each miniaturized AFM can be operated independently and that the advances in the field of AFM, both in terms of speed and imaging modalities, can be implemented more easily. Moreover, a parallel AFM instrument also allows one to measure several physical parameters simultaneously; while one instrument measures nano-scale topography, another instrument can meas...

  16. Atomic force microscope study of three-dimensional nanostructure sidewalls

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Muhammad Mustafa [SEMATECH, 2706 Montopolis Drive, Austin, TX 78741 (United States); Gondran, Carolyn F H [Advanced Technology Development Facility, 2706 Montopolis Drive, Austin, TX 78741 (United States); Michelson, Diane K [International SEMATECH Manufacturing Initiative, 2706 Montopolis Drive, Austin, TX 78741 (United States)

    2007-08-22

    Next generation planar and non-planar complementary metal oxide semiconductor (CMOS) structures are three-dimensional nanostructures with multi-layer stacks that can contain films thinner than ten atomic layers. The high resolution of transmission electron microscopy (TEM) is typically chosen for studying properties of these stacks such as film thickness, interface and interfacial roughness. However, TEM sample preparation is time-consuming and destructive, and TEM analysis is expensive and can provide problematic results for surface and interface roughness. Therefore, in this paper, we present the use of direct measurements of sidewall surface structures by conventional atomic force microscopy (AFM) as an alternative or complementary method for studying multi-layer film stacks and as the preferred method for studying FinFET sidewall surface roughness. In addition to these semiconductor device applications, this AFM sidewall measurement technique could be used for other three-dimensional nanostructures.

  17. Lipid memberane:inelastic deformation of surface structure by an atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The stability of the 1,2-Dioleoyl-sn-Glycero-3-[phospho-rac-1-Glycerol-Na] liposome in the liquid crystalline state have been investigated using an atomic force microscope(AFM),We have observed the inelastic deformation of the sample surface,The AFM tip causes persistent deformation of the surface of the lipid membrane,in which some of the lipid molecules are eventually pushed or dragged by the AFM tip.The experiment shows how the surface structure of the lipid membrane can be created by the interaction between the AFM tip and lipid membrane.When the operating force exceeds 10-8N,it leads to large deformations of the surface.A squareregion of about 1×1um2 is created by the scanning probe on the surface,When the operating force is between 10-11N and 10-8N,it can image the topography of the surface of the lipid membrane.The stability of the sample is related to the concentration of the medium in which the sample is prepared.

  18. In situ atomic force microscope imaging of supported lipid bilayers

    DEFF Research Database (Denmark)

    Kaasgaard, Thomas; Leidy, Chad; Ipsen, John Hjorth

    2001-01-01

    In situ AFM images of phospholipase A/sub 2/ (PLA/sub 2/) hydrolysis of mica-supported one- and two-component lipid bilayers are presented. For one-component DPPC bilayers an enhanced enzymatic activity is observed towards preexisting defects in the bilayer. Phase separation is observed in two......-component DMPC-DSPC bilayers and a remarkable enhanced hydrolytic activity of the PLA/sub 2/-enzyme for the DMPC-rich phase is seen. Furthermore, in a supported double bilayer system a characteristic ripple structure, most likely related to the formation of the P/sub beta /-ripple phase is observed....

  19. Scanning force microscope for in situ nanofocused X-ray diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Zhe, E-mail: zhe.ren@im2np.fr; Mastropietro, Francesca; Davydok, Anton [Aix-Marseille Université, CNRS, Faculté des Sciences, Campus de Saint-Jérôme, Avenue Escadrille Normandie Niemen – Case 142, F-13397 Marseille (France); Langlais, Simon [Grenoble Institute of Technology and CNRS, BP 75, F-38402 Saint-Martin d’Hères Cedex (France); Richard, Marie-Ingrid [Aix-Marseille Université, CNRS, Faculté des Sciences, Campus de Saint-Jérôme, Avenue Escadrille Normandie Niemen – Case 142, F-13397 Marseille (France); European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, BP 220, 38043 Grenoble (France); Furter, Jean-Jacques; Thomas, Olivier [Aix-Marseille Université, CNRS, Faculté des Sciences, Campus de Saint-Jérôme, Avenue Escadrille Normandie Niemen – Case 142, F-13397 Marseille (France); Dupraz, Maxime; Verdier, Marc; Beutier, Guillaume [Grenoble Institute of Technology and CNRS, BP 75, F-38402 Saint-Martin d’Hères Cedex (France); Boesecke, Peter [European Synchrotron Radiation Facility (ESRF), 6 rue Jules Horowitz, BP 220, 38043 Grenoble (France); Cornelius, Thomas W. [Aix-Marseille Université, CNRS, Faculté des Sciences, Campus de Saint-Jérôme, Avenue Escadrille Normandie Niemen – Case 142, F-13397 Marseille (France)

    2014-08-06

    An atomic force microscope has been developed for combination with sub-micrometer focused X-ray diffraction at synchrotron beamlines and in situ mechanical tests on single nanostructures. A compact scanning force microscope has been developed for in situ combination with nanofocused X-ray diffraction techniques at third-generation synchrotron beamlines. Its capabilities are demonstrated on Au nano-islands grown on a sapphire substrate. The new in situ device allows for in situ imaging the sample topography and the crystallinity by recording simultaneously an atomic force microscope (AFM) image and a scanning X-ray diffraction map of the same area. Moreover, a selected Au island can be mechanically deformed using the AFM tip while monitoring the deformation of the atomic lattice by nanofocused X-ray diffraction. This in situ approach gives access to the mechanical behavior of nanomaterials.

  20. High-throughput atomic force microscopes operating in parallel

    Science.gov (United States)

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

    2017-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-15

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

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

    DEFF Research Database (Denmark)

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

    1999-01-01

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

  3. Microscopic Three-Body Force Effect on Nucleon-Nucleon Cross Sections in Symmetric Nuclear Matter

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-Fei; ZUO Wei; Lombardo Umberto; LI Zeng-Hua; LI Jun-Qing

    2008-01-01

    We provide a microscopic calculation of neutron-proton and proton-proton cross sections in symmetric nuclear matter at various densities, using the Brueckner-Hartree-Fock approximation scheme with the Argonne V14 potential including the contribution of microscopic three-body force. We investigate separately the effects of three-body force on the effective mass and on the scattering amplitude. In the present calculation, the rearrangement contribution of three-body force is considered, which will reduce the neutron and proton effective mass, and depress the amplitude of cross section. The effect of three body force is shown to be repulsive, especially in high densities and large momenta, which will suppress the cross section markedly.

  4. Refined tip preparation by electrochemical etching and ultrahigh vacuum treatment to obtain atomically sharp tips for scanning tunneling microscope and atomic force microscope.

    Science.gov (United States)

    Hagedorn, Till; El Ouali, Mehdi; Paul, William; Oliver, David; Miyahara, Yoichi; Grütter, Peter

    2011-11-01

    A modification of the common electrochemical etching setup is presented. The described method reproducibly yields sharp tungsten tips for usage in the scanning tunneling microscope and tuning fork atomic force microscope. In situ treatment under ultrahigh vacuum (p ≤10(-10) mbar) conditions for cleaning and fine sharpening with minimal blunting is described. The structure of the microscopic apex of these tips is atomically resolved with field ion microscopy and cross checked with field emission.

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

    Directory of Open Access Journals (Sweden)

    Andrzej Kurenda

    2013-09-01

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

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

    Science.gov (United States)

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

    2017-06-01

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

  7. Lipid membrane: inelastic deformation of surface structure by an atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    张静; 孙润广

    2002-01-01

    The stability of the 1,2-Dioleoyl-sn-Glycero-3-[phospho-rac-1-Glycerol-Na] liposome in the liquid crystalline statehave been investigated using an atomic force microscope (AFM). We have observed the inelastic deformation of thesample surface. The AFM tip causes persistent deformation of the surface of the lipid membrane, in which some of thelipid molecules are eventually pushed or dragged by the AFM tip. The experiment shows how the surface structure ofthe lipid membrane can be created by the interaction between the AFM tip and lipid membrane. When the operatingforce exceeds 10-8 N, it leads to large deformations of the surface. A square region of about 1×1μm2 is created by thescanning probe on the surface. When the operating force is between 10-11N and 10-8N, it can image the topographyof the surface of the lipid membrane. The stability of the sample is related to the concentration of the medium in whichthe sample is prepared.

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

    Science.gov (United States)

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

    2011-10-18

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

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

    Science.gov (United States)

    Planinsic, Gorazd; Kovac, Janez

    2008-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Science.gov (United States)

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

    2015-01-01

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

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

    DEFF Research Database (Denmark)

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

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning...

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

    Science.gov (United States)

    Planinsic, Gorazd; Kovac, Janez

    2008-01-01

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

  14. Observation of the thermal Casimir force

    CERN Document Server

    Sushkov, A O; Dalvit, D A R; Lamoreaux, S K

    2010-01-01

    Quantum theory predicts the existence of the Casimir force between macroscopic bodies, due to the zero-point energy of electromagnetic field modes around them. This quantum fluctuation-induced force has been experimentally observed for metallic and semiconducting bodies, although the measurements to date have been unable to clearly settle the question of the correct low-frequency form of the dielectric constant dispersion (the Drude model or the plasma model) to be used for calculating the Casimir forces. At finite temperature a thermal Casimir force, due to thermal, rather than quantum, fluctuations of the electromagnetic field, has been theoretically predicted long ago. Here we report the experimental observation of the thermal Casimir force between two gold plates. We measured the attractive force between a flat and a spherical plate for separations between 0.7 $\\mu$m and 7 $\\mu$m. An electrostatic force caused by potential patches on the plates' surfaces is included in the analysis. The experimental resul...

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

    Science.gov (United States)

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

    2008-10-01

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

  16. Development of novel and sensitive sensors based on microcantilever of atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    JIN Yan; WANG Kemin; JIN Rong

    2006-01-01

    Recently, the development of sensors based on microfabricated cantilevers of atomic force microscope (AFM) has attracted considerable attention from the designers of novel physical, chemical, and biological sensors. Many kinds of sensors have been developed taking the advantages of its high-resolution imaging, force measurement and force sensitivity, such as immunosensor and DNA biosensor and the sensors for detection of intermolecular interaction. This paper reviews the progress made in this field and discusses the signal transfer principles by which the design of the sensors is achieved.

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

    Science.gov (United States)

    Helas, G.; Andreae, M. O.

    2008-10-01

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

  18. The NanoBeamBalance: A passive, tensile-test device for the atomic force microscope

    Science.gov (United States)

    Wenger, M. P. E.; Mesquida, P.

    2011-05-01

    An add-on device is presented, which significantly expands the force measurement capabilities of the atomic force microscope (AFM). The device consists of a completely passive mechanism, which translates the vertical motion of the AFM tip in force measurements into a horizontal motion of two sample support pads. The advantage is that it is much easier to deposit microscopic samples from suspension onto flat surfaces than to attach them reliably between tip and a surface. The working-principle and the design of the device is comprehensively described and demonstrated on the example of collagen fibres with a diameter of a few μm. Well-defined tensile measurements in longitudinal direction were performed, showing that the tensile stiffness of collagen fibres from rat tail tendon decreases by a factor of 5 when rehydrated from a dried sample and slowly increases upon cross-linking with glutaraldehyde.

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

    Science.gov (United States)

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

    2016-08-01

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

  20. Microscopical observations of Sphaerellopsis filum, a parasite of Puccinia recondita

    Directory of Open Access Journals (Sweden)

    Agnieszka Płachecka

    2012-12-01

    Full Text Available Sphaerellopsis filum is a well-known parasite associated with many species of rust fungi. It is of frequent occurrence as parasite of cereal rusts: Puccinia recondita, P. coronata, P. graminis, P. hordei and P. striiformis. Uredial sori of Puccinia recondita f.sp. tritici infected with Sphaerellopsis filum were examined by light and scanning microscope to determine morphology of hyperparasite as well as the parasite-hyperparasite contact. The microscopical examination of infected uredinia clearly showed the intimate connection of S. filum with its rust host.

  1. A study of the morphology of photochromic and thermochromic MoO 3 amorphous films using an atomic force microscope

    Science.gov (United States)

    Chudnovskii, F. A.; Schaefer, D. M.; Gavrilyuk, A. I.; Reifenberger, R.

    The surface morphology of amorphous MoO 3 films enhanced by a coating of N.N-dimethylformamide was studied with an atomic force microscope. Images of the as-grown films revealed a surface structure consisting of ˜25 nm diameter clusters which had coalesced to form irregular-shaped grains with dimensions ranging between 100 and 190 nm. Similar structure was found in the films after a photochromic or thermochromic transition had occured. The relative surface areas of the films have been calculated and little change is observed after the photochromic transition while a ˜29 increase in surface area is observed after the thermochromic transition has taken place.

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

    Science.gov (United States)

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

    2015-05-01

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

  3. Leakage radiation microscope for observation of non-transparent samples.

    Science.gov (United States)

    Merlo, Juan M; Ye, Fan; Burns, Michael J; Naughton, Michael J

    2014-09-22

    We describe a leakage radiation microscope technique that can be used to extend the leakage radiation microscopy to optically non-transparent samples. In particular, two experiments are presented, first to demonstrate that acquired images with our configuration correspond to the leakage radiation phenomenon and second, to show possible applications by directly imaging a plasmonic structure that previously could only be imaged with a near-field scanning optical microscope. It is shown that the measured surface plasmon wavelength and propagation length agree with theoretically-calculated values. This configuration opens the possibility to study important effects where samples are optically non-transparent, as in plasmonic cavities and single hole plasmonic excitation, without the use of time-consuming near-field scanning optical microscopy.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-08-15

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

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

    Science.gov (United States)

    Ji, Yanfeng; Hui, Fei; Shi, Yuanyuan; Iglesias, Vanessa; Lewis, David; Niu, Jiebin; Long, Shibing; Liu, Ming; Hofer, Alexander; Frammelsberger, Werner; Benstetter, Guenther; Scheuermann, Andrew; McIntyre, Paul C; Lanza, Mario

    2016-08-01

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

  6. Laser beam scanning microscope and piezoresponse force microscope studies on domain structured in 001-, 110-, and 111-oriented NaNbO3 films

    Science.gov (United States)

    Yamazoe, Seiji; Kohori, Akihiro; Sakurai, Hiroyuki; Kitanaka, Yuuki; Noguchi, Yuji; Miyayama, Masaru; Wada, Takahiro

    2012-09-01

    NaNbO3 (NN) films were epitaxially grown on SrRuO3/(001), (110), and (111)SrTiO3 substrates, and these NN films were characterized by a laser beam scanning microscope and a piezoresponse force microscope. The 001-oriented NN film had antiferroelectric 90° domains with 100 and 010 polarization axes and 90° domain walls exhibiting piezoresponse. The piezoresponding domain walls would be induced by ferroelasticity. On the other hand, the 110- and 111-oriented NN films possessed 60° domains. The 60° domains of 110-oriented NN film were constructed by antiferroelectric 11¯0 domain and piezoresponding {101} and {011} domains. In the case of 111-oriented NN, three kinds of 60° domains (11¯0 and 01¯1, 01¯1 and 101¯, and 101¯ and 11¯0) were observed. The fine domains with piezoresponse were also observed in the mixed region with the three 60° domains. From the stress measurement, we found that the difference in the domain structure of 001-, 110-, and 111-oriented NN films depends not only on the orientation direction but also on the stress from the substrate. Moreover, the stress and the induction of the piezoelectric domain also influence the dielectric behavior.

  7. Effect of hydration film on scanning images of atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A standard calibration grating was used for image scanning to investigate the effect of hydration films on imaging resolution by Atomic Force Microscope (AFM). The results showed that the hydration films greatly affect the imaging resolution for the tapping mode, but no evident effect on the contact mode. The possible reasons for the effect of hydration films on scanning images of AFM are also brought forward here.

  8. Estimation of the shear force in transverse dynamic force microscopy using a sliding mode observer

    Directory of Open Access Journals (Sweden)

    Thang Nguyen

    2015-09-01

    Full Text Available In this paper, the problem of estimating the shear force affecting the tip of the cantilever in a Transverse Dynamic Force Microscope (TDFM using a real-time implementable sliding mode observer is addressed. The behaviour of a vertically oriented oscillated cantilever, in close proximity to a specimen surface, facilitates the imaging of the specimen at nano-metre scale. Distance changes between the cantilever tip and the specimen can be inferred from the oscillation amplitudes, but also from the shear force acting at the tip. Thus, the problem of accurately estimating the shear force is of significance when specimen images and mechanical properties need to be obtained at submolecular precision. A low order dynamic model of the cantilever is derived using the method of lines, for the purpose of estimating the shear force. Based on this model, an estimator using sliding mode techniques is presented to reconstruct the unknown shear force, from only tip position measurements and knowledge of the excitation signal applied to the top of the cantilever. Comparisons to methods assuming a quasi-static harmonic balance are made.

  9. Probing molecular interaction between transferrin and anti-transferrin by atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The interaction between transferrin (Tf) and its antibody was investigated by atomic force microscope. Tf-antibody was immobilized on the Au-coated glass slide, and the specific combination between antibody and antigen was also characterized by AFM. The results showed that holo-transferrin was jogged with anti-transferrin, and binded anti-tran- sferrin more tightly than apo-transferrin. The force- distance curves revealed that the affinity of anti-trans- ferrin and holo-transferrin was much stronger than that of apo-transferrin.

  10. Apparatus for observing a sample with a particle beam and an optical microscope

    NARCIS (Netherlands)

    2010-01-01

    An apparatus for observing a sample (1) with a TEM column and an optical high resolution scanning microscope (10). The sample position when observing the sample with the TEM column differs from the sample position when observing the sample with the optical microscope in that in the latter case the

  11. Apparatus for observing a sample with a particle beam and an optical microscope

    NARCIS (Netherlands)

    2010-01-01

    An apparatus for observing a sample (1) with a TEM column and an optical high resolution scanning microscope (10). The sample position when observing the sample with the TEM column differs from the sample position when observing the sample with the optical microscope in that in the latter case the s

  12. Growth of InGaAs-capped InAs quantum dots characterized by Atomic Force Microscope and Scanning Electron Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Chen Shende; Tsai Chiouyun; Lee Sichen [National Taiwan University, Department of Electrical Engineering, Graduate Institute of Electronics Engineering (China)

    2004-08-15

    Atomic force microscopy (AFM) is typically used to measure the quantum dot shape and density formed by lattice mismatched epitaxial growth such as InAs on GaAs. However, AFM images are distorted when two dots are situated in juxtaposition with a distance less than the AFM tip width. Scanning electron Microscope (SEM) is much better in distinguishing the dot density but not the dot height. Through these measurements of the growth of In{sub x}Ga{sub 1-x}As cap layer on InAs quantum dots, it was observed that the InGaAs layer neither covered the InAs quantum dots and wetting layer uniformly nor 100% phase separates into InAs and GaAs grown on InAs quantum dots and wetting layer, respectively.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-15

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

  14. Observation of fluorscent particles in rain water using Laser scanning microscope

    OpenAIRE

    古池, 聖生; 鈴木, 款

    1997-01-01

    Rain water contains various insoluble particles. Detection and observation of in-soluble organic particles in rain water with a fluorescence microscope has been studied. A laser scanning microscope was used for observation of fluorescent particles. Rain water was collected from July 1996 to December 1996 in Shizuoka, and 17 rain water samples were collected. Fluorescent particles in rain water were characterized as organic matter using a Fourier transform infrared (FTIR) microscope. It was fo...

  15. Observation of dislocation dynamics in the electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Lagow, B W; Robertson, I M; Jouiad, M; Lassila, D H; Lee, T C; Birnbaum, H K

    2001-01-17

    Deformation experiments performed in-situ in the transmission electron microscope have led to an increased understanding of dislocation dynamics. To illustrate the capability of this technique two examples will be presented. In the first example, the processes of work hardening in Mo at room temperature will be presented. These studies have improved our understanding of dislocation mobility, dislocation generation, and dislocation-obstacle interactions. In the second example, the interaction of matrix dislocations with grain boundaries will be described. From such studies predictive criteria for slip transfer through grain boundaries have been developed.

  16. Observation of Dislocation Dynamics in the Electron Microscope

    Energy Technology Data Exchange (ETDEWEB)

    Lagow, B W; Robertson, I M; Jouiad, M; Lassila, D H; Lee, T C; Birnbaum, H K

    2001-08-21

    Deformation experiments performed in-situ in the transmission electron microscope have led to an increased understanding of dislocation dynamics. To illustrate the capability of this technique two examples will be presented. In the first example, the processes of work hardening in Mo at room temperature will be presented. These studies have improved our understanding of dislocation mobility, dislocation generation, and dislocation-obstacle interactions. In the second example, the interaction of matrix dislocations with grain boundaries will be described. From such studies predictive criteria for slip transfer through grain boundaries have been developed.

  17. The human chromosome. Electron microscopic observations on chromatin fiber organization.

    Science.gov (United States)

    Abuelo, J G; Moore, D E

    1969-04-01

    Human lymphocytes were grown in short-term tissue culture and were arrested in metaphase with Colcemid. Their chromosomes were prepared by the Langmuir trough-critical point drying technique and were examined under the electron microscope. In addition, some chromosomes were digested with trypsin, Pronase, or DNase. The chromosomes consist entirely of tightly packed, 240 +/- 50-A chromatin fibers. Trypsin and Pronase treatments induce relaxation of fiber packing and reveal certain underlying fiber arrangements. Furthermore, trypsin treatment demonstrates that the chromatin fiber has a 25-50 A trypsin-resistant core surrounded by a trypsin-sensitive sheath. DNase digestion suggests that this core contains DNA.

  18. Dual-cut graphene transistors with constant-current regions fabricated by the atomic force microscope anode oxidation

    Science.gov (United States)

    Wu, Chong-Rong; Dou, Kun Peng; Wang, Cheng-Hung; Chang, Chung-En; Kaun, Chao-Cheng; Wu, Chao-Hsin; Lin, Shih-Yen

    2017-01-01

    Graphene bandgap opening is an important issue for the application of this material. We have demonstrated that by atomic force microscope (AFM) anode oxidation, long nonconductive oxidation lines can be fabricated on graphene surfaces. By using this fabrication technique with the dual-cut transistor architecture, the phenomenon of constant-current regions near the Dirac point can be observed in devices at room temperature when the cut separation is smaller than 100 nm. The results may provide evidence of the phenomenon of graphene bandgap opening at room temperature. The theoretical bandgap values are further estimated by density-function-derived tight-binding calculations.

  19. A virtual instrument to standardise the calibration of atomic force microscope cantilevers

    CERN Document Server

    Sader, John E; Gibson, Christopher T; Haviland, David B; Higgins, Michael J; Kilpatrick, Jason I; Lu, Jianing; Mulvaney, Paul; Shearer, Cameron J; Slattery, Ashley D; Thorén, Per-Anders; Tran, Jim; Zhang, Heyou; Zhang, Hongrui; Zheng, Tian

    2016-01-01

    Atomic force microscope (AFM) users often calibrate the spring constants of cantilevers using functionality built into individual instruments. This is performed without reference to a global standard, which hinders robust comparison of force measurements reported by different laboratories. In this article, we describe a virtual instrument (an internet-based initiative) whereby users from all laboratories can instantly and quantitatively compare their calibration measurements to those of others - standardising AFM force measurements - and simultaneously enabling non-invasive calibration of AFM cantilevers of any geometry. This global calibration initiative requires no additional instrumentation or data processing on the part of the user. It utilises a single website where users upload currently available data. A proof-of-principle demonstration of this initiative is presented using measured data from five independent laboratories across three countries, which also allows for an assessment of current calibratio...

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

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2008-10-01

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

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

    Directory of Open Access Journals (Sweden)

    G. Helas

    2008-08-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-02-01

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

  3. Cellular level nanomanipulation using atomic force microscope aided with superresolution imaging

    Science.gov (United States)

    Chacko, Jenu Varghese; Harke, Benjamin; Canale, Claudio; Diaspro, Alberto

    2014-10-01

    Atomic force microscopes (AFM) provide topographical and mechanical information of the sample with very good axial resolution, but are limited in terms of chemical specificity and operation time-scale. An optical microscope coupled to an AFM can recognize and target an area of interest using specific identification markers like fluorescence tags. A high resolution fluorescence microscope can visualize fluorescence structures or molecules below the classical optical diffraction limit and reach nanometer scale resolution. A stimulated emission depletion (STED) microscopy superresolution (SR) microscope coupled to an AFM is an example in which the AFM tip gains nanoscale manipulation capabilities. The SR targeting and visualization ability help in fast and specific identification of subdiffraction-sized cellular structures and manoeuvring the AFM tip onto the target. We demonstrate how to build a STED AFM and use it for biological nanomanipulation aided with fast visualization. The STED AFM based bionanomanipulation is presented for the first time in this article. This study points to future nanosurgeries performable at single-cell level and a physical targeted manipulation of cellular features as it is currently used in research domains like nanomedicine and nanorobotics.

  4. The relation between a microscopic threshold-force model and macroscopic models of adhesion

    Science.gov (United States)

    Hulikal, Srivatsan; Bhattacharya, Kaushik; Lapusta, Nadia

    2017-01-01

    This paper continues our recent work on the relationship between discrete contact interactions at the microscopic scale and continuum contact interactions at the macroscopic scale (Hulikal et al., J. Mech. Phys. Solids 76, 144-161, 2015). The focus of this work is on adhesion. We show that a collection of a large number of discrete elements governed by a threshold-force based model at the microscopic scale collectively gives rise to continuum fracture mechanics at the macroscopic scale. A key step is the introduction of an efficient numerical method that enables the computation of a large number of discrete contacts. Finally, while this work focuses on scaling laws, the methodology introduced in this paper can also be used to study rough-surface adhesion.

  5. Improved social force model based on exit selection for microscopic pedestrian simulation in subway station

    Institute of Scientific and Technical Information of China (English)

    郑勋; 李海鹰; 孟令云; 许心越; 陈旭

    2015-01-01

    An improved social force model based on exit selection is proposed to simulate pedestrians’ microscopic behaviors in subway station. The modification lies in considering three factors of spatial distance, occupant density and exit width. In addition, the problem of pedestrians selecting exit frequently is solved as follows: not changing to other exits in the affected area of one exit, using the probability of remaining preceding exit and invoking function of exit selection after several simulation steps. Pedestrians in subway station have some special characteristics, such as explicit destinations, different familiarities with subway station. Finally, Beijing Zoo Subway Station is taken as an example and the feasibility of the model results is verified through the comparison of the actual data and simulation data. The simulation results show that the improved model can depict the microscopic behaviors of pedestrians in subway station.

  6. A versatile atomic force microscope for three-dimensional nanomanipulation and nanoassembly

    Energy Technology Data Exchange (ETDEWEB)

    Xie Hui; Haliyo, Dogan Sinan; Regnier, Stephane [Institut des Systemes Intelligents et de Robotique, Universite Pierre et Marie Curie/CNRS UMR7222, BC 173, 4 Place Jussieu, F-75005 Paris (France)], E-mail: xie@robot.jussieu.fr

    2009-05-27

    A conventional atomic force microscope (AFM) has been successfully applied to manipulating nanoparticles (zero-dimensional), nanowires (one-dimensional) or nanotubes (one- or two-dimensional) by widely used pushing or pulling operations on a single surface. However, pick-and-place nanomanipulation in air is still a challenge. In this research, a modified AFM, called a three-dimensional (3D) manipulation force microscope (3DMFM), was developed to realize 3D nanomanipulation in air. This system consists of two individually actuated cantilevers with protruding tips that are facing each other, constructing a nanotweezer for the pick-and-place nanomanipulation. Before manipulation, one of the cantilevers is employed to position nano-objects and locate the tip of the other cantilever by image scanning. During the manipulation, these two cantilevers work collaboratively as a nanotweezer to grasp, transport and place the nano-objects with real-time force sensing. The manipulation capabilities of the nanotweezer were demonstrated by grabbing and manipulating silicon nanowires to build 3D nanowire crosses. 3D nanomanipulation and nanoassembly performed in air could become feasible through this newly developed 3DMFM.

  7. Light microscope observations on the epididymis of paca (Agouti paca).

    Science.gov (United States)

    Schimming, Bruno Cesar; Machado, Márcia Rita Fernandes; Simões, Karina; da Cruz, Claudinei; Domeniconi, Raquel Fantin

    2013-01-01

    The features of paca epididymis, based on its appearance in light microscope, is described in this paper. The cellular population of the epithelial lining comprises principal cells, basal cells, apical cells, narrows cells, and hallo cells. The epididymis is divided in five distinct and continuous regions, Zone I, or initial segment, and zone II, are both localized into the head. Zone III comprises the distal head and all the body. Zones IV and V are restricted to the tail, in the proximal and distal cauda epididymis respectively. Each zone can be readily distinguished on the basis of morphological characteristics. The height of epididymal epithelium is greater in zone I. There is a progressive increase in the diameter of the tubular lumen through the different areas, with the maximum in the zone V. The presence of a high epithelium, and the virtual absence of sperm in zone I suggest fast transit of spermatozoa in this region. Zone V comprises the distal tail, has smaller epithelial lining, greater luminal diameter, shorter stereocilia than the other zones, and contains spermatozoa packed inside the lumen, that characterizes this zone as a place of sperm storage. The findings are compared with other reports in rodents and other domestic animals, to contribute to the understanding of epididymal morphophysiology.

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

    KAUST Repository

    Zhou, Zhoulong

    2012-04-01

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

  9. High resolution miniature dilatometer based on an atomic force microscope piezocantilever

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.-H.; Graf, D.; Murphy, T. P.; Tozer, S. W. [National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States); Schmiedeshoff, G. M. [Department of Physics, Occidental College, Los Angeles, California 90041 (United States)

    2009-11-15

    Thermal expansion, or dilation, is closely related to the specific heat, and provides useful information regarding material properties. The accurate measurement of dilation in confined spaces coupled with other limiting experimental environments such as low temperatures and rapidly changing high magnetic fields requires a new sensitive millimeter size dilatometer that has little or no temperature and field dependence. We have designed an ultracompact dilatometer using an atomic force microscope piezoresistive cantilever as the sensing element and demonstrated its versatility by studying the charge density waves in alpha uranium to high magnetic fields (up to 31 T). The performance of this piezoresistive dilatometer was comparable to that of a titanium capacitive dilatometer.

  10. Enhancing thermally induced effects on atomic force microscope cantilevers using optical microcavities

    Science.gov (United States)

    Duy Vy, Nguyen; Iida, Takuya

    2016-12-01

    A theory of enhancing thermally induced effects on atomic force microscope cantilevers with respect to the input power is proposed. An optical microcavity is used to increase the absorbed power and radiation pressure on thin films. We show that the response to the input power is enhanced up to an order of magnitude for cantilevers of ∼200 µm in length and ∼0.5 µm in thickness. A decrease in the absorbed power in the presence of cantilever deflection increases system endurability with respect to the input power. The study gives methods for amplifying and tuning vibration amplitudes in amplitude modulation modes with high sensitivity and low controlling input power.

  11. Aligning DNA on Si surface and cutting off by tips of atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    DNA is a kind of promising molecule as nano-lead to build or connect nano-devices due to its stable linear structure and certain conductivity. Many methods have been applied to constructing nano-patterns by using DNA molecule. In this report it is presented that (-DNA was aligned on Si substrate by using the free-flowing method and then imaged by an atomic force microscope (AFM). After the second liquid flow, a catenary-like pattern and a crossed network of -DNA were formed. In addition, the aligned (-DNA was successfully cut off by tips of AFM.

  12. Note: A novel atomic force microscope fast imaging approach: Variable-speed scanning

    Science.gov (United States)

    Zhang, Yudong; Fang, Yongchun; Yu, Jie; Dong, Xiaokun

    2011-05-01

    Imaging speed is one of the key factors limiting atomic force microscope's (AFM) wide applications. To improve its performance, a variable-speed scanning (VSS) method is designed in this note for an AFM. Specifically, in the VSS mode, the scanning speed is tuned online according to the feedback information to properly distribute imaging time along sample surface. Furthermore, some practical mechanism is proposed to determine the best time of moving the AFM tip to the next scanned point. The contrast experiment results show that the VSS method speeds up the imaging rate while ensuring image quality.

  13. 3D mechanical measurements with an atomic force microscope on 1D structures

    DEFF Research Database (Denmark)

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

    2012-01-01

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

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

    CERN Document Server

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

    1999-01-01

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

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

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  16. Single-molecule force spectroscopy studies of fibrin 'A-a' polymerization interactions via the atomic force microscope

    Science.gov (United States)

    Averett, Laurel E.

    Fibrin, the polymerized form of the soluble plasma protein fibrinogen, plays a critical role in hemostasis as the structural scaffold of blood clots. The primary functions of fibrin are to withstand the shear forces of blood flow and provide mechanical stability to the clot, protecting the wound. While studies have investigated the mechanical properties of fibrin constructs, the response to force of critical polymerization interactions such as the 'A--a' knob--hole interaction remains unclear. Herein, the response of the 'A--a' bond to force was examined at the single-molecule level using the atomic force microscope. Force spectroscopy methodology was developed to examine the 'A--a' interaction while reducing the incidence of both nonspecific and multiple molecule interactions. The rupture of this interaction resulted in a previously unreported characteristic force profile comprised of up to four events. We hypothesized that the first event represented reorientation of the fibrinogen molecule, the second and third represented unfolding of structures in the D region of fibrinogen, and the last event was the rupture of the 'A--a' bond weakened by prior structural unfolding. The configuration, molecular extension, and kinetic parameters of each event in the characteristic pattern were examined to compare the unfolding of fibrin to other proteins unfolded by force. Fitting the pattern with polymer models showed that the D region of fibrinogen could lengthen by ˜50% of the length of a fibrin monomer before rupture of the 'A--a' bond. Analysis showed that the second and third events had kinetic parameters similar to other protein structures unfolded by force. Studies of the dependence of the characteristic pattern on calcium, concentration of sodium chloride, pH, and temperature demonstrated that the incidence of the last event was affected by solution conditions. However, only low pH and high temperatures reduced the probability that an interaction was characteristic

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

    CERN Document Server

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-06-22

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

  19. Cellular replication and atomic force microscope imaging using a UV-Bioimprint technique.

    Science.gov (United States)

    Muys, J J; Alkaisi, M M; Evans, J J

    2006-09-01

    Replication and fixation techniques have been of considerable interest for imaging and analysis of biological cells since the introduction of electron and scanning probe microscopy. Although such tools as the atomic force microscope (AFM) permit in situ morphological studies at a magnitude of resolution beyond traditional optical microscopy, they are difficult to operate and their resolution capabilities are rarely realized. We used a UV-Bioimprint replication technique to imprint a polymer layer onto cells attached to a substrate and rapidly cure to create an impression of cell topography. Replicas of chemically fixed and untreated cells analyzed by atomic force microscopy demonstrate nanometer resolution in the transfer of replicated features. UV-Bioimprint presents an improvement over techniques using heat-curable polymers as well as an alternative technique to the direct imaging of cells. The motivation for UV-Bioimprint is to effectively integrate scanning probe microscopy tools for imaging of cellular ultrastructure.

  20. Atomic force microscope adhesion measurements and atomistic molecular dynamics simulations at different humidities

    Science.gov (United States)

    Seppä, Jeremias; Reischl, Bernhard; Sairanen, Hannu; Korpelainen, Virpi; Husu, Hannu; Heinonen, Martti; Raiteri, Paolo; Rohl, Andrew L.; Nordlund, Kai; Lassila, Antti

    2017-03-01

    Due to their operation principle atomic force microscopes (AFMs) are sensitive to all factors affecting the detected force between the probe and the sample. Relative humidity is an important and often neglected—both in experiments and simulations—factor in the interaction force between AFM probe and sample in air. This paper describes the humidity control system designed and built for the interferometrically traceable metrology AFM (IT-MAFM) at VTT MIKES. The humidity control is based on circulating the air of the AFM enclosure via dryer and humidifier paths with adjustable flow and mixing ratio of dry and humid air. The design humidity range of the system is 20-60 %rh. Force-distance adhesion studies at humidity levels between 25 %rh and 53 %rh are presented and compared to an atomistic molecular dynamics (MD) simulation. The uncertainty level of the thermal noise method implementation used for force constant calibration of the AFM cantilevers is 10 %, being the dominant component of the interaction force measurement uncertainty. Comparing the simulation and the experiment, the primary uncertainties are related to the nominally 7 nm radius and shape of measurement probe apex, possible wear and contamination, and the atomistic simulation technique details. The interaction forces are of the same order of magnitude in simulation and measurement (5 nN). An elongation of a few nanometres of the water meniscus between probe tip and sample, before its rupture, is seen in simulation upon retraction of the tip in higher humidity. This behaviour is also supported by the presented experimental measurement data but the data is insufficient to conclusively verify the quantitative meniscus elongation.

  1. Measurements of dispersion forces between colloidal latex particles with the atomic force microscope and comparison with Lifshitz theory.

    Science.gov (United States)

    Elzbieciak-Wodka, Magdalena; Popescu, Mihail N; Montes Ruiz-Cabello, F Javier; Trefalt, Gregor; Maroni, Plinio; Borkovec, Michal

    2014-03-14

    Interaction forces between carboxylate colloidal latex particles of about 2 μm in diameter immersed in aqueous solutions of monovalent salts were measured with the colloidal probe technique, which is based on the atomic force microscope. We have systematically varied the ionic strength, the type of salt, and also the surface charge densities of the particles through changes in the solution pH. Based on these measurements, we have accurately measured the dispersion forces acting between the particles and estimated the apparent Hamaker constant to be (2.0 ± 0.5) × 10(-21) J at a separation distance of about 10 nm. This value is basically independent of the salt concentration and the type of salt. Good agreement with Lifshitz theory is found when roughness effects are taken into account. The combination of retardation and roughness effects reduces the value of the apparent Hamaker constant and its ionic strength dependence with respect to the case of ideally smooth surfaces.

  2. Measurements of dispersion forces between colloidal latex particles with the atomic force microscope and comparison with Lifshitz theory

    Energy Technology Data Exchange (ETDEWEB)

    Elzbieciak-Wodka, Magdalena; Ruiz-Cabello, F. Javier Montes; Trefalt, Gregor; Maroni, Plinio; Borkovec, Michal, E-mail: michal.borkovec@unige.ch [Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, 30, Quai Ernest-Ansermet, 1205 Geneva (Switzerland); Popescu, Mihail N. [Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095 (Australia)

    2014-03-14

    Interaction forces between carboxylate colloidal latex particles of about 2 μm in diameter immersed in aqueous solutions of monovalent salts were measured with the colloidal probe technique, which is based on the atomic force microscope. We have systematically varied the ionic strength, the type of salt, and also the surface charge densities of the particles through changes in the solution pH. Based on these measurements, we have accurately measured the dispersion forces acting between the particles and estimated the apparent Hamaker constant to be (2.0 ± 0.5) × 10{sup −21} J at a separation distance of about 10 nm. This value is basically independent of the salt concentration and the type of salt. Good agreement with Lifshitz theory is found when roughness effects are taken into account. The combination of retardation and roughness effects reduces the value of the apparent Hamaker constant and its ionic strength dependence with respect to the case of ideally smooth surfaces.

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

    Science.gov (United States)

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

    2008-10-01

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

  4. Combined low-temperature scanning tunneling/atomic force microscope for atomic resolution imaging and site-specific force spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Udo; Albers, Boris J.; Liebmann, Marcus; Schwendemann, Todd C.; Baykara, Mehmet Z.; Heyde, Markus; Salmeron, Miquel; Altman, Eric I.; Schwarz, Udo D.

    2008-02-27

    The authors present the design and first results of a low-temperature, ultrahigh vacuum scanning probe microscope enabling atomic resolution imaging in both scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NC-AFM) modes. A tuning-fork-based sensor provides flexibility in selecting probe tip materials, which can be either metallic or nonmetallic. When choosing a conducting tip and sample, simultaneous STM/NC-AFM data acquisition is possible. Noticeable characteristics that distinguish this setup from similar systems providing simultaneous STM/NC-AFM capabilities are its combination of relative compactness (on-top bath cryostat needs no pit), in situ exchange of tip and sample at low temperatures, short turnaround times, modest helium consumption, and unrestricted access from dedicated flanges. The latter permits not only the optical surveillance of the tip during approach but also the direct deposition of molecules or atoms on either tip or sample while they remain cold. Atomic corrugations as low as 1 pm could successfully be resolved. In addition, lateral drifts rates of below 15 pm/h allow long-term data acquisition series and the recording of site-specific spectroscopy maps. Results obtained on Cu(111) and graphite illustrate the microscope's performance.

  5. Combined low-temperature scanning tunneling/atomic force microscope for atomic resolution imaging and site-specific force spectroscopy

    Science.gov (United States)

    Albers, Boris J.; Liebmann, Marcus; Schwendemann, Todd C.; Baykara, Mehmet Z.; Heyde, Markus; Salmeron, Miquel; Altman, Eric I.; Schwarz, Udo D.

    2008-03-01

    We present the design and first results of a low-temperature, ultrahigh vacuum scanning probe microscope enabling atomic resolution imaging in both scanning tunneling microscopy (STM) and noncontact atomic force microscopy (NC-AFM) modes. A tuning-fork-based sensor provides flexibility in selecting probe tip materials, which can be either metallic or nonmetallic. When choosing a conducting tip and sample, simultaneous STM/NC-AFM data acquisition is possible. Noticeable characteristics that distinguish this setup from similar systems providing simultaneous STM/NC-AFM capabilities are its combination of relative compactness (on-top bath cryostat needs no pit), in situ exchange of tip and sample at low temperatures, short turnaround times, modest helium consumption, and unrestricted access from dedicated flanges. The latter permits not only the optical surveillance of the tip during approach but also the direct deposition of molecules or atoms on either tip or sample while they remain cold. Atomic corrugations as low as 1pm could successfully be resolved. In addition, lateral drifts rates of below 15pm/h allow long-term data acquisition series and the recording of site-specific spectroscopy maps. Results obtained on Cu(111) and graphite illustrate the microscope's performance.

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

    Science.gov (United States)

    Zhong, Jian; He, Dannong

    2015-08-01

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

  7. The study of nanoscratch and nanomachining on hard multilayer thin films using atomic force microscope.

    Science.gov (United States)

    Huang, Jen-Ching; Li, Chia-Lin; Lee, Jyh-Wei

    2012-01-01

    In this study, nanoscratching and nanomachining were conducted using an atomic force microscope (AFM) equipped with a doped diamond-coated probe (DDESP-10; VEECO) to evaluate the fabrication of nanopatterns on hard, Cr₂N/Cu multilayer thin films. The influence of normal force, scratch speed, and repeated scratches on the properties of hard multilayer thin films was also investigated. The nanoscratch experiments led researchers to establish a probe preparation and selection criteria (PPS criteria) to enhance the stability and accuracy of machining hard materials. Experimental results indicate that the depth of grooves produced by nanoscratching increased with an increase in normal force, while an increase in the number of scratches in a single location increased the groove depth but decreased friction. Therelationships among normal force and groove depth more closely resembled a logarithmic form than other mathematical models, as did the relationship between repeated scratching and its effect on groove depth and friction. The influence of scratch speed on friction was divided into two ranges. Between 0.1 and 2 µm/s, friction decreased logarithmically with an increase in scratch speed; however, when the speed exceeded 2 µm/s, the friction appeared stable. In this study, multilayered coatings were successfully machined, demonstrating considerable promise for the fabrication of nanopatterns in multilayered coatings at the nanoscale.

  8. Manufacture and scanning electron microscopic observation of human dermis collagen membrane

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    @@ Introduction Collagen is a kind of biomacromolecule and can be used as cover material for burn wounds. In this article,we report the scanning electron microscopic observation of human dermis collagen membrane prepared by three methods.

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

    Energy Technology Data Exchange (ETDEWEB)

    Liao, H.-S.; Chen, Y.-H.; Hwu, E.-T.; Chang, C.-S.; Hwang, I.-S., E-mail: ishwang@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Ding, R.-F.; Huang, H.-F.; Wang, W.-M. [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan (China); Huang, K.-Y. [Department of Mechanical Engineering, National Taiwan University, Taipei 10617, Taiwan (China)

    2014-10-15

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

  10. Imaging and analyzing the elasticity of vascular smooth muscle cells by atomic force acoustic microscope.

    Science.gov (United States)

    Zhang, Bo; Cheng, Qian; Chen, Ming; Yao, Wengang; Qian, Menglu; Hu, Bing

    2012-08-01

    Vascular smooth muscle cells (VSMCs) play an important role in the good performance of the vasculature. To study the surface, intracellular structure and elasticity of VSMCs, atomic force acoustic microscope (AFAM) was used for imaging VSMCs from A7r5 rat aorta arteries. The topography images of VSMCs were obtained in contact mode and the acoustic images were obtained by AFAM in sample vibration mode. Then, the force curve measurement derived using Young's modulus of the interested areas was used for evaluating elasticity properties. The acoustic images were found in higher resolution with more information than the topography images. The force curves showed the difference in Young's modulus of the different parts of VSMC. These findings demonstrate that AFAM is useful for displaying the surface, structure and elasticity property of VSMCs clearly, with short scanning time, negligible harm or damage to cell and nanometer-level resolution. Copyright © 2012 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  11. Position-resolved Surface Characterization and Nanofabrication Using an Optical Microscop e Combined with a Nanopip ette/Quartz Tuning Fork Atomic Force Microscop e

    Institute of Scientific and Technical Information of China (English)

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

    2014-01-01

    In this work, we introduce position-resolved surface characterization and nanofabrication us-ing an optical microscope (OM) combined with a nanopipette-based quartz tuning fork atomic force micro-scope (nanopipette/QTF-AFM) system. This system is used to accurately determine substrate position and nanoscale phenomena under ambient conditions. Solutions consisting of 5 nm Au nanoparticles, nanowires, and polydimethylsiloxane (PDMS) are deposited onto the substrate through the nano/microaperture of a pulled pipette. Nano/microscale patterning is performed using a nanopipette/QTF-AFM, while position is resolved by monitoring the substrate with a custom OM. With this tool, one can perform surface characterization (force spectroscopy/microscopy) using the quartz tuning fork (QTF) sensor. Nanofabrication is achieved by accu-rately positioning target materials on the surface, and on-demand delivery and patterning of various solutions for molecular architecture.

  12. Crack Coalescence in Molded Gypsum and Carrara Marble: Part 2—Microscopic Observations and Interpretation

    Science.gov (United States)

    Wong, L. N. Y.; Einstein, H. H.

    2009-06-01

    Experimental uniaxial compression loading tests were conducted on molded gypsum and Carrara marble prismatic specimens to study the cracking and coalescence processes between pre-existing artificial flaws. The study showed that material had an influence on the cracking and coalescence processes (see the companion paper in this issue). As reported in the companion paper, one of the pronounced features as observed in the high-speed video recordings was the development of macroscopic white patches prior to the development of observable cracks in marble, but not in gypsum. This paper (part 2) deals with the microscopic aspects of the study. Specifically, the scanning electron microscope (SEM) and the environmental scanning electron microscope (ESEM) imaging techniques were used to study the microscopic development of white patches and their evolution into macroscopic tensile cracks and shear cracks in marble, and the microscopic initiation of hair-line tensile cracks and their evolution into macroscopic tensile cracks in gypsum. The microscopic imaging study in marble showed that the white patches were associated with extensive microcracking zones (process zones), while the extent of process zone development in gypsum was limited. The comparison of the macroscopic and microscopic results indicates that the different extent of microcracking zone development, related to the material textural properties, is a key factor leading to different macroscopic cracking behavior in gypsum and marble.

  13. Development of a Hybrid Atomic Force Microscopic Measurement System Combined with White Light Scanning Interferometry

    Directory of Open Access Journals (Sweden)

    Xiaotang Hu

    2011-12-01

    Full Text Available A hybrid atomic force microscopic (AFM measurement system combined with white light scanning interferometry for micro/nanometer dimensional measurement is developed. The system is based on a high precision large-range positioning platform with nanometer accuracy on which a white light scanning interferometric module and an AFM head are built. A compact AFM head is developed using a self-sensing tuning fork probe. The head need no external optical sensors to detect the deflection of the cantilever, which saves room on the head, and it can be directly fixed under an optical microscopic interferometric system. To enhance the system’s dynamic response, the frequency modulation (FM mode is adopted for the AFM head. The measuring data can be traceable through three laser interferometers in the system. The lateral scanning range can reach 25 mm × 25 mm by using a large-range positioning platform. A hybrid method combining AFM and white light scanning interferometry is proposed to improve the AFM measurement efficiency. In this method, the sample is measured firstly by white light scanning interferometry to get an overall coarse morphology, and then, further measured with higher resolution by AFM. Several measuring experiments on standard samples demonstrate the system’s good measurement performance and feasibility of the hybrid measurement method.

  14. Nanotribological characterization of digital micromirror devices using an atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Liu Huiwen; Bhushan, Bharat

    2004-08-15

    Texas Instruments' digital micromirror device (DMD) comprises an array of fast digital micromirrors, monolithically integrated onto and controlled by an underlying silicon memory chip. The DMD is one of the few success stories in the emerging field of MEMS. In this study, an atomic force microscope (AFM) has been used to characterize the nanotribological properties of the elements of the DMD. An AFM methodology was developed to identify and remove micromirrors of interest. The surface roughness, adhesion, friction, and stiffness properties of the DMD elements were studied. The influence of relative humidity and temperature on the behavior of the DMD element surfaces was also investigated. Potential mechanisms for wear and stiction are discussed in light of the findings.

  15. Construction of a $^3$He magnetic force microscope with a vector magnet

    CERN Document Server

    Yang, Jinho; Kim, Yun Won; Shin, Dongwoo; Jeong, Juyoung; Wulferding, Dirk; Yeom, Han Woong; Kim, Jeehoon

    2016-01-01

    We constructed a $^3$He magnetic force microscope operating at the base temperature of 300 mK under a vector magnetic field of 2-2-9 T in the $x-y-z$ direction. Fiber optic interferometry as a detection scheme is employed in which two home-built fiber walkers are used for the alignment between the cantilever and the optical fiber. The noise level of the laser interferometer is close to its thermodynamic limit. The capabilities of the sub-Kelvin and vector field are demonstrated by imaging the coexistence of magnetism and superconductivity in a ferromagnetic superconductor (ErNi$_2$B$_2$C) at $T$=500 mK and by probing a dipole shape of a single Abrikosov vortex with an in-plane tip magnetization.

  16. Invited Review Nanoscale devices fabricated by dynamic ploughing with an atomic force microscope

    Science.gov (United States)

    Kunze, Ulrich

    2002-01-01

    A review is given on the dynamic ploughing technique and its application on the fabrication of nanoscale semiconductor structures. The vibrating tip of an atomic force microscope is used to dynamically plough furrows into a polymer layer of a few nm thickness on top of the semiconductor surface. Wet-chemical etching transfers the desired line pattern. The resulting grooves of 50-100 nm width form an arrangement of barriers in the electron layer of a conventional modulation-doped GaAs/AlGaAs heterostructure. A new type of heterostructure with a compensating p-type doped cap layer shows an electron enhancement if the cap layer is selectively removed. Etching a groove in these structures enables one to induce a one-dimensional electron system. Both types of structures are used to fabricate various ballistic quantum devices and Coulomb-blockade structures.

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

    DEFF Research Database (Denmark)

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

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning o...... areas traced in single scans of 40 mu m x 40 mu m. The results show that surface mapping on industrial surfaces is possible using the Least Mean Square alignment provided by the AFM software....... values in the order of 1 nm. The positioning repeatability of the two horizontal axes of the CMM was determined to +/-1 mu m. Sets of four 20 mu m x 20 mu m areas were traced on fiat objects, combining the data into single 40 mu m x 40 mu m areas, and comparing the roughness values to those for the same...

  18. Scanning thermal microscopy based on a modified atomic force microscope combined with pyroelectric detection

    Science.gov (United States)

    Antoniow, J.-S.; Chirtoc, M.; Trannoy, N.; Raphael, O.; Pelzl, J.

    2005-06-01

    We propose a novel approach in scanning thermal microscopy of layered samples. The thermal probe (ThP) (Wollaston wire) acts as a local a.c. heat source at the front of a sample layer deposited on a pyroelectric (PE) sensor. The PE signal is proportional to the heat wave transmitted through the sample. The ThP and PE signals can be used to generate complementary thermal conductivity maps and with some restrictions, thermal diffusivity maps of the sample. Additionally, the topography map is obtained in the usual way from the atomic force microscope. We give the theoretical background for the interpretation of PE signal obtained at low and at high frequency, and we demonstrate that it carries information on the thermal diffusivity of a test sample (12 μm thick PET polymer sheet). Finally, we discuss the contributions of heat transfer channels between ThP and sample, and the role of contact thermal resistance.

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

    CERN Document Server

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

    1998-01-01

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

  20. In situ measurements of human articular cartilage stiffness by means of a scanning force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Imer, Raphael [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland); Akiyama, Terunobu [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland); Rooij, Nico F de [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland); Stolz, Martin [Maurice E. Mueller Institute, University of Basel, Klingelbergstr. 70, 4056 Basel (Switzerland); Aebi, Ueli [Maurice E. Mueller Institute, University of Basel, Klingelbergstr. 70, 4056 Basel (Switzerland); Kilger, Robert [Clinics for Orthopedic Surgery and Traumatology, Kantonsspital, 4101 Bruderholz (Switzerland); Friederich, Niklaus F [Clinics for Orthopedic Surgery and Traumatology, Kantonsspital, 4101 Bruderholz (Switzerland); Wirz, Dieter [Lab. for Orthopaedic Biomechanics, University of Basel, Klingelbergstr. 50-70, 4056 Basel (Switzerland); Daniels, A U [Lab. for Orthopaedic Biomechanics, University of Basel, Klingelbergstr. 50-70, 4056 Basel (Switzerland); Staufer, Urs [Institute of Microtechnology, University of Neuchatel, Jaquet-Droz 1, 2007 Neuchatel (Switzerland)

    2007-03-15

    Osteoarthritis is a painful and disabling progressive joint disease, characterized by degradation of articular cartilage. In order to study this disease at early stages, we have miniaturized and integrated a complete scanning force microscope into a standard arthroscopic device fitting through a standard orthopedic canula. This instrument will allow orthopedic surgeons to measure the mechanical properties of articular cartilage at the nanometer and micrometer scale in-vivo during a standard arthroscopy. An orthopedic surgeon assessed the handling of the instrument. First measurements of the elasticity-modulus of human cartilage were recorded in a cadaver knee non minimal invasive. Second, minimally invasive experiments were performed using arthroscopic instruments. Load-displacement curves were successfully recorded.

  1. Toolkit for the Automated Characterization of Optical Trapping Forces on Microscopic Particles

    Science.gov (United States)

    Glaser, Joseph; Hoeprich, David; Resnick, Andrew

    2014-03-01

    Optical traps have been in use in microbiological studies for the past 40 years to obtain noninvasive control of microscopic particles. However, the magnitude of the applied forces is often unknown. Therefore, we have developed an automated data acquisition and processing system which characterizes trap properties for known particle geometries. Extensive experiments and measurements utilizing well-characterized objects were performed and compared to literature to confirm the system's performance. This system will enable the future analysis of a trapped primary cilium, a slender rod-shaped organelle with aspect ratio L/R >30, where `L' is the cilium length and `R' the cilium diameter. The trapping of cilia is of primary importance, as it will lead to the precise measurements of mechanical properties of the organelle and its significance to the epithelial cell. Support from the National Institutes of Health, 1R15DK092716 is gratefully acknowledged.

  2. Real time drift measurement for colloidal probe atomic force microscope: a visual sensing approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuliang, E-mail: wangyuliang@buaa.edu.cn; Bi, Shusheng [Robotics Institute, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Wang, Huimin [Department of Materials Science and Engineering, The Ohio State University, 2041 College Rd., Columbus, OH 43210 (United States)

    2014-05-15

    Drift has long been an issue in atomic force microscope (AFM) systems and limits their ability to make long time period measurements. In this study, a new method is proposed to directly measure and compensate for the drift between AFM cantilevers and sample surfaces in AFM systems. This was achieved by simultaneously measuring z positions for beads at the end of an AFM colloidal probe and on sample surface through an off-focus image processing based visual sensing method. The working principle and system configuration are presented. Experiments were conducted to validate the real time drift measurement and compensation. The implication of the proposed method for regular AFM measurements is discussed. We believe that this technique provides a practical and efficient approach for AFM experiments requiring long time period measurement.

  3. Design of mechanical components for vibration reduction in an atomic force microscope.

    Science.gov (United States)

    Kim, Chulsoo; Jung, Jongkyu; Youm, Woosub; Park, Kyihwan

    2011-03-01

    Vibration is a key factor to be considered when designing the mechanical components of a high precision and high speed atomic force microscope (AFM). It is required to design the mechanical components so that they have resonant frequencies higher than the external and internal vibration frequencies. In this work, the mechanical vibration in a conventional AFM system is analyzed by considering its mechanical components, and a vibration reduction is then achieved by reconfiguring the mechanical components. To analyze the mechanical vibration, a schematic of the lumped model of the AFM system is derived and the vibrational influences of the AFM components are experimentally examined. Based on this vibration analysis, a reconfigured AFM system is proposed and its effects are compared to a conventional system through a series of simulations and experiments.

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

    Directory of Open Access Journals (Sweden)

    Sakuma Y

    2006-01-01

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

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

    Science.gov (United States)

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

    2014-02-01

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

  6. Force Structure: Preliminary Observations on Air Force A-10 Divestment

    Science.gov (United States)

    2015-06-25

    disclosure . Therefore, this report omits certain information about military plans or operations, vulnerabilities or capabilities of systems or...Special Operations Command; Headquarters Air Force (A3, A5, A8, A9, and Financial Management); Air Combat Command (A3, A4, A5, and A8); Army (G-3/5/7 and...copyrighted images or other material , permission from the copyright holder may be necessary if you wish to reproduce this material separately. Page 9

  7. The influence of the Great East Japan earthquake on microscopic polyangiitis: A retrospective observational study.

    Science.gov (United States)

    Takeuchi, Yoichi; Saito, Ayako; Ojima, Yoshie; Kagaya, Saeko; Fukami, Hirotaka; Sato, Hiroyuki; Matsuda, Ken; Nagasawa, Tasuku

    2017-01-01

    Antineutrophil cytoplasmic antibody-associated vasculitis is triggered by environmental factors, including silica dust exposure. Repeated tsunami waves brought a large volume of silica-containing sludge inland after the Great East Japan earthquake in 2011. We aimed to determine if the serious disaster influenced the clinical features of the microscopic polyangiitis. This is an observational retrospective study conducted in a single institute. A total of 43 patients were included based on the CHCC2012 criteria for microscopic polyangiitis from 2007 to 2015. We used the Poisson regression model to determine the incidence of microscopic polyangiitis within the annual population of the medical district. The participants were selected during a 3-year period from before (N = 13) to after the disaster (N = 20). The differences of parameters and the overall survival between the groups were analyzed. The incidence of microscopic polyangiitis increased after the disaster (λ = 17.4/million/year [95%CI: 7.66-39.6] before the disaster and λ = 33.1/million/year [17.7-61.7] after the disaster, P = 0.044). A high Birmingham Activity Score was associated with a high incidence of microscopic polyangiitis after the disaster. The overall survival of the patients with microscopic polyangiitis declined significantly after the disaster. The Great East Japan earthquake influenced the development of the microscopic polyangiitis in our restricted area. The patients who developed after the disaster had severe symptoms and a high mortality rate.

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

    Science.gov (United States)

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

    2015-12-01

    The concept of "seeing by feeling" as a way to circumvent limitations on sight is universal on the macroscopic scale—reading Braille, feeling one's way around a dark room, etc. The development of the atomic force microscope (AFM) in 1986 extended this concept to imaging in the nanoscale. While there are classroom demonstrations that use a tactile probe to map the topography or some other property of a sample, the rastering of the probe over the sample is manually controlled, which is both tedious and potentially inaccurate. Other groups have used simulation or tele-operation of an AFM probe. In this paper we describe a teaching AFM with complete computer control to map out topographic and magnetic properties of a "crystal" consisting of two-dimensional arrays of spherical marble "atoms." Our AFM is well suited for lessons on the "Big Ideas of Nanoscale" such as tools and instrumentation, as well as a pre-teaching activity for groups with remote access AFM or mobile AFM. The principle of operation of our classroom AFM is the same as that of a real AFM, excepting the nature of the force between sample and probe.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-10-01

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

  10. An analytic model for accurate spring constant calibration of rectangular atomic force microscope cantilevers.

    Science.gov (United States)

    Li, Rui; Ye, Hongfei; Zhang, Weisheng; Ma, Guojun; Su, Yewang

    2015-10-29

    Spring constant calibration of the atomic force microscope (AFM) cantilever is of fundamental importance for quantifying the force between the AFM cantilever tip and the sample. The calibration within the framework of thin plate theory undoubtedly has a higher accuracy and broader scope than that within the well-established beam theory. However, thin plate theory-based accurate analytic determination of the constant has been perceived as an extremely difficult issue. In this paper, we implement the thin plate theory-based analytic modeling for the static behavior of rectangular AFM cantilevers, which reveals that the three-dimensional effect and Poisson effect play important roles in accurate determination of the spring constants. A quantitative scaling law is found that the normalized spring constant depends only on the Poisson's ratio, normalized dimension and normalized load coordinate. Both the literature and our refined finite element model validate the present results. The developed model is expected to serve as the benchmark for accurate calibration of rectangular AFM cantilevers.

  11. Microdrops on atomic force microscope cantilevers: evaporation of water and spring constant calibration.

    Science.gov (United States)

    Bonaccurso, Elmar; Butt, Hans-Jürgen

    2005-01-13

    The evaporation of water drops with radii approximately 20 microm was investigated experimentally by depositing them onto atomic force microscope (AFM) cantilevers and measuring the deflection versus time. Because of the surface tension of the liquid, the Laplace pressure inside the drop, and the change of interfacial stress at the solid-liquid interface, the cantilever is deflected by typically a few hundred nanometers. The experimental results are in accordance with an analytic theory developed. The evaporation process could be monitored with high accuracy even at the last stage of evaporation because (1) cantilever deflections can be measured with nanometer resolution and (2) the time resolution, given by the inverse of the resonance frequency of the cantilever of approximately 0.3 ms, is much faster than the typical evaporation time of 1 s. Experimental results indicate that evaporation of the last thin layer of water is significantly slower than the rest of the drop, which can be due to surface forces. This drop-on-cantilever system can also be used to analyze the drop impact dynamics on a surface and to determine the spring constant of cantilevers.

  12. Effects of microscopic transport coefficients on fission observables calculated by the Langevin equation

    Science.gov (United States)

    Usang, M. D.; Ivanyuk, F. A.; Ishizuka, C.; Chiba, S.

    2016-10-01

    Nuclear fission is treated by using the Langevin dynamical description with macroscopic and microscopic transport coefficients (mass and friction tensors), and it is elucidated how the microscopic (shell and pairing) effects in the transport coefficients, especially their dependence on temperature, affects various fission observables. We found that the microscopic transport coefficients, calculated by linear response theory, change drastically as a function of temperature: in general, the friction increases with growing temperature while the mass tensor decreases. This temperature dependence brings a noticeable change in the mass distribution and kinetic energies of fission fragments from nuclei around 236U at an excitation energy of 20 MeV. The prescission kinetic energy decreases from 25 MeV at low temperature to about 2.5 MeV at high temperature. In contrast, the Coulomb kinetic energy increases as the temperature increases. Interpolating the microscopic transport coefficients among the various temperatures enabled our Langevin equation to use the microscopic transport coefficients at a deformation-dependent local temperature of the dynamical evolution. This allowed us to compare directly the fission observables of both macroscopic and microscopic calculations, and we found almost identical results under the conditions considered in this work.

  13. Observation of MWCNTs with low-energy electron point source microscope

    Institute of Scientific and Technical Information of China (English)

    Yu Jie; Bai Xin; Zhang Zhao-Xiang; Zhang Geng-Min; Guo Deng-Zhu; Xue Zeng-Quan

    2006-01-01

    The low-energy electron point source (LEEPS) microscope, which creates enlarged projection images with lowenergy field emission electron beams, can be used to observe the projection image of nano-scale samples and to characterize the coherence of the field emission beam. In this paper we report the design and test operation performance of a home-made LEEPS microscope. Multi-walled carbon nanotubes (MWCNTs) synthesized by the CVD method were observed by LEEPS microscope using a conventional tungsten tip, and projection images with the magnification of up to 104 was obtained. The resolution of the acquired images is ~10 nm. A higher resolution and a larger magnification can be expected when the AC magnetic field inside the equipment is shielded and the vibration of the instrument reduced.

  14. A miniaturized, high frequency mechanical scanner for high speed atomic force microscope using suspension on dynamically determined points

    NARCIS (Netherlands)

    Herfst, R.W.; Dekker, A.; Witvoet, G.; Crowcombe, W.E.; Lange, T.J. de; Sadeghian Marnani, H.

    2015-01-01

    One of the major limitations in the speed of the atomic force microscope (AFM) is the bandwidth of the mechanical scanning stage, especially in the vertical (z) direction. According to the design principles of “light and stiff” and “static determinacy,” the bandwidth of the mechanical scanner is

  15. A miniaturized, high frequency mechanical scanner for high speed atomic force microscope using suspension on dynamically determined points

    NARCIS (Netherlands)

    Herfst, R.W.; Dekker, A.; Witvoet, G.; Crowcombe, W.E.; Lange, T.J. de; Sadeghian Marnani, H.

    2015-01-01

    One of the major limitations in the speed of the atomic force microscope (AFM) is the bandwidth of the mechanical scanning stage, especially in the vertical (z) direction. According to the design principles of “light and stiff” and “static determinacy,” the bandwidth of the mechanical scanner is lim

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

    Science.gov (United States)

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

    2000-04-01

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

  17. Atomic force microscopic study on topological structures of pBR322 DNA

    Institute of Scientific and Technical Information of China (English)

    张平城; 白春礼; 成英俊; 方晔; 王中怀; 黄熙泰

    1996-01-01

    Plasmid pBR322 DNA (0.5mg/mL) isolated from Escherichia coli HB101 was suspended in Tris-HCl-EDTA (1 mol/L - 0.1 mol/L, pH8.5); then a drop of the above solution was deposited on freshly cleaved mica substrate. After adsorption for about 1 min, the sample was stained with phosphotungstic acid. The residua] solution was removed with a piece of filter paper. Afterwards the sample was imaged with a home-made atomic force microscope (AFM) in air. The AFM images of pBR322 DNA with a molecular resolution have been obtained. These images show that pBR322 DNA exists in several different topological structures: (i) relaxed circular DNA with a different diameter; (ii) supercondensed DNA with different particle sizes; (iii) dimeric catenane connected by one relaxed circular molecule and another dose-compacted molecule which might be either supercoiled or intramolecular knotted form; (iv) oligomeric catenane with multiple irregular molecules in which DNA is interlocked into a complex oligomer; (v) possibly-existing

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

    Directory of Open Access Journals (Sweden)

    Higinio González-Jorge

    2010-04-01

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

  19. Fabrication and measurement of nanostructures on the micro ball surface using a modified atomic force microscope

    Science.gov (United States)

    Zhao, X. S.; Geng, Y. Q.; Li, W. B.; Yan, Y. D.; Hu, Z. J.; Sun, T.; Liang, Y. C.; Dong, S.

    2012-11-01

    In order to machine and measure nanostructures on the micro ball surface, a modified atomic force microscope (AFM) combining a commercial AFM system with a home built precision air bearing spindle is established. Based on this system, motions of both the AFM scanner and the air bearing spindle are controlled to machine nanostructures on the micro ball based on the AFM tip-based nano mechanical machining approach. The eccentric error between the axis of the micro ball and the axis of the spindle is reduced to 3-4 μm by the provided fine adjusting method. A 1000 nano lines array, 36 square pits structure, 10 square pits structure, and a zig-zag structure on the circumference of the micro ball with the diameter of 1.5 mm are machined successfully. The measurement results achieved by the same system reveal that the profiles and mode-power spectra curves of the micro ball are influenced by the artificially machined nanostructures significantly according to their distributions. This work is an useful attempt for modifying the micro ball profile and manufacture of the spherical modulation targets to study the experimental performance of the micro ball in implosion.

  20. The Asymmetrical Structure of Golgi Apparatus Membranes Revealed by In situ Atomic Force Microscope

    Science.gov (United States)

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

    2013-01-01

    The Golgi apparatus has attracted intense attentions due to its fascinating morphology and vital role as the pivot of cellular secretory pathway since its discovery. However, its complex structure at the molecular level remains elusive due to limited approaches. In this study, the structure of Golgi apparatus, including the Golgi stack, cisternal structure, relevant tubules and vesicles, were directly visualized by high-resolution atomic force microscope. We imaged both sides of Golgi apparatus membranes and revealed that the outer leaflet of Golgi membranes is relatively smooth while the inner membrane leaflet is rough and covered by dense proteins. With the treatment of methyl-β-cyclodextrin and Triton X-100, we confirmed the existence of lipid rafts in Golgi apparatus membrane, which are mostly in the size of 20 nm –200 nm and appear irregular in shape. Our results may be of significance to reveal the structure-function relationship of the Golgi complex and pave the way for visualizing the endomembrane system in mammalian cells at the molecular level. PMID:23613878

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-22

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Haijiao Xu

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

  5. Atomic Force Microscope Imaging of the Aggregation of Mouse Immunoglobulin G Molecules

    Directory of Open Access Journals (Sweden)

    Ke Xia

    2003-01-01

    Full Text Available Mouse immunoglobulin G (Ig G1 and the mixture of Ig G1 and Ig G2 deposited on mica were imaged with an atomic force microscope at room temperature and ambient pressure. At a concentration around 1.0mg/L, the molecules were well dispersed. 2~3 days after sample preparation, both Ig G1 and the mixture could self- assemble into different shapes and further form some types of local-ordered toroidal aggregations (monotoroidal, intercrossed toroidal, concentric toroidal, etc.. The number of monomers was not identical in the different toroidal aggregations but in a same circle, the shapes of polymer self-assembled by several monomolecules were found to be almost the same. There was difference between the aggregation behavior of Ig G1 and the mixture. The mechanism of Ig G molecule aggregation was ascribed to the “Y” shape and loops structure of Ig G molecule.

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

    Directory of Open Access Journals (Sweden)

    Seied Yasser Nikoo

    2016-11-01

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

  7. Observation of a Ag protrusion on a Ag2S island using a scanning tunneling microscope

    Directory of Open Access Journals (Sweden)

    Takeo Ohno

    2015-01-01

    Full Text Available A silver sulfide (Ag2S island as an ionic conductor in resistive switching memories was formed and a protrusion of silver from the Ag2S formed by an electrochemical reaction was observed using a scanning tunneling microscope.

  8. Quasi interference of perpendicularly polarized guided modes observed with a photon scanning tunneling microscope

    NARCIS (Netherlands)

    Balistreri, M.L.M.; Driessen, A.; Korterik, Jeroen P.; Kuipers, L.; van Hulst, N.F.

    2000-01-01

    The simultaneous detection of TE- as well as TM-polarized light with a photon scanning tunneling microscope leads to a quasi- interference pattern of these mutually perpendicular polarized fields. This interference pattern has been observed in the optical field distribution as a function of both pos

  9. Pancam and microscopic imager observations of dust on the Spirit Rovers

    DEFF Research Database (Denmark)

    Vaughan....[], Alicia F.; Johnson, Jeffrey R.; Walter, Goetz

    2010-01-01

    This work describes dust deposits on the Spirit Rover over 2000 sols through examination of Pancam and Microscopic Imager observations of specific locations on the rover body, including portions of the solar array, Pancam and Mini-TES calibration targets, and the magnets. This data set reveals th...

  10. Developmental morphology of the human fetus kidney : Observation by light and electron microscope

    OpenAIRE

    1998-01-01

    The author observed the human fetus kidney at the fetal age of 3 weeks, 5 weeks and 6 month in utero by means of light and electron microscope in order to add some new findings to the already known knowledge. Especially, the metanephros, metanephric blastema, nephrogenic zone of the cortex and blood-urine barrier which consists of glomerulus, capillary vessel, basement membrane, podocyte and mesangium cells are observed and then physiological significance of the kidney are also discussed. On ...

  11. Electron microscopic observations of terminals of functionally identified afferent fibers in cat spinal cord.

    Science.gov (United States)

    Egger, M D; Freeman, N C; Malamed, S; Masarachia, P; Proshansky, E

    1981-02-23

    Using the method of intra-axonal injection of horseradish peroxidase, functionally identified afferent fibers from three slowly adapting (Type I) receptors and one Pacinian corpuscle in the glabrous skin of the hind paw of the cat were stained. Electron microscopic observation of the terminals of these fibers revealed predominantly axodendritic asymmetric synapses containing round, clear vesicles. Multiple synapses on a single dendrite were observed, separated by as little as 900 mm from one another.

  12. Optical and atomic force microscopic study on step bunching in BaB2O4 crystal growth

    Institute of Scientific and Technical Information of China (English)

    Pan Xiu-Hong; Jin Wei-Qing; Liu Yan; Ai Fei; Jin Fei; Xie Jun-Jie

    2011-01-01

    The formation of macrostep during high-temperature phase of barium meta-borate (α-BaB2O4) single crystal growth has been investigated by both optical in-situ observation system and atomic force microscopy (AFM). The in-situ observation results demonstrate that the critical linear size of growing facet exceeding the size that the macrostep generates is significantly anisotropic. The critical linear sizes are around 280 μm and 620 μm for {10(1)0} and {(1)010} planes, respectively. AFM study illustrates that macrostep train with a height of 150 nm~200 nm is one typical morphological feature of the as-grown crystal surface. The riser of each macrostep consists of several straight and parallel sub-steps, indicating the occurrence of step bunching. Additionally, triangular sub-steps with heights of several nanometers on the treads of the macrosteps are found to be another typical feature of surface morphology, which implies a microscopically competitive bunching of sub-steps between various crystallographic orientations.

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

    Science.gov (United States)

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

    2011-12-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

  15. Scanning Electron Microscopic Observation on Morphologic Characteristics of Sperms in Uremic Patients

    Institute of Scientific and Technical Information of China (English)

    Long-gen XU; Shi-fang SHI; Hai-zhen ZHONG; Xiao-feng HUANG; Xiao-ping QI; Qi-zhe SONG; Xin-hong WANG; Li YAN; Zong-fu SHAO

    2004-01-01

    Objective To observe the morphologic characteristics of spermatozoon ultramicro scopic structure in uremic subjects Method Semen sample from 10 patients with uremia and 5 healthy men were observed under light microscope and scanning electronic microscope.Results Abnormalities were found in sperms of uremic patients either in the sperm head (acrosome, acrosomic deficit, nuclear abnormality, pointed head, headless and double head of spermatozoon), neck (rupture, separation and enlargement), or tail (mitochondrial swelling, mitochondrial deficit, tailless, double tail, short tail and curled tail); whereas none of the above-mentioned abnormalities was observed in healthy men.Conclusion Sperms of uremic patients had many morphologic and structural abnor malities in the head, neck and tail.

  16. Light-microscopic observations of individual microtubules reconstituted from brain tubulin.

    Science.gov (United States)

    Kuriyama, R; Miki-Noumura, T

    1975-12-01

    The course of polymerization of individual brain microtubules could be observed with a light microscope employing dark-field illumination. Statistical analysis of the increase in microtubule length during the polymerization was in accordance with the time course of viscosity change of the tubulin solution. After a plateau level in viscosity was attained, there was no significant change in histograms showing length distribution. These observations were confirmed with fixed and stained microtubules, using a phase-contrast microscope. Observations with dark-field illumination revealed that reconstituted microtubules depolymerized and disappeared immediately upon exposure to buffer containing CaCl2 or sulphydryl reagents such as p-chloromercuriphenyl sulphonic acid (PCMPS) and p-chloromercuribenzoic acid (PCMB). They were also cold-labile. The growth of heterogeneous microtubules which were assembled by mixing purified tubulin dimers with ciliary outer fibres could also be followed with these optical systems.

  17. Stability behavior of non-surfactant water-in-diesel emulsion fuel using microscopic observation

    Directory of Open Access Journals (Sweden)

    Norazni Siti Amiliyana

    2017-01-01

    Full Text Available Water-in-diesel emulsion fuel (W/D is considered to be a potential alternative fuel that can reduces nitrogen oxides (NOx and particulate matter (PM. W/D is normally produced with addition of surfactant to prolong its stability. However, the dependency on surfactant leads to higher production cost. A concept that can eliminate dependency on the surfactant was introduced by strong mixing concept and direct supply the non-surfactant W/D to a diesel engine. Therefore, the objective of this study is to investigate the stability behavior of non-surfactant W/D using microscopic observation. Water and diesel fuel were mixed using a combination of high-shear mixer and an ultrasonic transducer. The amount of water injected into the system are 5% and 10% by volume, which were labelled as E5 and E10 respectively. The produced non-surfactant W/D was then placed into a petri dish for microscopic observation. The results showed that the average diameter of water droplets observed in E5 and E10 at sedimentation stage were 15.38 and 22.41 μm respectively. The stability period of E5 and E10 before it sediment were 25 and 67 seconds correspondingly. Overall, it is observed that microscopic observation is a reliable approach to determine the stability behavior of non-surfactant W/D.

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

    Science.gov (United States)

    Nahavandi, Amir; Korayem, Moharam Habibnejad

    2015-10-01

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

  19. Spatial resolution and switching field of magnetic force microscope tip coated with FePd-alloy thin film

    Directory of Open Access Journals (Sweden)

    Futamoto Masaaki

    2013-01-01

    Full Text Available Magnetic force microscope (MFM tips are prepared by coating Si tips of 4 nm radius with L10 ordered FePd-alloy films varying the thickness in a range between 10 and 80 nm. The effects of coating thickness on spatial resolution and switching field of MFM tip are investigated. As the thickness increases from 10 to 20 nm, the MFM signal detection sensitivity is improved and the resolution improves from 12.7 to 7.9 nm. With further increasing the thickness, the resolution decreases due to increase of tip radius. Magnetic bits of 15.9 nm length of a perpendicular medium recorded at 1600 kilo-flux-change-per-inch are distinguishable in the MFM image observed by using a tip coated with 20-nm-thick FePd film. The switching field monotonically increases from 0.70 to 1.50 kOe with increasing the coating thickness from 10 to 80 nm. The present study has shown that it is possible to prepare an MFM tip with spatial resolution better than 10 nm and switching field higher than 1 kOe by coating a sharp Si tip with an L10 ordered FePd-alloy film.

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

    Science.gov (United States)

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

    2013-08-01

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

  1. Observation of sperm-head vacuoles and sperm morphology under light microscope.

    Science.gov (United States)

    Park, Yong-Seog; Park, Sol; Ko, Duck Sung; Park, Dong Wook; Seo, Ju Tae; Yang, Kwang Moon

    2014-09-01

    The presence of sperm-head vacuoles has been suspected to be deleterious to the outcomes of assisted reproductive technology (ART). It is difficult to accurately distinguish morphologically abnormal sperm with vacuoles under a light microscope. This study was performed to analyze the result of the observation of sperm-head vacuoles using Papanicolaou staining under a light microscope and whether the male partner's age affects these vacuoles. Sperm morphology with vacuoles was evaluated using Papanicolaou staining and observed under a light microscope (400×) in 980 men. The normal morphology was divided into three categories (group A, 14% of normal morphology). The criteria for the sperm-head vacuoles were those given in the World Health Organization manual. For the analysis of the age factor, the participants were divided into the following groups: 26-30 years, 31-35 years, 36-40 years, 41-45 years, and 46-50 years. The percentage of sperm-head vacuoles increased with normal sperm morphology (group A vs. groups B, C) (p<0.05). In the case of the age factor, a statistically significant difference was not observed across any of the age groups. A majority of the sperm-head vacuoles showed a statistically significant difference among normal morphology groups. Therefore, we should consider the probability of the percentage of sperm-head vacuoles not increasing with age but with abnormal sperm morphology. A further study is required to clarify the effect of the sperm-head vacuoles on ART outcomes.

  2. Phenotypic and genotypic characterization of biofilm formation among Staphylococcus aureus isolates from clinical specimens, an Atomic Force Microscopic (AFM) study.

    Science.gov (United States)

    Bazari, Pelin Aslani Menareh; Honarmand Jahromy, Sahar; Zare Karizi, Shohreh

    2017-09-01

    Staphylococcus aureus is a major cause of nosocomial infections. Biofilm formation is an important factor for bacterial pathogenesis. Its mechanisms are complex and include of many genes depends on expression of icaADBC operon involved in the synthesis of a polysaccharide intercellular adhesion. The aim of study was to investigate biofilm forming ability of Staphylococcus aureus strains by phenotypic and genotypic methods. Also Atomic Force microscope (AFM) was used to visualize biofilm formation. 140 Isolates were collected from clinical specimens of patients in Milad Hospital, Tehran and diagnosed by biochemical tests. The ability of strains to produce slime was evaluated by CRA method. For diagnosing of bacterial EPS, Indian ink staining were used and finally biofilm surface of 3 isolates observed by AFM. The prevalence of icaA and icaD genes was determined by PCR. By CRA method 15% of samples considered as positive slime producers, 44.28% as intermediate and 40.71% indicative as negative slime producers. 118 staphylococcus aureus strains showed a distinct halo transparent zone but 22 strains showed no halo zone. AFM analysis of Slime positive isolates showed a distinct and complete biofilm formation. In slime negative strain, there was not observed biofilm. The prevalence of icaA, icaD genes was 44.2% and 10% of the isolates had both genes simultaneously. There is a relationship between exopolysaccharide layer and biofilm formation of Staphylococcus aureus isolates. The presence of icaAD genes among isolates is not associated with in vitro formation of biofilm. AFM is a useful tool for observation of bacterial biofilm formation. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    Bhusari, Chitra P; Sharma, Divya S

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

  4. Diagnostic Method of Early Urolithiasis by Observing Urinary Sediments under Polarizing Microscope

    Institute of Scientific and Technical Information of China (English)

    WANG You; LI Yonglan; WANG Weimin

    2002-01-01

    Objectives The study has solved the problem of the early diagnosis of patients with the diameter of urolithiasis < 0. 3cm. Method Observed and compared urinary sediments of the 30 cases of recurrent and suspicious urolithiasis with 30 cases of nephritis, nephropyelitis and nephroma by polarizing microscope. Results The urolithiasis is diagnosed by symptoms and image. Under B ultrasound or image the diameter of stones is usually larger than 0.4cm. The disease may be certainly diagnosed but the most patients have not been able to excrete stones spontaneously. The authors observed that RBC ( erythrocytes) and casts have the characteristics of crystallization and sometime crystals formed some smaller stones( called microscope stone) in urinary sediments of the patients with recurrence stones under the polarizing microscope.Meanwhile, the sediments of suspicious patients who have symptoms of hematuria and renal colic pain and did not find stone by B ultrasound, were examined and found RBC and casts. The characteristics of crystallization were similar to those of the recurrence patients. Conclusion This method is a new way of diagnosis of early urolithiasis for preventing stone growth and treating urolithiasis as early as possible. It is very simple, convenient and reliable, and could be applied into clinic.

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

    Directory of Open Access Journals (Sweden)

    Hike Nikiyan

    2010-01-01

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

  6. Microscopic observations of self-healing products in calcareous fly ash mortars.

    Science.gov (United States)

    Jóźwiak-Niedźwiedzka, Daria

    2015-01-01

    The results of microstructural characterization of mortars containing fly ash class C (High Calcium Fly Ash) from combustion of lignite are presented. The evaluation of the microstructure was performed using scanning electron microscope, optical, and confocal microscope. The tested beams were bent till the crack and microcracks opening, which were healed during the different curing time. The results showed that the replacement of cement with fly ash class C influenced the process of crack healing. The addition of HCFA, at both 30% and 60%, speeds up the self-healing process in cracks and particularly in micro-cracks. In the research, the completely filling up of the cracks by new phases has not been observed, only the beginning of such process has been noticed.

  7. Macroscopic observables experimentally linked to microscopic processes in the explosive fracture and fragmentation of metals

    Energy Technology Data Exchange (ETDEWEB)

    Hull, Lawrence M [Los Alamos National Laboratory

    2010-12-16

    The response of a metal element to explosive loading depends on a broad spectrum of explosive and metal properties, macroscopic geometry plays a crucial role in defining the localized loading history and the resulting gradients of interest, while microscopic effects and defects are generally believed responsible for damage nucleation. Certain experiments reduce the complexity by producing conditions that are uniform in some sense, allowing dynamic measurement of variables that can be correlated with corresponding microscopic effects observed in recovery experiments. Spherical expansion of thin shells, that eventually fragment, and steady wave loading of flat plates are two such experiments. Proton radiography, x-radiography, laser velocimetry, imaging IR, and visible light photography all have produced dynamic measurements in 4340 steel, copper, uranium alloys, tantalum, and titanium. Correlation of the macroscopic measurements with microscopy on recovered samples has been done with a statistical approach.

  8. Electron microscopic observation of montmorillonite swelled by water with the aid of hydrophilic ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Chisato [Advanced Ceramics Research Center, Nagoya Institute of Technology, Honmachi 3-101-1, Tajimi, Gifu 507-0033 (Japan); Department of Pharmaceutical Engineering, School of Pharmacy, Aichi Gakuin University, Kusumoto 1-100, Chikusa, Nagoya, Aichi 464-8650 (Japan); Shirai, Takashi [Advanced Ceramics Research Center, Nagoya Institute of Technology, Honmachi 3-101-1, Tajimi, Gifu 507-0033 (Japan); Fuji, Masayoshi, E-mail: fuji@nitech.ac.jp [Advanced Ceramics Research Center, Nagoya Institute of Technology, Honmachi 3-101-1, Tajimi, Gifu 507-0033 (Japan)

    2013-09-16

    The morphology and structure of hydrous montmorillonite in different swelling condition have been observed with the aid of hydrophilic ionic liquid (IL; 1-Butyl-3-methylimidazolium Tetrafluoroborate) using electron microscope. The observation mechanism of hydrous montmorillonite with layer structure using IL was revealed by swelling behavior as measured by X-ray diffraction (XRD) and transmission electron microscopy (TEM) with selected area electron diffraction pattern (SAED). The morphology of hydrous montmorillonite containing a large amount of water was also successfully observed by field emission electron microscope (FE-SEM). In addition, the inductively coupled plasma (ICP) and thermogravimetric – differential thermal analysis (TG-DTA) results showed the ion-exchange behavior of hydrous montmorillonite during the IL treatment. The technique allowed the exact morphology to be observed of hydrated materials with layer structure in civil engineering, cosmetics, medical and agricultural fields. - Highlights: • Observation of two different conditions of hydrated montmorillonite was investigated. • The swelling structure by water molecules was characterized by TEM. • The observation mechanism of hydrous montmorillonite was revealed. • Ionic liquid is useful for characterization of hydrated materials with layer structure.

  9. Atomic force microscopic examination of chromosomes treated with trypsin or ethidium bromide.

    Science.gov (United States)

    Wu, Yangzhe; Cai, Jiye; Cheng, Longqiu; Yun, Keyu; Wang, Chenxi; Chen, Yong

    2006-04-01

    Trypsin treatment is frequently used during chromosome preparation for removal of cellular contaminants, and ethidium bromide (EB) staining of bands is often used to facilitate high-resolution observations by optical microscopy. However, conventional optical microscopy is unable to visualize potential aberrations of chromosome structures caused by these physicochemical treatments. In this article, we use atomic force microscopy (AFM) in the tapping mode to obtain and analyze high-resolution images of chromosome surface structure damage associated with trypsinization and EB treatment. According to our results, the trypsin-based digestion effects became more severe as incubations increased across a range from 10 to 40 s; a digestion time of 10 to 20 s appeared to be most suitable for observation by AFM. In terms of chromosomal damage induced by EB treatment, addition of EB into the media of cultured human blood cells induced chromosomal breakage in a dose-dependent fashion, and the results indicate centromeric region damnifyed severer than arms. Together, these results indicate that EB staining and the standard chromosomal preparative techniques of trypsinization can induce chromosomal damage that may affect the observed results.

  10. Adsorption behavior of mercury on functionalized aspergillus versicolor mycelia: atomic force microscopic study.

    Science.gov (United States)

    Das, Sujoy K; Das, Akhil R; Guha, Arun K

    2009-01-06

    The adsorption characteristics of mercury on Aspergillus versicolor mycelia have been studied under varied environments. The mycelia are functionalized by carbon disulfide (CS(2)) treatment under alkaline conditions to examine the enhance uptake capacity and explore its potentiality in pollution control management. The functionalized A. versicolor mycelia have been characterized by scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDXA), attenuated total reflection infrared (ATR-IR), and atomic force microscopy (AFM) probing. SEM and AFM images exhibit the formation of nanoparticles on the mycelial surface. ATR-IR profile confirms the functionalization of the mycelia following chemical treatment. ATR-IR and EDXA results demonstrate the binding of the sulfur groups of the functionalized mycelia to the mercury and consequent formation metal sulfide. AFM study reveals that the mycelial surface is covered by a layer of densely packed domain like structures. Sectional analysis yields significant increase in average roughness (R(rms)) value (20.5 +/- 1.82 nm) compared to that of the pristine mycelia (4.56 +/- 0.82 nm). Surface rigidity (0.88 +/- 0.06 N/m) and elasticity (92.6 +/- 10.2 MPa) obtained from a force distance curve using finite element modeling are found to increase significantly with respect to the corresponding values of (0.65 +/- 0.05 N/m and 32.8 +/- 4.5 MPa) of the nonfunctionalized mycelia. The maximum mercury adsorption capacity of the functionalized mycelia is observed to be 256.5 mg/g in comparison to 80.71 mg/g for the pristine mycelia.

  11. A measurement of the hysteresis loop in force-spectroscopy curves using a tuning-fork atomic force microscope

    Directory of Open Access Journals (Sweden)

    Manfred Lange

    2012-03-01

    Full Text Available Measurements of the frequency shift versus distance in noncontact atomic force microscopy (NC-AFM allow measurements of the force gradient between the oscillating tip and a surface (force-spectroscopy measurements. When nonconservative forces act between the tip apex and the surface the oscillation amplitude is damped. The dissipation is caused by bistabilities in the potential energy surface of the tip–sample system, and the process can be understood as a hysteresis of forces between approach and retraction of the tip. In this paper, we present the direct measurement of the whole hysteresis loop in force-spectroscopy curves at 77 K on the PTCDA/Ag/Si(111 √3 × √3 surface by means of a tuning-fork-based NC-AFM with an oscillation amplitude smaller than the distance range of the hysteresis loop. The hysteresis effect is caused by the making and breaking of a bond between PTCDA molecules on the surface and a PTCDA molecule at the tip. The corresponding energy loss was determined to be 0.57 eV by evaluation of the force–distance curves upon approach and retraction. Furthermore, a second dissipation process was identified through the damping of the oscillation while the molecule on the tip is in contact with the surface. This dissipation process occurs mainly during the retraction of the tip. It reaches a maximum value of about 0.22 eV/cycle.

  12. Color calibration of an RGB digital camera for the microscopic observation of highly specular materials

    Science.gov (United States)

    Martínez-García, Juan; Hébert, Mathieu; Trémeau, Alain

    2015-03-01

    Color calibration of imaging devices has been previously studied in a varied number of situations where the materials observed have diffuse or only slightly specular surfaces. Most of the calibration methods available in the literature consist in using standard diffuse color charts in order to determine the mathematical operations necessary to transform the colors measured by the imaging device into the reference colors obtained from the target chart. Unfortunately, there are many problems, such as sensor saturation, that arise when using these methods to calibrate devices intended for the observation of highly specular samples, especially in the 0°:0° illumination/observation geometry used in microscopic imaging systems. In this paper, we explore several color calibration methods adapted for the observation of highly specular materials, and propose one method in particular in which we use colored filters and a calibrated mirror in order to obtain a set of specular colored samples. By using 72 samples for learning, we tested the different methods on 50 other samples and obtained, with the best one, an average CIE-DeltaE94 color difference of 1.93 units, which is a fairly good performance for color measurements at the microscopic scale.

  13. Precise observation of C. elegans dynamic behaviours under controlled thermal stimulus using a mobile phone-based microscope.

    Science.gov (United States)

    Yoon, T; Shin, D-M; Kim, S; Lee, S; Lee, T G; Kim, K

    2017-04-01

    We investigated the temperature-dependent locomotion of Caenorhabditis elegans by using the mobile phone-based microscope. We developed the customized imaging system with mini incubator and smartphone to effectively control the thermal stimulation for precisely observing the temperature-dependent locomotory behaviours of C. elegans. Using the mobile phone-based microscope, we successfully followed the long-term progress of specimens of C. elegans in real time as they hatched and explored their temperature-dependent locomotory behaviour. We are convinced that the mobile phone-based microscope is a useful device for real time and long-term observations of biological samples during incubation, and can make it possible to carry out live observations via wireless communications regardless of location. In addition, this microscope has the potential for widespread use owing to its low cost and compact design. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  14. Microscopic coupled-channel calculations of nucleus-nucleus scattering including chiral three-nucleon-force effects

    CERN Document Server

    Minomo, Kosho; Ogata, Kazuyuki

    2015-01-01

    We analyze $^{16}$O-$^{16}$O and $^{12}$C-$^{12}$C scattering with the microscopic coupled-channels method and investigate the coupled-channels and three-nucleon-force (3NF) effects on elastic and inelastic cross sections. In the microscopic coupled-channels calculation, the Melbourne g-matrix interaction modified according to the chiral 3NF effects is used. It is found that the coupled-channels and 3NF effects additively change both the elastic and inelastic cross sections. As a result, the coupled-channels calculation including the 3NF effects significantly improves the agreement between the theoretical results and the experimental data. The incident-energy dependence of the coupled-channels and 3NF effects is also discussed.

  15. Observation of a single-beam gradient force acoustical trap for elastic particles: acoustical tweezers

    CERN Document Server

    Baresch, Diego; Marchiano, Régis

    2016-01-01

    The ability to manipulate matter precisely is critical for the study and development of a large variety of systems. Optical tweezers are excellent tools to handle particles ranging in size from a few micrometers to hundreds of nanometers but become inefficient and damaging on larger objects. We demonstrate for the first reported time the trapping of elastic particles by the large gradient force of a single acoustical beam in three dimensions. We show that at equal power, acoustical forces overtake by 8 orders of magnitude that of optical ones on macroscopic objects. Acoustical tweezers can push, pull and accurately control both the position of the particle and the forces exerted under damage-free conditions. The large spectrum of frequencies covered by coherent ultrasonic sources will provide a wide variety of manipulation possibilities from macro- to microscopic length scales. We believe our observations improve the prospects for wider use of non-contact manipulation in biology, biophysics, microfluidics and...

  16. Determination of the elastic moduli of thin samples and adherent cells using conical atomic force microscope tips

    Science.gov (United States)

    Gavara, Núria; Chadwick, Richard S.

    2012-12-01

    The atomic force microscope can detect the mechanical fingerprints of normal and diseased cells at the single-cell level under physiological conditions. However, atomic force microscopy studies of cell mechanics are limited by the `bottom effect' artefact that arises from the stiff substrates used to culture cells. Because cells adhered to substrates are very thin, this artefact makes cells appear stiffer than they really are. Here, we show an analytical correction that accounts for this artefact when conical tips are used for atomic force microscope measurements of thin samples. Our bottom effect cone correction (BECC) corrects the Sneddon's model, which is widely used to measure Young's modulus, E. Comparing the performance of BECC and Sneddon's model on thin polyacrylamide gels, we find that although Sneddon's model overestimates E, BECC yields E values that are thickness-independent and similar to those obtained on thick regions of the gel. The application of BECC to measurements on live adherent fibroblasts demonstrates a significant improvement on the estimation of their local mechanical properties.

  17. Graphene-coated atomic force microscope tips for reliable nanoscale electrical characterization.

    Science.gov (United States)

    Lanza, M; Bayerl, A; Gao, T; Porti, M; Nafria, M; Jing, G Y; Zhang, Y F; Liu, Z F; Duan, H L

    2013-03-13

    Graphene single-layer films are grown by chemical vapor deposition and transferred onto commercially available conductive tips for atomic force microscopy. Graphene-coated tips are much more resistant to both high currents and frictions than commercially available, metal-varnished, conductive atomic force microscopy tips, leading to much larger lifetimes and more reliable imaging due to a lower tip-sample interaction.

  18. Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth.

    Science.gov (United States)

    Pratebha, B; Jaikumar, N D; Sudhakar, R

    2014-01-01

    The cemento-dentinal junction (CDJ) is a structural and biologic link between cementum and dentin present in the roots of teeth. Conflicting reports about the origin, structure and composition of this layer are present in literature. The width of this junctional tissue is reported to be about 2-4 μm with adhesion of cementum and dentin by proteoglycans and by collagen fiber intermingling. The objective of this study is to observe and report the fibrous architecture of the CDJ of healthy tooth roots. A total of 15 healthy teeth samples were collected, sectioned into halves, demineralized in 5% ethylenediaminetetraacetic acid, processed using NaOH maceration technique and observed under a scanning electron microscope. The CDJ appeared to be a fibril poor groove with a width of 2-4 µm. Few areas of collagen fiber intermingling could be appreciated. A detailed observation of these tissues has been presented.

  19. Effect of the interaction conditions of the probe of an atomic-force microscope with the n-GaAs surface on the triboelectrization phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Baklanov, A. V., E-mail: baklanov@mail.ioffe.ru [St. Petersburg State Polytechnical University, Institute of Physics, Nanotechnology, and Telecommunications (Russian Federation); Gutkin, A. A.; Kalyuzhnyy, N. A. [Russian Academy of Sciences, Ioffe Institute (Russian Federation); Brunkov, P. N. [St. Petersburg State Polytechnical University, Institute of Physics, Nanotechnology, and Telecommunications (Russian Federation)

    2015-08-15

    Triboelectrization as a result of the scanning of an atomic-force-microscope probe over an n-GaAs surface in the contact mode is investigated. The dependences of the local potential variation on the scanning rate and the pressing force of the probe are obtained. The results are explained by point-defect formation in the surface layers of samples under the effect of deformation of these layers during probe scanning. The charge localized at these defects in the case of equilibrium changes the potential of surface, which is subject to triboelectrization. It is shown that, for qualitative explanation of the observed dependences, it is necessary to take into account both the generation and annihilation of defects in the region experiencing deformation.

  20. Tribological Characteristic of Diamond-like Carbon Films Investigated by Lateral Force Microscope

    Institute of Scientific and Technical Information of China (English)

    DINGJian-ning; ZHUShou-xing; FANZhen; LIChang-sheng; CAILan; YANGJi-chang

    2004-01-01

    Tribological characteristic of different thick diamond- like carbon (DLC) fihns was stymied. A geometrical method was applied to calibrate the cantilever spring constant and to calculate tbe normal and lateral forces, respectively. Experimental results show that the lateral force under different applied loads is proportional to the normal force for the DLC films with the thickness of 153.4nm and 64.9nm. However, for the thickness of 4.48nm and 2.78nm DLC films, lateral force is nonlinear to normal force, which is opposed to the Amonton's law. The single asperity regime and the DMT model were put forward to predict the possible nanotribological mecb-anism between the probe and DLC film.

  1. Radiation pressure excitation of a low temperature atomic force/magnetic force microscope for imaging in 4-300 K temperature range

    Science.gov (United States)

    Ćelik, Ümit; Karcı, Özgür; Uysallı, Yiǧit; Özer, H. Özgür; Oral, Ahmet

    2017-01-01

    We describe a novel radiation pressure based cantilever excitation method for imaging in dynamic mode atomic force microscopy (AFM) for the first time. Piezo-excitation is the most common method for cantilever excitation, however it may cause spurious resonance peaks. Therefore, the direct excitation of the cantilever plays a crucial role in AFM imaging. A fiber optic interferometer with a 1310 nm laser was used both for the excitation of the cantilever at the resonance and the deflection measurement of the cantilever in a commercial low temperature atomic force microscope/magnetic force microscope (AFM/MFM) from NanoMagnetics Instruments. The laser power was modulated at the cantilever's resonance frequency by a digital Phase Locked Loop (PLL). The laser beam is typically modulated by ˜500 μW, and ˜141.8 nmpp oscillation amplitude is obtained in moderate vacuum levels between 4 and 300 K. We have demonstrated the performance of the radiation pressure excitation in AFM/MFM by imaging atomic steps in graphite, magnetic domains in CoPt multilayers between 4 and 300 K and Abrikosov vortex lattice in BSCCO(2212) single crystal at 4 K for the first time.

  2. Longitudinal tire force estimation based on sliding mode observer

    Energy Technology Data Exchange (ETDEWEB)

    El Hadri, A.; Cadiou, J.C.; M' Sirdi, N.K. [Versailles Univ., Paris (France). Lab. de Robotique; Beurier, G.; Delanne, Y. [Lab. Central des Ponts, Centre de Nantes (France)

    2001-07-01

    This paper presents an estimation method for vehicle longitudinal dynamics, particularly the tractive/braking force. The estimation can be used to detect a critical driving situation to improve security. It can be used also in several vehicle control systems. The main characteristics of the vehicle longitudinal dynamics were taken into account in the model used to design an observer and computer simulations. The state variables are the angular wheel velocity, vehicle velocity and the longitudinal tire force. The proposed differential equation of the tractive/braking force is derived using the concept of relaxation length. The observer designed is based on the sliding mode approach using only the angular wheel velocity measurement. The proposed method of estimation is verified through a one-wheel simulation model with a ''Magic formula'' tire model. Simulations results show an excellent reconstruction of the tire force. (orig.)

  3. On estimating the force-freeness based on observed magnetograms

    CERN Document Server

    Zhang, X M; Su, J T

    2016-01-01

    It is a common practice in the solar physics community to test whether or not measured photospheric or chromospheric vector magnetograms are force-free, using the Maxwell stress as a measure. Some previous studies have suggested that magnetic fields of active regions in the solar chromosphere are close to be force-free whereas there is no consistency among previous studies on whether magnetic fields of active regions in the solar photosphere are force-free or not. Here we use three kinds of representative magnetic fields (analytical force-free solutions, modeled solar-like force-free fields and observed non-force-free fields) to discuss on how the measurement issues such as limited field of view, instrument sensitivity and measurement error could affect the estimation of force-freeness based on observed magnetograms. Unlike previous studies that focus on discussing the effect of limited field of view or instrument sensitivity, our calculation shows that just measurement error alone can significantly influence...

  4. Possibility of microscopic liquid water formation at landing sites on Mars and their observational potential

    CERN Document Server

    Pál, B

    2016-01-01

    Microscopic liquid brines, especially calcium-perchlorate could emerge by deliquescence on Mars during night time hours. Using climate model computations and orbital humidity observations, the ideal periods and their annual plus daily characteristics at various past, current and future landing sites were compared. Such results provide context for future analysis and targeting the related observations by the next missions for Mars. Based on the analysis, at most (but not all) past missions' landing sites, microscopic brine could emerge during night time for different durations. Analysing the conditions at ExoMars rover's primary landing site at Oxia Planum, the best annual period was found to be between $L_s$ 115 - 225, and in $Local\\hspace{0.1cm} Time$ 2 - 5, after midnight. In an ideal case, 4 hours of continuous liquid phase can emerge there. Local conditions might cause values to differ from those estimated by the model. Thermal inertia could especially make such differences (low TI values favour fast cool...

  5. Improving the electrical performance of a conductive atomic force microscope with a logarithmic current-to-voltage converter

    Science.gov (United States)

    Aguilera, L.; Lanza, M.; Porti, M.; Grifoll, J.; Nafría, M.; Aymerich, X.

    2008-07-01

    A new configuration of conductive atomic force microscope (CAFM) is presented, which is based in a standard CAFM where the typical I-V converter has been replaced by a logI-V amplifier. This substitution extends the current dynamic range from 1-100pAto1pA -1mA. With the broadening of the current dynamic range, the CAFM can access new applications, such as the reliability evaluation of metal-oxide-semiconductor gate dielectrics. As an example, the setup has been tested by analyzing breakdown spots induced in SiO2 layers.

  6. Preparation of La-Ti Composite Oxide Nanocrystal and Examination of Their Surface Topography with Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    With sol-gel method, nanometer La-Ti composite oxide was successfully prepared at a low temperature (750~800℃) using polyethylene glycol as dispersant. By means of atomic force microscope, the surface pattern, particle size distribution, and specific surface area were studied. The compound particle surface appears as a smooth sheet, the mean size of the compound is 25.38 nm. On the specific surface, the particle erects at a height of 4.69 nm. The surface area is 58.90 nm2. The La-Ti composite oxide nanocrystal prefers to narrow and even particle size distribution and the homogeneity of surface topography.

  7. Modification of a YBa2Cu3O7-δ Thin Film Using an Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    尤立星; 尹晓波; 冯一军; 杨森祖; 康琳; 王牧; 吴培亨

    2002-01-01

    A YBa2Cu3O7-δ thin film is modified by a probe electric field of an atomic force microscope to form a ridge with the width of only a grain cell. The modification varies with the operation parameters of the bias voltage,the moving velocity of the probe and the ambient humidity. Energy dispersive spectroscopy analysis shows only oxygen deficiency in the modified YBCO thin film. As a result, the suppressed superconductivity was found in the junction crossing the ridge.

  8. Effects of a slow harmonic displacement on an Atomic Force Microscope system under Lennard-Jones forces

    Directory of Open Access Journals (Sweden)

    Khadraoui Morad

    2016-01-01

    Full Text Available We focus in this paper on the modeling and dynamical analysis of a tapping mode atomic force microscopy (AFM. The microbeam is subjected to a low frequency harmonic displacement of its base and to the Lennard-Jones (LJ forces at its free end. Static and modal analysis are performed for various gaps between the tip of the microbeam and a sample. The Galerkin method is employed to reduce the equations of motion to a fast-slow dynamical system. We show that the dynamics of the AFM system is governed by the contact and the noncontact invariant slow manifolds. The tapping mode is triggered via two saddle-node bifurcations of these manifolds. Moreover, the contact time is computed and the effects of the base motion amplitude and the initial gap are discussed.

  9. Scanning electron microscopic observation: three-dimensional architecture of the collagen in hepatic fibrosis rats

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-hong; ZHAO Jing; ZHANG Wei-guang; ZHANG Li-ying; MA Rui-qiong; WANG Li-qin; ZHANG Shu-yong; TIAN Long

    2007-01-01

    Background In the process of hepatic fibrosis, the accumulation of collagen fibers is strongly related to the hepatic function. The aim of this study was to investigate the three-dimensional architecture of the collagen network in the liver of rats with hepatic fibrosis.Methods Healthy adult male Wistar rats (n=32) were randomly divided into a control group (n=16) and a hepatic fibrosis group (n=16). In the control group, the rats were treated with peanut oil while the rats in hepatic fibrosis group were treated for 10 weeks with 60% CCl4 diluted in peanut oil. The quantity of collagen fibers was detected by Western blotting; distribution of the collagen was detected by sirius red staining and polarized microscope; the three-dimensional architecture of collagen in the liver was observed under the scanning electron microscope after fixed tissues were treated with cell-maceration using NaOH. Statistical analysis was performed using the u test.Results The quantity of collagen fibers increased significantly in the hepatic fibrosis group. With the aggravation of hepatic fibrosis, collagen fibers gradually accumulated. They interlaced the reticulation compartment and formed a round or ellipse liver tissue conglomeration like a grape framework that was disparate and wrapped up the normal liver Iobule.The deposition of collagen fibers was obvious in adjacent hepatic parenchyma, especially around the portal tracts.Conclusion Our experiment showed the collagen proliferation and displays clearly the three-dimensional architecture of collagen fibers in rat liver with hepatic fibrosis by scanning electron microscope. It can provide a morphological foundation for the mechanisms of changed haemodynamics and portal hypertension in hepatic fibrosis.

  10. High resolution transmission electron microscope observation of zero-strain deformation twinning mechanisms in Ag.

    Science.gov (United States)

    Liu, L; Wang, J; Gong, S K; Mao, S X

    2011-04-29

    We have observed a new deformation-twinning mechanism using the high resolution transmission electron microscope in polycrystalline Ag films, zero-strain twinning via nucleation, and the migration of a Σ3{112} incoherent twin boundary (ITB). This twinning mechanism produces a near zero macroscopic strain because the net Burgers vectors either equal zero or are equivalent to a Shockley partial dislocation. This observation provides new insight into the understanding of deformation twinning and confirms a previous hypothesis: detwinning could be accomplished via the nucleation and migration of Σ3{112} ITBs. The zero-strain twinning mechanism may be unique to low staking fault energy metals with implications for their deformation behavior.

  11. High-resolution nanomechanical analysis of suspended electrospun silk fibers with the torsional harmonic atomic force microscope

    Directory of Open Access Journals (Sweden)

    Mark Cronin-Golomb

    2013-04-01

    Full Text Available Atomic force microscopes have become indispensable tools for mechanical characterization of nanoscale and submicron structures. However, materials with complex geometries, such as electrospun fiber networks used for tissue scaffolds, still pose challenges due to the influence of tension and bending modulus on the response of the suspended structures. Here we report mechanical measurements on electrospun silk fibers with various treatments that allow discriminating among the different mechanisms that determine the mechanical behavior of these complex structures. In particular we were able to identify the role of tension and boundary conditions (pinned versus clamped in determining the mechanical response of electrospun silk fibers. Our findings show that high-resolution mechanical imaging with torsional harmonic atomic force microscopy provides a reliable method to investigate the mechanics of materials with complex geometries.

  12. Temperature and non-linear response of cantilever-type mechanical oscillators used in atomic force microscopes with interferometric detection

    Energy Technology Data Exchange (ETDEWEB)

    Fläschner, G.; Ruschmeier, K.; Schwarz, A., E-mail: aschwarz@physnet.uni-hamburg.de; Wiesendanger, R. [Institut für Angewandte Physik, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg (Germany); Bakhtiari, M. R.; Thorwart, M. [I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstrae 9, 20355 Hamburg (Germany)

    2015-03-23

    The sensitivity of atomic force microscopes is fundamentally limited by the cantilever temperature, which can be, in principle, determined by measuring its thermal spectrum and applying the equipartition theorem. However, the mechanical response can be affected by the light field inside the cavity of a Fabry-Perot interferometer due to light absorption, radiation pressure, photothermal forces, and laser noise. By evaluating the optomechanical Hamiltonian, we are able to explain the peculiar distance dependence of the mechanical quality factor as well as the appearance of thermal spectra with symmetrical Lorentzian as well as asymmetrical Fano line shapes. Our results can be applied to any type of mechanical oscillator in an interferometer-based detection system.

  13. Bias-assisted atomic force microscope nanolithography on NbS2 thin films grown by chemical vapor deposition

    Science.gov (United States)

    Bark, Hunyoung; Kwon, Sanghyuk; Lee, Changgu

    2016-12-01

    Niobium disulfide, one of the metallic transition metal dichalcogenides, has a high potential as an electrode material for electronic devices made of 2D materials. Here, we investigated the bias-assisted atomic force microscope nanolithography of NbS2 thin films synthesized by chemical vapor deposition. We analyzed the lithographed pattern using Raman spectroscopy, transmission electron microscopy and friction force microscopy. These analyses showed that lines having various widths and thicknesses could be generated using the lithography technique by simply varying the scan speed and applied voltage. These analyses also revealed that the NbS2 film transformed from a layered crystalline structure into an amorphous structure upon being lithographed. By generating four line segments forming a square and measuring I/V curves inside and outside of the square, the electrical properties of the lithographed material were characterized. These analyses indicate that NbS2 became hydrogenated and an insulator upon being lithographed.

  14. Magnetization Reversal Processes in Pt/Co Multilayers Studied by a Magnetic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    张臻蓉; 韩宝善; 刘洪

    2001-01-01

    We have studied the magnetic reversal process of magnetron sputtered Pt/Co multilayers by using a magneticforce microscope with in situ bias magnetic fields. In thin films, magnetic reversal is usually dominated either bydomain nucleation or by domain wall motion. In our experiments, a series of magnetic images in situ capturedin the same area indicates that the magnetic reversal in Pt/Co multilayers is dominated by domain nucleation,instead of domain wall motion. In addition, the. local demagnetized curve was obtained by using the bearinganalysis of the domains in the series of magnetic images.

  15. Intracellular nanomanipulation by a photonic-force microscope with real-time acquisition of a 3D stiffness matrix

    Science.gov (United States)

    Bertseva, E.; Singh, A. S. G.; Lekki, J.; Thévenaz, P.; Lekka, M.; Jeney, S.; Gremaud, G.; Puttini, S.; Nowak, W.; Dietler, G.; Forró, L.; Unser, M.; Kulik, A. J.

    2009-07-01

    A traditional photonic-force microscope (PFM) results in huge sets of data, which requires tedious numerical analysis. In this paper, we propose instead an analog signal processor to attain real-time capabilities while retaining the richness of the traditional PFM data. Our system is devoted to intracellular measurements and is fully interactive through the use of a haptic joystick. Using our specialized analog hardware along with a dedicated algorithm, we can extract the full 3D stiffness matrix of the optical trap in real time, including the off-diagonal cross-terms. Our system is also capable of simultaneously recording data for subsequent offline analysis. This allows us to check that a good correlation exists between the classical analysis of stiffness and our real-time measurements. We monitor the PFM beads using an optical microscope. The force-feedback mechanism of the haptic joystick helps us in interactively guiding the bead inside living cells and collecting information from its (possibly anisotropic) environment. The instantaneous stiffness measurements are also displayed in real time on a graphical user interface. The whole system has been built and is operational; here we present early results that confirm the consistency of the real-time measurements with offline computations.

  16. Microscopic calculations based on chiral two- and three-nucleon forces for proton- and $^{4}$He-nucleus scattering

    CERN Document Server

    Toyokawa, Masakazu; Matsumoto, Takuma; Minomo, Kosho; Ogata, Kazuyuki; Kohno, Michio

    2015-01-01

    We investigate the effects of chiral three-nucleon force (3NF) on proton scattering at 65 MeV and $^{4}$He scattering at 72 MeV/nucleon from heavier targets, using the standard microscopic framework composed of the Brueckner-Hartree-Fock (BHF) method and the $g$-matrix folding model. For nuclear matter, the $g$ matrix is evaluated from chiral two-nucleon force (2NF) of N$^{3}$LO and chiral 3NF of NNLO by using the BHF method. Since the $g$ matrix thus obtained is numerical and nonlocal, an optimum local form is determined from the on-shell and near-on-shell components of $g$ matrix that are important for elastic scattering. For elastic scattering, the optical potentials are calculated by folding the local chiral $g$ matrix with projectile and target densities. This microscopic framework reproduces the experimental data without introducing any adjustable parameter. Chiral-3NF effects are small for proton scattering, but sizable for $^{4}$He scattering at middle angles where the data are available. Chiral 3NF, ...

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

    Science.gov (United States)

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

    2015-10-14

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    Atomic Force Microscopy (AFM) is a powerful technique providing 3D surface topographies with very high resolution in both lateral and vertical direction. Thanks to its relatively easy use, AFM can be well introduced in process control, gaining great advantage in research as well as in the evaluat......Atomic Force Microscopy (AFM) is a powerful technique providing 3D surface topographies with very high resolution in both lateral and vertical direction. Thanks to its relatively easy use, AFM can be well introduced in process control, gaining great advantage in research as well...

  19. Strategies for Human Tumor Virus Discoveries: from Microscopic Observation to Digital Transcriptome Subtraction

    Directory of Open Access Journals (Sweden)

    Ezra David Mirvish

    2016-05-01

    Full Text Available Over 20% of human cancers worldwide are associated with infectious agents, including viruses, bacteria, and parasites. Various methods have been used to identify human tumor viruses, including electron microscopic observations of viral particles, immunologic screening, cDNA library screening, nucleic acid hybridization, consensus PCR, viral DNA array chip, and representational difference analysis (RDA. With the Human Genome Project, a large amount of genetic information from humans and other organisms has accumulated over the last decade. Utilizing the available genetic databases, Patrick S. Moore, Yuan Chang, and colleagues developed digital transcriptome subtraction (DTS, an in silico method to sequentially subtract human sequences from tissue or cellular transcriptome, and discovered Merkel cell polyomavirus (MCV from Merkel cell carcinoma (MCC. Here we review the background and methods underlying the human tumor virus discoveries and explain how DTS was developed and used for the discovery of MCV.

  20. Atomistic observations and analyses of lattice defects in transmission electron microscopes

    CERN Document Server

    Abe, H

    2003-01-01

    The transmission electron microscope (TEM) -accelerators was developed. TEM-Accelerator made possible to observe in situ experiments of ion irradiation and implantation. The main results are the experimental proof of new lattice defects by irradiation, the formation process and synthesized conditions of carbon onion by ion implantation, the microstructure and phase transformation conditions of graphite by ion irradiated phase transformation, the irradiation damage formation process by simultaneous irradiation of electron and ion and behavior of fullerene whisker under irradiation. The microstructural evolution of defect clusters in copper irradiated with 240-keV Cu sup + ions and a high resolution electron micrograph of carbon onions synthesized by ion implantation are explained as the examples of recent researches. (S.Y.)

  1. Electron-microscope observations of mitosis and cytokinesis in multinucleate protoplasts of soybean.

    Science.gov (United States)

    Fowke, L C; Bech-Hansen, C W; Gamborg, O L; Constabel, F

    1975-08-01

    Multinucleate soybean protoplasts produced by spontaneous fusion during enzyme digestion of the cell wall initiated cell division after approximately 40 h in culture. The structure of these protoplasts during mitosis and cytokinesis was studied with both light and electron microscopes. Most nuclei did not fuse but divided synchronously. Interphase nuclei was commonly connected by short narrow nuclear bridges. At prophase and metaphase the nuclei appeared typical of those in most higher plants; technical difficulties prevented an adequate examination of protoplasts at anaphase. Telophase was characterized by cytokinesis involving phragmoplast and cell plate formation; however, complete partitioning of the cytoplasm by cell plants was not observed. Numerous coated vesicles were present near to or continuous with the cell plate and plasmalemma. The presence of a few dividing protoplasts with at least double the normal chromosome number suggests that some nuclear fusion occurred prior to mitosis. Very little cell wall material was detected at the margin of the dividing protoplasts.

  2. Influence of atomic force microscope tip-sample interaction on the study of scaling behavior

    NARCIS (Netherlands)

    Aue, J.; de Hosson, J.T.M.

    1997-01-01

    Images acquired with atomic force microscopy are based on tip-sample interaction. It is shown that using scanning probe techniques for determining scaling parameters of a surface leads to an underestimate of the actual scaling dimension, due to the dilation of tip and surface. How much we underestim

  3. A simple cryo-holder facilitates specimen observation under a conventional scanning electron microscope.

    Science.gov (United States)

    Tang, Chih-Yuan; Huang, Rong-Nan; Kuo-Huang, Ling-Long; Kuo, Tai-Chih; Yang, Ya-Yun; Lin, Ching-Yeh; Jane, Wann-Neng; Chen, Shiang-Jiuun

    2012-02-01

    A pre-cryogenic holder (cryo-holder) facilitating cryo-specimen observation under a conventional scanning electron microscope (SEM) is described. This cryo-holder includes a specimen-holding unit (the stub) and a cryogenic energy-storing unit (a composite of three cylinders assembled with a screw). After cooling, the cryo-holder can continue supplying cryogenic energy to extend the observation time for the specimen in a conventional SEM. Moreover, the cryogenic energy-storing unit could retain appropriate liquid nitrogen that can evaporate to prevent frost deposition on the surface of the specimen. This device is proved feasible for various tissues and cells, and can be applied to the fields of both biology and material science. We have employed this novel cryo-holder for observation of yeast cells, trichome, and epidermal cells in the leaf of Arabidopsis thaliana, compound eyes of insects, red blood cells, filiform papillae on the surface of rat tongue, agar medium, water molecules, penicillium, etc. All results suggested that the newly designed cryo-holder is applicable for cryo-specimen observation under a conventional SEM without cooling system. Most importantly, the design of this cryo-holder is simple and easy to operate and could adapt a conventional SEM to a plain type cryo-SEM affordable for most laboratories.

  4. Magnetic force microscope study on anisotropic NdFeB permanent magnets

    Institute of Scientific and Technical Information of China (English)

    刘薇; 蒋建华; 吴建生; 李刚

    2003-01-01

    NdFeB permanent magnets prepared by powder metallurgy were investigated using magnetic force microscopy(MFM).The excellent MFM images of sample along the surfaces parallel and perpendicular to the alignment axis were collected respectively.The results show the necessity of annealing procedure in the preparation of the samples to remove the polishing surface stress and to illustrate the real magnetic domain structure,so that the much information about both the magnetic structure and the topographic microstructure is obtained.The hard MFM tip is verified to be effective for this material especially for the sample with the examined surface parallel to alignment axis.By analyzing these well-captured magnetic force images,magnetic domains and alignment degree as well as thetopographic information such as grain size and the nonmagnetic phases at the grain boundaries were demonstrated.

  5. Scanning electron microscopic, transmission electron microscopic, and confocal laser scanning microscopic observation of fibroblasts cultured on microgrooved surfaces of bulk titanium substrata

    NARCIS (Netherlands)

    den Braber, E.T.; Jansen, Henricus V.; de Boer, Meint J.; Croes, H.J.E.; Elwenspoek, Michael Curt; Ginsel, L.A.; Jansen, J.A.

    1998-01-01

    During this study, microtechnology and plasma etching were used to produce gratings 1.0 (TiD01), 2.0 (TiD02), 5.0 (TiD05), and 10.0 µm wide (TiD10) into commercially pure titanium wafers. After incubation of rat dermal fibroblast (RDFs) on these surfaces for 3 days, the cells were observed with

  6. Lock-in technique for concurrent measurement of adhesion and friction with the scanning force microscope

    Science.gov (United States)

    Krotil, H.-U.; Stifter, Th.; Marti, O.

    2001-01-01

    Regardless of all the great progress in new scanning probe microscopy techniques, the concurrent measurement of adhesive and frictional forces with local resolution using scanning force microscopy (SFM) has not been possible until now. In this paper, we present a novel scanning probe microscopy mode, called combined dynamic x mode or CODYMode®. In CODYMode® SFM at least two oscillations with sufficiently different frequencies and amplitudes are superimposed and interact with the sample surface. This enables the concurrent measurement of the topography, adhesive and frictional forces beside further mechanical surface properties of the sample. By means of the characterization of plasma treated biaxially oriented polypropylene foils the benefits of the new modulation technique are pointed out where common SFM techniques are not adequate. As second application high-velocity friction experiments (in the range of several centimeters per second) on silicon under controlled environmental conditions are introduced and the role of the native water film on it is discussed under friction and viscoelastic aspects.

  7. Modified atomic force microscope applied to the measurement of elastic modulus for a single peptide molecule

    Science.gov (United States)

    Ptak, Arkadiusz; Takeda, Seiji; Nakamura, Chikashi; Miyake, Jun; Kageshima, Masami; Jarvis, Suzanne P.; Tokumoto, Hiroshi

    2001-09-01

    A modified atomic force microscopy (AFM) system, based on a force modulation technique, has been used to find an approximate value for the elastic modulus of a single peptide molecule directly from a mechanical test. For this purpose a self-assembled monolayer built from two kinds of peptides, reactive (able to anchor to the AFM tip) and nonreactive, was synthesized. In a typical experiment a single C3K30C (C=cysteine, K=lysine) peptide molecule was stretched between a Au(111) substrate and the gold-coated tip of an AFM cantilever to which it was attached via gold-sulfur bonds. The amplitude of the cantilever oscillations, due to an external force applied via a magnetic particle to the cantilever, was recorded by a lock-in amplifier and recalculated into stiffness of the stretched molecule. A longitudinal Young's modulus for the α-helix of a single peptide molecule and for the elongated state of this molecule has been estimated. The obtained values; 1.2±0.3 and 50±15 GPa, for the peptide α-helix and elongated peptide backbone, respectively, seem to be reasonable comparing them to the Young's modulus of protein crystals and linear organic polymers. We believe this research opens up a means by which scientists can perform quantitative studies of the elastic properties of single molecule, especially of biologically important polymers like peptides or DNA.

  8. Atomic force microscope controlled topographical imaging and proximal probe thermal desorption/ionization mass spectrometry imaging.

    Science.gov (United States)

    Ovchinnikova, Olga S; Kjoller, Kevin; Hurst, Gregory B; Pelletier, Dale A; Van Berkel, Gary J

    2014-01-21

    This paper reports on the development of a hybrid atmospheric pressure atomic force microscopy/mass spectrometry imaging system utilizing nanothermal analysis probes for thermal desorption surface sampling with subsequent atmospheric pressure chemical ionization and mass analysis. The basic instrumental setup and the general operation of the system were discussed, and optimized performance metrics were presented. The ability to correlate topographic images of a surface with atomic force microscopy and a mass spectral chemical image of the same surface, utilizing the same probe without moving the sample from the system, was demonstrated. Co-registered mass spectral chemical images and atomic force microscopy topographical images were obtained from inked patterns on paper as well as from a living bacterial colony on an agar gel. Spatial resolution of the topography images based on pixel size (0.2 μm × 0.8 μm) was better than the resolution of the mass spectral images (2.5 μm × 2.0 μm), which were limited by current mass spectral data acquisition rate and system detection levels.

  9. Observations of liver cancer cells in scanning probe acoustic microscope: a preliminary study

    Science.gov (United States)

    Chen, Xiaohui; Fang, Xiaoyue; Xi, Qing; Guo, Hua; Zhang, Ning; Ding, Mingyue

    2016-04-01

    Scanning probe acoustic microscope (SPAM) can be used to acquire the morphology image as well as the non-destructive internal structures acoustic image. However, the observations of the morphology image as well as the internal structures acoustic image of liver cancer cells in SPAM are few. In this paper, we cultured 4 different types of liver cancer cells on the silicon wafer and coverslip to observe their morphology images as well as acoustic images in SPAM, and made a preliminary study of the 8 types of cells specimens (hereinafter referred to as the silicon specimens and coverslips specimens). The experimental measurement results showed that some cellular pseudopodium were observed in the morphology images of the coverslip specimens while no such cellular pseupodium were appeared in the morphology images of the silicon specimens, which concluded that the living liver cancer cells were less likely to grow on the silicon wafer. SPAM provides a rapid and sensitive visual method for studying the morphology and internal structures of the cancer cells. The proposed method can be also used to obtain the morphology and internal information in both solid and soft material wafers, such as silicon and cells, with the resolution of nanometer scale.

  10. Early and efficient detection of Mycobacterium tuberculosis in sputum by microscopic observation of broth cultures.

    Directory of Open Access Journals (Sweden)

    Benson R Kidenya

    Full Text Available Early, efficient and inexpensive methods for the detection of pulmonary tuberculosis are urgently needed for effective patient management as well as to interrupt transmission. These methods to detect M. tuberculosis in a timely and affordable way are not yet widely available in resource-limited settings. In a developing-country setting, we prospectively evaluated two methods for culturing and detecting M. tuberculosis in sputum. Sputum samples were cultured in liquid assay (micro broth culture in microplate wells and growth was detected by microscopic observation, or in Löwenstein-Jensen (LJ solid media where growth was detected by visual inspection for colonies. Sputum samples were collected from 321 tuberculosis (TB suspects attending Bugando Medical Centre, in Mwanza, Tanzania, and were cultured in parallel. Pulmonary tuberculosis cases were diagnosed using the American Thoracic Society diagnostic standards. There were a total of 200 (62.3% pulmonary tuberculosis cases. Liquid assay with microscopic detection detected a significantly higher proportion of cases than LJ solid culture: 89.0% (95% confidence interval [CI], 84.7% to 93.3% versus 77.0% (95% CI, 71.2% to 82.8% (p = 0.0007. The median turn around time to diagnose tuberculosis was significantly shorter for micro broth culture than for the LJ solid culture, 9 days (interquartile range [IQR] 7-13, versus 21 days (IQR 14-28 (p<0.0001. The cost for micro broth culture (labor inclusive in our study was US $4.56 per sample, versus US $11.35 per sample for the LJ solid culture. The liquid assay (micro broth culture is an early, feasible, and inexpensive method for detection of pulmonary tuberculosis in resource limited settings.

  11. Surface imaging microscope

    Science.gov (United States)

    Rogala, Eric W.; Bankman, Isaac N.

    2008-04-01

    The three-dimensional shapes of microscopic objects are becoming increasingly important for battlespace CBRNE sensing. Potential applications of microscopic 3D shape observations include characterization of biological weapon particles and manufacturing of micromechanical components. Aerosol signatures of stand-off lidar systems, using elastic backscatter or polarization, are dictated by the aerosol particle shapes and sizes that must be well characterized in the lab. A low-cost, fast instrument for 3D surface shape microscopy will be a valuable point sensor for biological particle sensing applications. Both the cost and imaging durations of traditional techniques such as confocal microscopes, atomic force microscopes, and electron scanning microscopes are too high. We investigated the feasibility of a low-cost, fast interferometric technique for imaging the 3D surface shape of microscopic objects at frame rates limited only by the camera in the system. The system operates at two laser wavelengths producing two fringe images collected simultaneously by a digital camera, and a specialized algorithm we developed reconstructs the surface map of the microscopic object. The current implementation assembled to test the concept and develop the new 3D reconstruction algorithm has 0.25 micron resolution in the x and y directions, and about 0.1 micron accuracy in the z direction, as tested on a microscopic glass test object manufactured with etching techniques. We describe the interferometric instrument, present the reconstruction algorithm, and discuss further development.

  12. Nuclear Pairing from Two-body Microscopic Forces: Analysis of the Cooper Pair Wavefunctions

    CERN Document Server

    Finelli, P; Holt, J W

    2014-01-01

    In a recent paper we studied the behavior of the pairing gaps $\\Delta_F$ as a function of the Fermi momentum $k_F$ for neutron and nuclear matter in all relevant angular momentum channels where superfluidity is believed to naturally emerge. The calculations employed realistic chiral nucleon-nucleon potentials with the inclusion of three-body forces and self-energy effects. In this contribution, after a detailed description of the numerical method we employed in the solution of the BCS equations, we will show a preliminary analysis of the Cooper pair wavefunctions.

  13. Micropore Structure Representation of Sandstone in Petroleum Reservoirs Using an Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    BAI Yong-Qiang; ZHU Xing; WU Jun-Zheng; BAI Wen-Guang

    2011-01-01

    @@ The pore structure of sandstone in an oil reservoir is investigated using atomic force microscopy(AFM).At nanoscale resolution,AFM images of sandstone show us the fine structure.The real height data of images display the three-dimensional space structure of sandstone effectively.The three-dimensional analysis results show that the AFM images of sandstone have unique characteristics that,like fingerprints,can identify different structural properties of sandstones.The results demonstrate that AFM is an effective method used to represent original sandstone in petroleum reservoirs,and may help geologists to appreciate the sandstone in oil reservoirs fully.

  14. Direct Microscopic And Microholographic Observations Of The Solidification Of Particles From Rapidly Stirred Melts

    Science.gov (United States)

    Smeulders, R. J.; Mischgofsky, F. H.; Frankena, H. J.

    1983-06-01

    A microscopic set-up to observe fast moving solidifying particles during stir casting is described. The set-up consists of a Ruby laser and a frequency doubled Nd3+:YAG laser, a model device of an actual stir casting apparatus filled with a transparent organic alloy, melting at a low temperature and three different recording systems. Using a neopentyl alcohol alloy as a model substance for metal alloys, the crystallization process is studied by direct observation. Pulses from both lasers are used to provide a sufficiently short exposure time to take (simultaneously) holograms, microphotographs and videorecordings of the fast moving (flow rates up to 10 ms-1) small particles with sizes in the order of 10-103 μm. Primarily solidified particles appear to have equiaxed dendritic shapes. The longest diameter of these particles attain a maximum for low stirring rates and high cooling rates. After a period of stirring, some of the dendrite tips grow and transform the particle shapes into more spherical ones. At this stage the morphology of the solidified particles shows a good similarity with stir casted metal alloys.

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

    Science.gov (United States)

    Iwata, Futoshi; Adachi, Makoto; Hashimoto, Shigetaka

    2015-10-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-07

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

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

    DEFF Research Database (Denmark)

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

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning o...... areas traced in single scans of 40 mu m x 40 mu m. The results show that surface mapping on industrial surfaces is possible using the Least Mean Square alignment provided by the AFM software....... values in the order of 1 nm. The positioning repeatability of the two horizontal axes of the CMM was determined to +/-1 mu m. Sets of four 20 mu m x 20 mu m areas were traced on fiat objects, combining the data into single 40 mu m x 40 mu m areas, and comparing the roughness values to those for the same...

  18. Sensitivity analysis of rectangular atomic force microscope cantilevers immersed in liquids based on the modified couple stress theory.

    Science.gov (United States)

    Lee, Haw-Long; Chang, Win-Jin

    2016-01-01

    The modified couple stress theory is adopted to study the sensitivity of a rectangular atomic force microscope (AFM) cantilever immersed in acetone, water, carbon tetrachloride (CCl4), and 1-butanol. The theory contains a material length scale parameter and considers the size effect in the analysis. However, this parameter is difficult to obtain via experimental measurements. In this study, a conjugate gradient method for the parameter estimation of the frequency equation is presented. The optimal method provides a quantitative approach for estimating the material length scale parameter based on the modified couple stress theory. The results show that the material length scale parameter of the AFM cantilever immersed in acetone, CCl4, water, and 1-butanol is 0, 25, 116.3, and 471 nm, respectively. In addition, the vibration sensitivities of the AFM cantilever immersed in these liquids are investigated. The results are useful for the design of AFM cantilevers immersed in liquids.

  19. A new type of horizontal atomic force microscope%卧式原子力显微镜的研制

    Institute of Scientific and Technical Information of China (English)

    张冬仙; 黄峰

    2001-01-01

    提出原子力显微镜(AFM)的新设计,讨论卧式AFM的工作原理及其性能特点,简要介绍AFM的控制电路系统及其图像扫描和图像处理软件系统,给出AFM扫描获得的部分样品的图像结果。%A new design of horizontal atomic force microscope(AFM)was developed.The principle and characteristics of the new horizontal AFM were discussed.The control circuits and software systems for image scanning and processing were introduced.Some experimental results of image acquisition by using the horizontal AFM were also presented

  20. Temperature dependence of viscosity and density of viscous liquids determined from thermal noise spectra of uncalibrated atomic force microscope cantilevers.

    Science.gov (United States)

    McLoughlin, Neal; Lee, Stephen L; Hähner, Georg

    2007-08-01

    We demonstrate that the thermal response of uncalibrated atomic force microscope cantilevers can be used to extract the density and the viscosity of viscous liquids with good accuracy. Temperature dependent thermal noise spectra were measured in water/poly(ethylene glycol) mixtures. Empirical parameters characteristic of the resonance behavior of the system were extracted from data recorded for one of the solutions at room temperature. These parameters were then employed to determine both viscosity and density values of the solutions simultaneously at different temperatures. In addition, activation energies for viscous flow were determined from the viscosity values obtained. The method presented is both fast and reliable and has the potential to be applied in connection with microfluidic systems, making macroscopic amounts of liquid and separate measurements with a viscometer and a densimeter redundant.

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

    Science.gov (United States)

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

    2011-06-01

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

  2. System design and new applications for atomic force microscope based on tunneling

    Science.gov (United States)

    Wang, X.; Liu, A. P.; Yang, X. H.

    2015-09-01

    The design of atomic force microscopy (AFM) with high resolution is introduced in this paper. Mainly, we have developed the system design of the apparatus based on tunneling. AFM.IPC-208B, this kind of apparatus combines scanning tunnel microscopy (STM) and AFM availability, and its lens body with original frame enhances the capability of the machine. In order to analyze the performance of AFM.IPC-208B, as a new tool in the field of Life Science, we make use of the system to study natural mica and molecular protein structures of Cattle-insulin and human antibody immunoglobulin G (IgG) coupled with staphylococcus protein A (SPA). As the results of new applications, the resolution of AFM.IPC-208B is proved to be 0.1 nm, and these nanometer measurement results provide much valuable information for the study of small molecular proteins and HIV experiments.

  3. Femtosecond laser irradiation of indium phosphide in air: Raman spectroscopic and atomic force microscopic investigations

    Energy Technology Data Exchange (ETDEWEB)

    Bonse, J.; Wrobel, J.M.; Brzezinka, K.-W.; Esser, N.; Kautek, W

    2002-12-30

    Surface modification and ablation of crystalline indium phosphide was performed with single and double 130 fs pulses from a Ti:sapphire laser. The morphological features resulting from laser processing, have been investigated by means of micro Raman spectroscopy as well as by optical, atomic force and scanning electron microscopy. The studies indicate amorphous, ablated and recrystallized zones on the processed surface. In the single-pulse irradiation experimentsveral different threshold fluences could be assigned to the processes of melting, ablation and polycrystalline resolidification. Residual stress has been detected within the irradiated areas. Double-pulse exposure experiments have been analyzed in order to clarify the effect of cumulative damage in the ablation process of indium phosphide.

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

    Science.gov (United States)

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

    2017-03-27

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

  5. Tire Force Estimation using a Proportional Integral Observer

    Science.gov (United States)

    Farhat, Ahmad; Koenig, Damien; Hernandez-Alcantara, Diana; Morales-Menendez, Ruben

    2017-01-01

    This paper addresses a method for detecting critical stability situations in the lateral vehicle dynamics by estimating the non-linear part of the tire forces. These forces indicate the road holding performance of the vehicle. The estimation method is based on a robust fault detection and estimation approach which minimize the disturbance and uncertainties to residual sensitivity. It consists in the design of a Proportional Integral Observer (PIO), while minimizing the well known H ∞ norm for the worst case uncertainties and disturbance attenuation, and combining a transient response specification. This multi-objective problem is formulated as a Linear Matrix Inequalities (LMI) feasibility problem where a cost function subject to LMI constraints is minimized. This approach is employed to generate a set of switched robust observers for uncertain switched systems, where the convergence of the observer is ensured using a Multiple Lyapunov Function (MLF). Whilst the forces to be estimated can not be physically measured, a simulation scenario with CarSimTM is presented to illustrate the developed method.

  6. COMPARISON OF ELECTRON MICROSCOPIC OBSERVATION BETWEEN EXPANSIVE TYPE AND INFILTRATIVE TYPE OF HEPATOCELLULAR CARCINOMA

    Institute of Scientific and Technical Information of China (English)

    HUANG Zhizhi; SHEN Yanqin; LIANG Yingrui

    1999-01-01

    Objective: To study the ultrastructure and biological characteristics of expansive type of hepatocellular carcinoma (EHCC). Methods:Examination of EHCC and infiltrative type of hepatocellular carcinoma (IHCC) (each 20 cases) by electron microscope (EM) to compare their ultrastructure. Results: The 40 cases were divided into 3 groups: 16 cases of well differentiated EIICC, 4 cases of poorly differentiated EHCC, and 20 cases of poorly differentiated IHCC. The ultrastructure of well differentiated EHCC was similar to the surrounding non-cancer hepatocytes; the characteristics of them were as follows: 1. Cell membrane was developed well and cell border was clear; 2. Round nucleus was of regular shape; nuclear membrane was smooth; 3.Nucleoli were round, regular and bigger than normal;and 4. Plentiful endoplasmic reticulum and mitochondria were well developed. The ultrastructure of poorly differentiated EHCC and IHCC were identical: 1.Membrane was poorly developed; 2. Irregular nuclei were deeply indented or iobulated and many pseudoinclusions were seen; 3. Majority of the nucleoli were big, sponges or ring-formed; 4. Organelles were plentiful or scanty and tended to be degenerated.Conclusion: Most of the EHCC were mature by EM observation; this explained the EHCC's slow growth pattern, but some still had invasive potential.

  7. Concurrent evaluation of microscopic observation of drug susceptibility assay for pulmonary and extrapulmonary tuberculosis

    Science.gov (United States)

    Zadbuke, Sonali Sudhir; Set, Reena; Khan, Nishat; Shastri, Jayanthi

    2017-01-01

    BACKGROUND: Methods for detection and drug susceptibility of tuberculosis (TB) with solid media are inexpensive but slow and laborious. Rapid methods to diagnose TB and multidrug-resistant TB (MDR-TB) are a global priority for TB control. OBJECTIVES: A study was performed to compare the sensitivity of detection of mycobacterial growth and time of culture positivity by microscopic observation of drug susceptibility (MODS) assay with that of Lowenstein–Jensen (LJ) culture in pulmonary and extrapulmonary TB and to evaluate the concordance of the susceptibilities to isoniazid (INH) and rifampicin (RIF) by MODS and proportion method on LJ. MATERIALS AND METHODS: A prospective, laboratory-based study was conducted on a total of 300 samples from suspected cases of pulmonary and extrapulmonary TB. Samples were inoculated on LJ medium as per the standard guidelines and MODS assay was performed. RESULTS: Sensitivity of MODS assay was 80% and 83.3% and specificity was 92.9% and 83.3% for pulmonary and extrapulmonary samples, respectively. Difference between mean time to detection of Mycobacterium TB (MTB) by LJ medium and MODS was statistically significant, with MODS being faster. drug susceptibility testing (DST) by MODS when compared to economic variant of proportion method was 87.87% for RIF, 90.9% for INH, and 96.96% for MDR-TB detection. CONCLUSION: MODS assay provides rapid, safe, and sensitive detection of TB faster than the existing gold standard. It is extremely promising in effectively diagnosing MDR-TB.

  8. Light and electron microscope observations on Nephroselmis gaoae sp. nov. (Prasinophyceae)

    Science.gov (United States)

    Tseng, C. K.; Jiao-Fen, Chen; Zhe-Fu, Zhang; Hui-Qi, Zhang

    1994-09-01

    Nephroselmis gaoae sp. nov. is described on the basis of light and electron microscope observations of cultured material originally collected and isolated from seawater of Jiaozhou Bay, Qingdao, China. The periplasts on the cell body and flagella are covered by five types of scales, two types on the flagella and three on the body. Among these, the morphology and the number of spines of large stellate body scales differ remarkably from those of previously described species of Nephroselmis. Apart from these, the unusual fine structure of the eyespot (stigma) is very characteristic. As in the other species of Nephroselmis, the eyespot lies immediately under the two-membraned chloroplast envelope; unlike the others, however, it is not composed of a number of osmiophilic globules, but consists of about 14 curved rod-shaped osmiophilic bodies arranged loosely and randomly. This feature distinguishes the present new species not only from the other species of Nephroselmis but also from the other motile algal species, the eyespots structure of which had been previously described.

  9. Nuclear pairing from microscopic forces: singlet channels and higher-partial waves

    CERN Document Server

    Maurizio, S; Finelli, P

    2014-01-01

    Background: An accurate description of nuclear pairing gaps is extremely important for understanding static and dynamic properties of the inner crusts of neutron stars and to explain their cooling process. Purpose: We plan to study the behavior of the pairing gaps $\\Delta_F$ as a function of the Fermi momentum $k_F$ for neutron and nuclear matter in all relevant angular momentum channels where superfluidity is believed to naturally emerge. The calculations will employ realistic chiral nucleon-nucleon potentials with the inclusion of three-body forces and self-energy effects. Methods: The superfluid states of neutron and nuclear matter are studied by solving the BCS gap equation for chiral nuclear potentials using the method suggested by Khodel et al., where the original gap equation is replaced by a coupled set of equations for the dimensionless gap function $\\chi(p)$ defined by $\\Delta(p) = \\Delta_F \\chi(p)$ and a non-linear algebraic equation for the gap magnitude $\\Delta_F = \\Delta(p_F)$ at the Fermi surfa...

  10. Continuous electrospinning of polymer nanofibers of Nylon-6 using an atomic force microscope tip.

    Science.gov (United States)

    Gururajan, Giriprasath; Sullivan, S P; Beebe, T P; Chase, D B; Rabolt, J F

    2011-08-01

    An atomic force microscopy (AFM) probe is successfully utilized as an electrospinning tip for fabricating Nylon-6 nanofibers. The nanometre-size tip enabled controlled deposition of uniform polymeric nanofibers within a 1 cm diameter area. Nylon-6 nanofibers were continuously electrospun at a solution concentration as low as 1 wt% Nylon-6 in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP). Wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC) results of the AFM electrospun fibers indicated that the nanofibers predominantly display the meta-stable γ crystalline form suggesting rapid crystallization rate during the process. In addition to precise control over fiber deposition and diameter, some of the drawbacks of conventional electrospinning such as large volume of solutions and clogging of needles can be overcome using this AFM based electrospinning technique. Lastly, a comparison of electrospun fibers from syringe-needle based electrospinning and AFM probe-tip based electrospinning indicated significant morphological and microstructural differences in the case of AFM based electrospinning.

  11. Atomic force microscopy observation on nuclear reassembly in a cell-free system

    Institute of Scientific and Technical Information of China (English)

    YANG Ning; CHEN Zhongcai; ZHANG Zhaohui; ZHU Xing; ZHAI Zhonghe; TANG Xiaowei

    2003-01-01

    Cell-free system is interesting and useful for studying nuclear assembly in mitosis. Atomic force micro- scopy (AFM), which is a simple way for imaging fixed reassemble nuclei with high resolution, has not been used in the cell-free system. In this paper, we put forward an air-drying sample preparation for AFM. Using AFM, we observed nuclear reassembly process within 100 nm resolution ina cell-free system. As a result, we found that the images were artifact-free, and with higher resolution compared with fluorescent optical microscope images. Furthermore, the morphology of membrane vesicles was obtained clearly, and a dynamic change of morphology during the vesicles' approaching to nuclear envelope was also observed, which is enlightened to understand the mechanism of nuclear envelope assembly.

  12. Multiaxial ratcheting of 20 carbon steel: Macroscopic experiments and microscopic observations

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Yawei [State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031 (China); Kang, Guozheng, E-mail: guozhengkang@yahoo.com.cn [State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu 610031 (China); Liu, Yujie; Jiang, Han [School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2013-09-15

    The multiaxial ratcheting behaviors of polycrystalline 20 ordinary carbon steel were investigated at room temperature. The macroscopic experimental results showed that the studied multiaxial ratcheting depends greatly on the mean stress, stress amplitude and loading path. The axial ratcheting strain increased with the increase of applied mean stress and stress amplitude. Apparent additional hardening was observed in the non-proportionally multiaxial cyclic loading. The multiaxial ratcheting of 20 carbon steel was lower than the corresponding uniaxial one and varies with different loading paths. Dislocation patterns and their evolutions of the multiaxial ratcheting of different loading paths were then investigated using transmission electron microscopy. The obtained images showed that, with the increasing number of loading cycles, the dislocation patterns evolved from dislocation lines and networks to dislocation tangles, walls and cells. After certain cycles, sub-grains were formed because of the re-arrangement of dislocations in the walls of cells and inside the cells since the cross slip of dislocations can be easily activated for the 20 carbon steel, a kind of body-centered cubic metal. The dislocation evolution of the multiaxial ratcheting is much quicker than that of the uniaxial one. With the reference to the uniaxial one of 20 carbon steel, the macroscopic multiaxial ratcheting behaviors can be qualitatively correlated with the microscopic observation of the dislocation patterns and their evolution. - Highlights: • Multiaxial loading hardly changes the cyclic stable feature of 20 carbon steel. • Multiaxial ratcheting of 20 carbon steel depends greatly on the load path. • Dislocation patterns evolve quicker in the multiaxial case. • The stabilized dislocation pattern is sub-grain, rather than the dislocation cell. • Sub-grains formed after certain cycles make the stable ratcheting strain rate large.

  13. Observation of immuno-labeled cells at high resolution using soft X-ray microscope at Ritsumeikan University SR Center

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, A [Nagahama Institute of Bio-Science and Technology, 1266, Tamura-cho, Nagahama, Shiga, 526-0829 (Japan); Takemoto, K; Kihara, H [Department of Physics, Kansai Medical University, 18-89 Uyamahigashi, Hirakata, Osaka, 573-1136 (Japan); Fukui, T; Yoshimura, Y; Namba, H [Department of Physical Science, Ritsumeikan University, 1-1-1, Noji-Higashi, Kusatsu, Shiga, 525-8577 (Japan); Okuno, K, E-mail: takemoto@makino.kmu.ac.j [SR Center, Ritsumeikan University, 1-1-1, Noji-Higashi Kusatsu, Shiga, 525-8577 (Japan)

    2009-09-01

    Mouse fibroblast cell line NIH3T3 cells were labeled with the heavy metal (silver and gold) and observed intracellular structure under an X-ray microscope. Microtubules, Golgi apparatus and early endosomes of NIH3T3 cells were stained with immuno-gold nanoparticles, and immuno-staining was intensified by silver or gold enhancement procedure. Using a transmission soft X-ray microscope beamline (BL12) at Ritsumeikan University SR center, we observed immuno-stained NIH3T3 cells with several wavelengths just below and above oxygen edge ({lambda} = 2.32 nm). Using this method, cytoskeleton (microtubules) and organelles (Golgi apparatus and early endosomes) were successfully imaged with high resolution. Thus, immuno-gold silver and gold enhancement technique is useful for specific labeling of intracellular structure under an X-ray microscope.

  14. Observation of immuno-labeled cells at high resolution using soft X-ray microscope at Ritsumeikan University SR Center

    Science.gov (United States)

    Yamamoto, A.; Takemoto, K.; Fukui, T.; Yoshimura, Y.; Okuno, K.; Namba, H.; Kihara, H.

    2009-09-01

    Mouse fibroblast cell line NIH3T3 cells were labeled with the heavy metal (silver and gold) and observed intracellular structure under an X-ray microscope. Microtubules, Golgi apparatus and early endosomes of NIH3T3 cells were stained with immuno-gold nanoparticles, and immuno-staining was intensified by silver or gold enhancement procedure. Using a transmission soft X-ray microscope beamline (BL12) at Ritsumeikan University SR center, we observed immuno-stained NIH3T3 cells with several wavelengths just below and above oxygen edge (λ = 2.32 nm). Using this method, cytoskeleton (microtubules) and organelles (Golgi apparatus and early endosomes) were successfully imaged with high resolution. Thus, immuno-gold silver and gold enhancement technique is useful for specific labeling of intracellular structure under an X-ray microscope.

  15. MICRO/NANO-MACHINING ON SILICON SURFACE WITH A MODIFIED ATOMIC FORCE MICROSCOPE

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To understand the deformation and removal mechanism of material on nano-scale and at ultralow loads, a systemic study on AFM micro/nano-machining on single crystal silicon is conducted. The results indicate that AFM nanomachining has a precisely dimensional controllability and a good surface quality on nanometer scale. A SEM is adopted to observe nano-machined region and chips, the results indicate that the material removal mechanisms change with the applied normal load. An XPS is used to analyze the changes of chemical composition inside and outside the nano-machined region respectively. The nano-indentation which is conducted with the same AFM diamond tip on the machined region shows a big discrepancy compared with that on the macro-scale. The calculated results show higher nano-hardness and elastic modulus than normal values. This phenomenon can be regarded as the indentation size effect(ISE).

  16. OBSERVATION OF DNA PARTIAL DENATURATION BY ATOMIC FORCE MICROSCOPY

    Institute of Scientific and Technical Information of China (English)

    Xin-hua Dai; Zhi-gang Wang; Bo Xiao; Yong-jun Zhang; Chen Wang; Chun-li Bai; Xiao-li Zhang; Jian Xu

    2004-01-01

    Atomic force microscopy was used to investigate the DNA-cetyltrimethylammonium bromide (CTAB) complexes adsorbed on highly ordered pyrolytic graphite (HOPG). These complexes, at low concentrations, can automatically spread out on the surface of HOPG. The DNA-CTAB complexes display a typically extended structure rather than a globular structure. Partially denaturated DNA produced by binding CTAB to DNA is directly observed by AFM with high resolution.The three-dimensional resolution of partially denaturated DNA obtained by AFM is not available by any other technique at present.

  17. Diagnostic accuracy of microscopic Observation Drug Susceptibility (MODS assay for pediatric tuberculosis in Hanoi, Vietnam.

    Directory of Open Access Journals (Sweden)

    Sinh Thi Tran

    Full Text Available INTRODUCTION: Microscopic [corrected] Observation Drug Susceptibility (MODS has been shown to be an effective and rapid technique for early diagnosis of tuberculosis (TB. Thus far only a limited number of studies evaluating MODS have been performed in children and in extra-pulmonary tuberculosis. This study aims to assess relative accuracy and time to positive culture of MODS for TB diagnosis in children admitted to a general pediatric hospital in Vietnam. METHODS/PRINCIPAL FINDINGS: Specimens from children with suspected TB were tested by smear, MODS and Lowenstein-Jensen agar (LJ. 1129 samples from 705 children were analyzed, including sputum (n=59, gastric aspirate (n=775, CSF (n=148, pleural fluid (n=33, BAL (n=41, tracheal fluid (n=45, other (n=28. 113 TB cases were defined based on the "clinical diagnosis" (confirmed and probable groups as the reference standard, in which 26% (n=30 were diagnosed as extra-pulmonary TB. Analysis by patient shows that the overall sensitivity and specificity of smear, LJ and MODS against "clinical diagnosis" was 8.8% and 100%, 38.9% and 100%, 46% and 99.5% respectively with MODS significantly more sensitive than LJ culture (P=0.02. When analyzed by sample type, the sensitivity of MODS was significantly higher than LJ for gastric aspirates (P=0.004. The time to detection was also significantly shorter for MODS than LJ (7 days versus 32 days, P<0.001. CONCLUSION: MODS [corrected] is a sensitive and rapid culture technique for detecting TB in children. As MODS culture can be performed at a BSL2 facility and is inexpensive, it can therefore be recommended as a routine test for children with symptoms suggestive of TB in resource-limited settings.

  18. Kesesuaian antara Metode Microscopic Observation Drug Susceptibility Assay dan Ogawa pada Biakan Mycobacterium tuberculosis

    Directory of Open Access Journals (Sweden)

    Ni Sayu Dewi B

    2011-06-01

    Full Text Available Tuberculosis (TB is a problem of public health that causing high morbidity and mortality rates in various countries in the world. The diagnosis of pulmonary tuberculosis in adults can be established based on the discovery of M. tuberculosis on smear or culture of sputum. Culture is the gold standard but the availlable method is time consuming, it is need minimal eight weeks. Microscopic observation drug susceptibility assay (MODS is one of methods for M. tuberculosis culture using liquid medium that can be a simultaneously test for M. tuberculosis drug sensitivity. The purpose of this study was to determine the conformity of the MODS method compared with Ogawa method for cultivation of M. tuberculosis in pulmonary TB patients. The cross sectional research has been conducted at Clinical Pathology Department of Dr. Hasan Sadikin Hospital, Bandung and examination of the specimen done at Health Laboratory Development Unit (BPLK, West Java Province between April to August 2010. The subjects were patients who diagnosed as pulmonary TB suspect. Each collected specimen was cultured in liquid media MODS and solid media Ogawa. To analyze the conformity of MODS and Ogawa method, Kappa coefficient of agreement was used. There were 172 specimens collected from 133 subjects. The conformity between culture results of M. tuberculosis in MODS method and in Ogawa’s method using Kappa coefficient, was high (Kappa index 0.91. The difference of growth time of M. tuberculosis significant (p=0.000, in MODS was 10.1 days (range 4–21 days and in Ogawa method was 24.8 days (range 14–35 days. Conclusion, MODS and Ogawa’s method have the relatively similar diagnostic success rate, the advantage of MODS method is, the growth of M. tuberculosis is faster than in Ogawa method.

  19. Microscopic observation of magnetic bacteria in the magnetic field of a rotating permanent magnet.

    Science.gov (United States)

    Smid, Pieter; Shcherbakov, Valeriy; Petersen, Nikolai

    2015-09-01

    Magnetotactic bacteria are ubiquitous and can be found in both freshwater and marine environments. Due to intracellular chains of magnetic single domain particles, they behave like swimming compass needles. In external magnetic fields like the Earth's magnetic field, a torque is acting on the chain. This will cause the bacterium to be rotated and aligned with the external field. The swimming direction of magnetotactic bacteria can be controlled with external magnetic fields, which makes it convenient to study them under a light microscope. Usually, a special set of coils arranged around a light microscope is used to control the swimming magnetotactic bacteria. Here, we present a simple mechanical system with a permanent magnet, which produces a rotating magnetic field of nearly constant amplitude in the focal plane of a light microscope. The device is placed beside the light microscope and easily adaptable to almost any microscope and thus convenient for field experiments. To describe the trajectories qualitatively, a theoretical model of the trajectories is presented. This device can be used to control the swimming direction of magnetotactic bacteria and also for studying their magnetic and hydrodynamic properties.

  20. Analysis of the swimming activity of Pseudomonas aeruginosa by using photonic force microscope

    Science.gov (United States)

    Chan, Chia-Han; Chang, Bo-Jui; Huang, Ying-Jung; Fan, Chia-Chieh; Peng, Hwei-Ling; Chi, Sien; Hsu, Long

    2005-08-01

    Swimming activity of flagella is a main factor of the motility of bacteria. Flagella expressed on the surface of bacterial species serve as a primary means of motility including swimming. We propose to use optical tweezers to analyze the swimming activity of bacteria. The sample bacteria in the work is Pseudomonas aeruginosa, and it is a gram-negative bacterium and often causes leading to burn wound infections, urinary-tract infections, and pneumonia. The single polar flagellum of P. aeruginosa has been demonstrated to be important virulence and colonization factor of this opportunistic pathogen. We demonstrate a gene to regulate the bacterial swimming activity in P. aeruginosa PAO1 by biological method. However, the change of flagellar morphology was not observed by electron microscopy analysis, suggesting that the gene regulates the flagellar rotation that could not be detected by biological method. PFM exhibits a spatial resolution of a few nanometers to detect the relative position of the probe at an acquisition rate over 1 MHz. By binding a probe such as a bead or a quantum dot on the flagella, we expect the rotation of the probe due to the flagella could be detected. It is expected that the study of the swimming activity of P. aeruginosa provide potent method for the pathogenic role of the flagella in P. aeruginosa.

  1. Video-microscopic observation of ionic liquid/alcohol interface and the corresponding molecular simulation study

    Science.gov (United States)

    Zhu, Peixi

    This research is aimed at studying the ionic liquid/n-pentanol interface via video-microscopy and molecular dynamic simulations. Understanding the interfacial phenomena and interfacial transport between ionic liquids and other liquids is of interest to the development and application of ionic liquids in a number of areas. One such area is the biphasic hydroformylation of alkenes to obtain alcohol and aldehyde, in which case ionic liquid is the reaction medium where a catalyst resides. The dissolution of an ionic liquid into an alcohol was studied by microscopically observing and measuring the shrinking of a micropipette-produced droplet in real time. Although microscopic investigation of droplet dissolution has been studied before, no attempt had been made to measure the diffusion coefficient D of the droplet species in the surrounding medium. A key finding of this work is that the Epstein-Plesset mathematical model, which describes the dissolution of a droplet/bubble in another fluid medium, can be used to measure D. Other experimental studies of the ionic liquid/alcohol system include electrical conductivity and UV-visible spectroscopy measurements of solutions of 1-hexyl-3-methylimidazolium tetrafluoroborate in n-pentanol. Those experiments were done in order to understand the molecular state of the particular ionic liquid in n-pentanol, as well as obtaining the dissociation constant K of such weak electrolyte solution. The experimental results provide an entry to the assessment of ionic liquid interaction with n-pentanol at molecular scale. Subsequently, molecular dynamics simulation was implemented for the investigation of such interaction. The computation started with simulation of the bulk phase of 1-butyl-3-methylimidazolium tetrafluoroborate, an affine ionic liquid on which molecular simulations had already been reported. A generalized probability based on Fuoss approximation for the closest ion to a distinguished countercharge ion was developed. In

  2. Set-up of a High-Resolution 300 mK Atomic Force Microscope in an Ultra-High Vacuum Compatible 3He/10T Cryostat

    CERN Document Server

    von Allwörden, Henning; Köhler, Arne; Eelbo, Thomas; Schwarz, Alexander; Wiesendanger, Roland

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

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

    DEFF Research Database (Denmark)

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

    1996-01-01

    Atomic force and scanning near-field optical microscopic investigations have been carried out on a polarization holographic grating recorded in an azobenzene side-chain Liquid crystalline polyester. It has been found that immediately following laser irradiation, a topographic surface grating...

  6. Chronic Chagas disease: PCR-xenodiagnosis without previous microscopic observation is a useful tool to detect viable Trypanosoma cruzi.

    Science.gov (United States)

    Saavedra, Miguel; Zulantay, Inés; Apt, Werner; Martínez, Gabriela; Rojas, Antonio; Rodríguez, Jorge

    2013-01-01

    We evaluate the elimination of the microscopic stage of conventional xenodiagnosis (XD) to optimize the parasitological diagnosis of Trypanosoma cruzi in chronic Chagas disease. To this purpose we applied under informed consent two XD cages to 150 Chilean chronic chagasic patients. The fecal samples (FS) of the triatomines at 30, 60 and 90 days post feeding were divided into two parts: in one a microscopic search for mobile trypomastigote and/or epimastigote forms was performed. In the other part, DNA extraction-purification for PCR directed to the conserved region of kDNA minicircles of trypanosomes (PCR-XD), without previous microscopic observation was done. An XD was considered positive when at least one mobile T. cruzi parasite in any one of three periods of incubation was observed, whereas PCR-XD was considered positive when the 330 bp band specific for T. cruzi was detected. 25 of 26 cases with positive conventional XD were PCR-XD positive (concordance 96.2%), whereas 85 of 124 cases with negative conventional XD were positive by PCR-XD (68.5%). Human chromosome 12 detected by Real-time PCR used as exogenous internal control of PCR-XD reaction allowed to discounting of PCR inhibition and false negative in 40 cases with negative PCR-XD. PCR-XD performed without previous microscopic observation is a useful tool for detection of viable parasites with higher efficiency then conventional XD.

  7. Whole lifespan microscopic observation of budding yeast aging through a microfluidic dissection platform

    NARCIS (Netherlands)

    Lee, Sung Sik; Avalos Vizcarra, Ima; Huberts, Daphne H E W; Lee, Luke P; Heinemann, Matthias

    2012-01-01

    Important insights into aging have been generated with the genetically tractable and short-lived budding yeast. However, it is still impossible today to continuously track cells by high-resolution microscopic imaging (e.g., fluorescent imaging) throughout their entire lifespan. Instead, the field

  8. Whole lifespan microscopic observation of budding yeast aging through a microfluidic dissection platform

    NARCIS (Netherlands)

    Lee, Sung Sik; Avalos Vizcarra, Ima; Huberts, Daphne H E W; Lee, Luke P; Heinemann, Matthias

    2012-01-01

    Important insights into aging have been generated with the genetically tractable and short-lived budding yeast. However, it is still impossible today to continuously track cells by high-resolution microscopic imaging (e.g., fluorescent imaging) throughout their entire lifespan. Instead, the field st

  9. A miniaturized, high frequency mechanical scanner for high speed atomic force microscope using suspension on dynamically determined points

    Energy Technology Data Exchange (ETDEWEB)

    Herfst, Rodolf; Dekker, Bert; Witvoet, Gert; Crowcombe, Will; Lange, Dorus de [Department of Optomechatronics, Netherlands Organization for Applied Scientific Research, TNO, Delft (Netherlands); Sadeghian, Hamed, E-mail: hamed.sadeghianmarnani@tno.nl, E-mail: h.sadeghianmarnani@tudelft.nl [Department of Optomechatronics, Netherlands Organization for Applied Scientific Research, TNO, Delft (Netherlands); Department of Precision and Microsystems Engineering, Delft University of Technology, Delft (Netherlands)

    2015-11-15

    One of the major limitations in the speed of the atomic force microscope (AFM) is the bandwidth of the mechanical scanning stage, especially in the vertical (z) direction. According to the design principles of “light and stiff” and “static determinacy,” the bandwidth of the mechanical scanner is limited by the first eigenfrequency of the AFM head in case of tip scanning and by the sample stage in terms of sample scanning. Due to stringent requirements of the system, simply pushing the first eigenfrequency to an ever higher value has reached its limitation. We have developed a miniaturized, high speed AFM scanner in which the dynamics of the z-scanning stage are made insensitive to its surrounding dynamics via suspension of it on specific dynamically determined points. This resulted in a mechanical bandwidth as high as that of the z-actuator (50 kHz) while remaining insensitive to the dynamics of its base and surroundings. The scanner allows a practical z scan range of 2.1 μm. We have demonstrated the applicability of the scanner to the high speed scanning of nanostructures.

  10. A miniaturized, high frequency mechanical scanner for high speed atomic force microscope using suspension on dynamically determined points.

    Science.gov (United States)

    Herfst, Rodolf; Dekker, Bert; Witvoet, Gert; Crowcombe, Will; de Lange, Dorus; Sadeghian, Hamed

    2015-11-01

    One of the major limitations in the speed of the atomic force microscope (AFM) is the bandwidth of the mechanical scanning stage, especially in the vertical (z) direction. According to the design principles of "light and stiff" and "static determinacy," the bandwidth of the mechanical scanner is limited by the first eigenfrequency of the AFM head in case of tip scanning and by the sample stage in terms of sample scanning. Due to stringent requirements of the system, simply pushing the first eigenfrequency to an ever higher value has reached its limitation. We have developed a miniaturized, high speed AFM scanner in which the dynamics of the z-scanning stage are made insensitive to its surrounding dynamics via suspension of it on specific dynamically determined points. This resulted in a mechanical bandwidth as high as that of the z-actuator (50 kHz) while remaining insensitive to the dynamics of its base and surroundings. The scanner allows a practical z scan range of 2.1 μm. We have demonstrated the applicability of the scanner to the high speed scanning of nanostructures.

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

    Science.gov (United States)

    Ren, Juan

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

  12. Adaptation of lift forces in object manipulation through action observation.

    Science.gov (United States)

    Reichelt, Andreas F; Ash, Alyssa M; Baugh, Lee A; Johansson, Roland S; Flanagan, J Randall

    2013-07-01

    The ability to predict accurately the weights of objects is essential for skilled and dexterous manipulation. A potentially important source of information about object weight is through the observation of other people lifting objects. Here, we tested the hypothesis that when watching an actor lift an object, people naturally learn the object's weight and use this information to scale forces when they subsequently lift the object themselves. Participants repeatedly lifted an object in turn with an actor. Object weight unpredictably changed between 2 and 7 N every 5th to 9th of the actor's lifts, and the weight lifted by the participant always matched that previously lifted by the actor. Even though the participants were uninformed about the structure of the experiment, they appropriately adapted their lifting force in the first trial after a weight change. Thus, participants updated their internal representation about the object's weight, for use in action, when watching a single lift performed by the actor. This ability presumably involves the comparison of predicted and actual sensory information related to actor's actions, a comparison process that is also fundamental in action.

  13. Oscillatory and ion-correlation forces observed in direct force measurements between silica surfaces in concentrated CaCl2 solutions

    NARCIS (Netherlands)

    Fielden, ML; Hayes, RA; Ralston, J

    2000-01-01

    The force between silica spheres and naturally oxidised silicon wafer has been measured in calcium chloride solutions at concentrations between 1 and 5 M using an atomic force microscope. An oscillatory force, consistent in periodicity with the expulsion of layers of ions, was found to overlay the e

  14. In Situ Scanning-Tunneling-Microscope Observation on Dissolution of a Cu-20Zr Film

    Institute of Scientific and Technical Information of China (English)

    Haibo LU; Guoze MENG; Ying LI; Fuhui WANG

    2005-01-01

    A nanocrystalline coating of Cu-20Zr (in wt pct) was obtained on glass by magnetron sputtering. The corrosion behavior of the Cu-20Zr film in 0.001 mol/L HCl solution was investigated using potentiodynamic polarization and in situ electrochemical scanning-tunneling-microscopy (ECSTM). Results demonstrated that the film exhibits active behavior. Microscopic pitting corrosion and tunneling are caused by localized electrodissolution of Zr atoms and the diffusion of Cu atoms at surface defects.

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

    Science.gov (United States)

    Ruppert, Michael G.; Yong, Yuen K.

    2017-08-01

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

  16. Line-edge quality optimization of electron beam resist for high-throughput character projection exposure utilizing atomic force microscope analysis

    Science.gov (United States)

    Ikeno, Rimon; Mita, Yoshio; Asada, Kunihiro

    2017-04-01

    High-throughput electron-beam lithography (EBL) by character projection (CP) and variable-shaped beam (VSB) methods is a promising technique for low-to-medium volume device fabrication with regularly arranged layouts, such as standard-cell logics and memory arrays. However, non-VLSI applications like MEMS and MOEMS may not fully utilize the benefits of CP method due to their wide variety of layout figures including curved and oblique edges. In addition, the stepwise shapes that appear on such irregular edges by VSB exposure often result in intolerable edge roughness, which may degrade performances of the fabricated devices. In our former study, we proposed a general EBL methodology for such applications utilizing a combination of CP and VSB methods, and demonstrated its capabilities in electron beam (EB) shot reduction and edge-quality improvement by using a leading-edge EB exposure tool, ADVANTEST F7000S-VD02, and high-resolution Hydrogen Silsesquioxane resist. Both scanning electron microscope and atomic force microscope observations were used to analyze quality of the resist edge profiles to determine the influence of the control parameters used in the exposure-data preparation process. In this study, we carried out detailed analysis of the captured edge profiles utilizing Fourier analysis, and successfully distinguish the systematic undulation by the exposed CP character profiles from random roughness components. Such capability of precise edge-roughness analysis is useful to our EBL methodology to maintain both the line-edge quality and the exposure throughput by optimizing the control parameters in the layout data conversion.

  17. Method for Measuring the Distribution of Adhesion Forces on Continuous Nanoscale Protrusions Using Carbon Nanofiber Tip on a Scanning Probe Microscope Cantilever.

    Science.gov (United States)

    Shimoi, Norihiro; Abe, Daisuke

    2015-07-01

    The adhesion force on surfaces has received attention in numerous scientific and technological fields, including catalysis, thin-film growth, and tribology. Many applications require knowledge of the strength of these forces as a function of position in three dimensions, but until now such information has only been theoretically proposed. Here, we demonstrate an approach based on scanning probe microscopy that can obtain such data and be used to image the three-dimensional surface force field of continuous nanoscale protrusions. We present adhesion force maps with nanometer and nanonewton resolution that allow detailed characterization of the interaction between a surface and a thin carbon nanofiber (CNF) rod synthesized by plasma-enhanced chemical vapor deposition (PECVD) at the end of a tip on a scanning probe microscope cantilever in three dimensions. In these maps, the positions of all continuous nanoscale protrusions are identified and the differences in the adhesive forces among limited areas at inequivalent sites are quantified.

  18. High-speed spiral imaging technique for an atomic force microscope using a linear quadratic Gaussian controller

    Science.gov (United States)

    Habibullah, H.; Pota, H. R.; Petersen, I. R.

    2014-03-01

    This paper demonstrates a high-speed spiral imaging technique for an atomic force microscope (AFM). As an alternative to traditional raster scanning, an approach of gradient pulsing using a spiral line is implemented and spirals are generated by applying single-frequency cosine and sine waves of slowly varying amplitudes to the X and Y-axes of the AFM's piezoelectric tube scanner (PTS). Due to these single-frequency sinusoidal input signals, the scanning process can be faster than that of conventional raster scanning. A linear quadratic Gaussian controller is designed to track the reference sinusoid and a vibration compensator is combined to damp the resonant mode of the PTS. An internal model of the reference sinusoidal signal is included in the plant model and an integrator for the system error is introduced in the proposed control scheme. As a result, the phase error between the input and output sinusoids from the X and Y-PTSs is reduced. The spirals produced have particularly narrow-band frequency measures which change slowly over time, thereby making it possible for the scanner to achieve improved tracking and continuous high-speed scanning rather than being restricted to the back and forth motion of raster scanning. As part of the post-processing of the experimental data, a fifth-order Butterworth filter is used to filter noises in the signals emanating from the position sensors and a Gaussian image filter is used to filter the images. A comparison of images scanned using the proposed controller (spiral) and the AFM PI controller (raster) shows improvement in the scanning rate using the proposed method.

  19. High-speed spiral imaging technique for an atomic force microscope using a linear quadratic Gaussian controller

    Energy Technology Data Exchange (ETDEWEB)

    Habibullah, H., E-mail: h.habib@student.adfa.edu.au; Pota, H. R., E-mail: h.pota@adfa.edu.au; Petersen, I. R., E-mail: i.petersen@adfa.edu.au [School of Engineering and Information Technology, University of New South Wales, Canberra, Australian Capital Territory 2612 (Australia)

    2014-03-15

    This paper demonstrates a high-speed spiral imaging technique for an atomic force microscope (AFM). As an alternative to traditional raster scanning, an approach of gradient pulsing using a spiral line is implemented and spirals are generated by applying single-frequency cosine and sine waves of slowly varying amplitudes to the X and Y-axes of the AFM’s piezoelectric tube scanner (PTS). Due to these single-frequency sinusoidal input signals, the scanning process can be faster than that of conventional raster scanning. A linear quadratic Gaussian controller is designed to track the reference sinusoid and a vibration compensator is combined to damp the resonant mode of the PTS. An internal model of the reference sinusoidal signal is included in the plant model and an integrator for the system error is introduced in the proposed control scheme. As a result, the phase error between the input and output sinusoids from the X and Y-PTSs is reduced. The spirals produced have particularly narrow-band frequency measures which change slowly over time, thereby making it possible for the scanner to achieve improved tracking and continuous high-speed scanning rather than being restricted to the back and forth motion of raster scanning. As part of the post-processing of the experimental data, a fifth-order Butterworth filter is used to filter noises in the signals emanating from the position sensors and a Gaussian image filter is used to filter the images. A comparison of images scanned using the proposed controller (spiral) and the AFM PI controller (raster) shows improvement in the scanning rate using the proposed method.

  20. High-speed spiral imaging technique for an atomic force microscope using a linear quadratic Gaussian controller.

    Science.gov (United States)

    Habibullah, H; Pota, H R; Petersen, I R

    2014-03-01

    This paper demonstrates a high-speed spiral imaging technique for an atomic force microscope (AFM). As an alternative to traditional raster scanning, an approach of gradient pulsing using a spiral line is implemented and spirals are generated by applying single-frequency cosine and sine waves of slowly varying amplitudes to the X and Y-axes of the AFM's piezoelectric tube scanner (PTS). Due to these single-frequency sinusoidal input signals, the scanning process can be faster than that of conventional raster scanning. A linear quadratic Gaussian controller is designed to track the reference sinusoid and a vibration compensator is combined to damp the resonant mode of the PTS. An internal model of the reference sinusoidal signal is included in the plant model and an integrator for the system error is introduced in the proposed control scheme. As a result, the phase error between the input and output sinusoids from the X and Y-PTSs is reduced. The spirals produced have particularly narrow-band frequency measures which change slowly over time, thereby making it possible for the scanner to achieve improved tracking and continuous high-speed scanning rather than being restricted to the back and forth motion of raster scanning. As part of the post-processing of the experimental data, a fifth-order Butterworth filter is used to filter noises in the signals emanating from the position sensors and a Gaussian image filter is used to filter the images. A comparison of images scanned using the proposed controller (spiral) and the AFM PI controller (raster) shows improvement in the scanning rate using the proposed method.

  1. Electrical conductivity in Langmuir-Blodgett films of n-alkyl cyanobiphenyls using current sensing atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Gayathri, H. N.; Suresh, K. A., E-mail: suresh@cnsms.res.in [Centre for Nano and Soft Matter Sciences, P. B. No. 1329, Jalahalli, Bangalore 560013 (India)

    2015-06-28

    We report our studies on the nanoscale electrical conductivity in monolayers of n-alkyl cyanobiphenyl materials deposited on solid surface. Initially, the 8CB, 9CB, and 10CB monolayer films were prepared by the Langmuir technique at air-water interface and characterized by surface manometry and Brewster angle microscopy. The monolayer films were transferred on to solid substrates by the Langmuir-Blodgett (L-B) technique. The 8CB, 9CB, and 10CB monolayer L-B films were deposited on freshly cleaved mica and studied by atomic force microscope (AFM), thereby measuring the film thickness as ∼1.5 nm. The electrical conductivity measurements were carried out on 9CB and 10CB monolayer L-B films deposited onto highly ordered pyrolytic graphite using current sensing AFM. The nanoscale current-voltage (I-V) measurements show a non-linear variation. The nature of the curve indicates electron tunneling to be the mechanism for electrical conduction. Furthermore, analysis of the I-V curve reveals a transition in the electron conduction mechanism from direct tunneling to injection tunneling. From the transition voltage, we have estimated the values of barrier height for 9CB and 10CB to be 0.71 eV and 0.37 eV, respectively. For both 9CB and 10CB, the effective mass of electron was calculated to be 0.021 m{sub e} and 0.065 m{sub e}, respectively. These parameters are important in the design of molecular electronic devices.

  2. Nanoscale observation of organic thin film by atomic force microscopy

    Science.gov (United States)

    Mochizuki, Shota; Uruma, Takeshi; Satoh, Nobuo; Saravanan, Shanmugam; Soga, Tetsuo

    2017-08-01

    Organic photovoltaics (OPVs) fabricated using organic semiconductors and hybrid solar cells (HSCs) based on organic semiconductors/quantum dots (QDs) have been attracting significant attention owing to their potential use in low-cost solar energy-harvesting applications and flexible, light-weight, colorful, large-area devices. In this study, we observed and evaluated the surface of a photoelectric conversion layer (active layer) of the OPVs and HSCs based on phenyl-C61-butyric acid methyl ester (PCBM), poly(3-hexylthiophene) (P3HT), and zinc oxide (ZnO) nanoparticles. The experiment was performed using atomic force microscopy (AFM) combined with a frequency modulation detector (FM detector) and a contact potential difference (CPD) detection circuit. We experimentally confirmed the changes in film thickness and surface potential, as affected by the ZnO nanoparticle concentration. From the experimental results, we confirmed that ZnO nanoparticles possibly affect the structures of PCBM and P3HT. Also, we prepared an energy band diagram on the basis of the observation results, and analyzed the energy distribution inside the active layer.

  3. Pancam and Microscopic Imager observations of dust on the Spirit Rover: Cleaning events, spectral properties, and aggregates

    Science.gov (United States)

    Vaughan, Alicia F.; Johnson, Jeffrey R.; Herkenhoff, Kenneth E.; Sullivan, Robert; Landis, Geoffrey A.; Goetz, Walter; Madsen, Morten B.

    2010-01-01

    This work describes dust deposits on the Spirit Rover over 2000 sols through examination of Pancam and Microscopic Imager observations of specific locations on the rover body, including portions of the solar array, Pancam and Mini-TES calibration targets, and the magnets. This data set reveals the three "cleaning events" experienced by Spirit to date, the spectral properties of dust, and the tendency of dust particles to form aggregates 100 um and larger.

  4. Electron microscopic observation of LE/LC phase transition in dipalmitoyl phosphatidylcholine monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Neuman, R.D.; Fereshtehkhou, S.; Ovalle, R.

    1984-10-01

    The monolayer structure of L-..cap alpha..-dipalmitoyl phosphatidylcholine (DPPC) at the air/water interface was examined using improved electron microscopic techniques. The DPPC monolayer is homogeneous in both the liquid-expanded (LE) and liquid-condensed (LC) states. In the intermediate LE/LC region, however, the monolayer is nonhomogeneous and biphasic. The results of two coexisting phases are consistent with the interpretation of a first-order phase transition occurring between the LE and LC states in monomolecular films. 20 references, 2 figures.

  5. The Cassie-Wenzel transition of fluids on nanostructured substrates: Macroscopic force balance versus microscopic density-functional theory

    Science.gov (United States)

    Tretyakov, Nikita; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen; Dünweg, Burkhard; Daoulas, Kostas Ch.

    2016-10-01

    Classical density functional theory is applied to investigate the validity of a phenomenological force-balance description of the stability of the Cassie state of liquids on substrates with nanoscale corrugation. A bulk free-energy functional of third order in local density is combined with a square-gradient term, describing the liquid-vapor interface. The bulk free energy is parameterized to reproduce the liquid density and the compressibility of water. The square-gradient term is adjusted to model the width of the water-vapor interface. The substrate is modeled by an external potential, based upon the Lennard-Jones interactions. The three-dimensional calculation focuses on substrates patterned with nanostripes and square-shaped nanopillars. Using both the force-balance relation and density-functional theory, we locate the Cassie-to-Wenzel transition as a function of the corrugation parameters. We demonstrate that the force-balance relation gives a qualitatively reasonable description of the transition even on the nanoscale. The force balance utilizes an effective contact angle between the fluid and the vertical wall of the corrugation to parameterize the impalement pressure. This effective angle is found to have values smaller than the Young contact angle. This observation corresponds to an impalement pressure that is smaller than the value predicted by macroscopic theory. Therefore, this effective angle embodies effects specific to nanoscopically corrugated surfaces, including the finite range of the liquid-solid potential (which has both repulsive and attractive parts), line tension, and the finite interface thickness. Consistently with this picture, both patterns (stripes and pillars) yield the same effective contact angles for large periods of corrugation.

  6. Development of an Integrated Microfluidic Perfusion Cell Culture System for Real-Time Microscopic Observation of Biological Cells

    Directory of Open Access Journals (Sweden)

    Chih-Chin Oh-Yang

    2011-08-01

    Full Text Available This study reports an integrated microfluidic perfusion cell culture system consisting of a microfluidic cell culture chip, and an indium tin oxide (ITO glass-based microheater chip for micro-scale perfusion cell culture, and its real-time microscopic observation. The system features in maintaining both uniform, and stable chemical or thermal environments, and providing a backflow-free medium pumping, and a precise thermal control functions. In this work, the performance of the medium pumping scheme, and the ITO glass microheater were experimentally evaluated. Results show that the medium delivery mechanism was able to provide pumping rates ranging from 15.4 to 120.0 μL·min−1. In addition, numerical simulation and experimental evaluation were conducted to verify that the ITO glass microheater was capable of providing a spatially uniform thermal environment, and precise temperature control with a mild variation of ±0.3 °C. Furthermore, a perfusion cell culture was successfully demonstrated, showing the cultured cells were kept at high cell viability of 95 ± 2%. In the process, the cultured chondrocytes can be clearly visualized microscopically. As a whole, the proposed cell culture system has paved an alternative route to carry out real-time microscopic observation of biological cells in a simple, user-friendly, and low cost manner.

  7. Force-Mediated Kinetics of Single P-Selectin/Ligand Complexes Observed by Atomic Force Microscopy

    Science.gov (United States)

    Fritz, Jurgen; Katopodis, Andreas G.; Kolbinger, Frank; Anselmetti, Dario

    1998-10-01

    Leukocytes roll along the endothelium of postcapillary venules in response to inflammatory signals. Rolling under the hydrodynamic drag forces of blood flow is mediated by the interaction between selectins and their ligands across the leukocyte and endothelial cell surfaces. Here we present force-spectroscopy experiments on single complexes of P-selectin and P-selectin glycoprotein ligand-1 by atomic force microscopy to determine the intrinsic molecular properties of this dynamic adhesion process. By modeling intermolecular and intramolecular forces as well as the adhesion probability in atomic force microscopy experiments we gain information on rupture forces, elasticity, and kinetics of the P-selectin/P-selectin glycoprotein ligand-1 interaction. The complexes are able to withstand forces up to 165 pN and show a chain-like elasticity with a molecular spring constant of 5.3 pN nm-1 and a persistence length of 0.35 nm. The dissociation constant (off-rate) varies over three orders of magnitude from 0.02 s-1 under zero force up to 15 s-1 under external applied forces. Rupture force and lifetime of the complexes are not constant, but directly depend on the applied force per unit time, which is a product of the intrinsic molecular elasticity and the external pulling velocity. The high strength of binding combined with force-dependent rate constants and high molecular elasticity are tailored to support physiological leukocyte rolling.

  8. 'Sub-atomic' resolution of non-contact atomic force microscope images induced by a heterogeneous tip structure: a density functional theory study.

    Science.gov (United States)

    Campbellová, Anna; Ondráček, Martin; Pou, Pablo; Pérez, Rubén; Klapetek, Petr; Jelínek, Pavel

    2011-07-22

    A Si adatom on a Si(111)-(7 × 7) reconstructed surface is a typical atomic feature that can rather easily be imaged by a non-contact atomic force microscope (nc-AFM) and can be thus used to test the atomic resolution of the microscope. Based on our first principles density functional theory (DFT) calculations, we demonstrate that the structure of the termination of the AFM tip plays a decisive role in determining the appearance of the adatom image. We show how the AFM image changes depending on the tip-surface distance and the composition of the atomic apex at the end of the tip. We also demonstrate that contaminated tips may give rise to image patterns displaying so-called 'sub-atomic' features even in the attractive force regime.

  9. The effects of two-dimensional bifurcations and quantum beats in a system of combined atomic force and scanning tunneling microscopes with quantum dots

    Science.gov (United States)

    Zhukovsky, V. Ch.; Krevchik, V. D.; Semenov, M. B.; Krevchik, P. V.; Zaytsev, R. V.; Egorov, I. A.

    2016-11-01

    The field and temperature dependence of the probability of two-dimensional dissipative tunneling is studied in the framework of one-instanton approximation for a model double-well oscillator potential in an external electric field at finite temperature with account for the influence of two local phonon modes for quantum dots in a system of a combined atomic force and a scanning tunneling microscope. It is demonstrated that in the mode of synchronous parallel transfer of tunneling particles from the cantilever tip to the quantum dot the two local phonon modes result in the occurrence of two stable peaks in the curve of the 2D dissipative tunneling probability as a function of the field. Qualitative comparison of the theoretical curve in the limit of weak dissociation and the experimental current-voltage characteristic for quantum dots that grow from colloidal gold under a cantilever tip at the initial stage of quantum-dot formation when the quantum dot size does not exceed 10 nm is performed. It is established that one of the two stable peaks that correspond to interaction of tunneling particles with two local phonon modes in the temperature dependence of the 2D dissipative tunneling probability can be split in two, which corresponds to the tunneling channel interference mechanism. It is found that the theoretically predicted and experimentally observed mode of quantum beats occurs near the bifurcation point.

  10. Functionalization of undoped and p-doped Si (100) using atomic force microscope tips in the presence of propan-2-ol, butan-2-ol and toluene

    Science.gov (United States)

    McCausland, Jeffrey A.; Withanage, Sajeevi; Mallik, Robert R.; Lyuksyutov, Sergei F.

    2017-07-01

    A technique, based on amplitude modulation of Atomic Force Microscope (AFM) tips, in the absence of an applied bias voltage, is reported in this study. Under ambient humidity conditions, ultra-sharp n-doped silicon tips (spike radius 1 nm) oscillating at 160-250 kHz generate raised nanostructures 50-200 nm wide and 2 nm high on undoped or p-doped Si (100) surfaces pretreated with certain neat organic solvents. The solvents in the present work are propan-2-ol, butan-2-ol, or toluene. AFM is used to characterize the nanostructures which are found to be stable for at least 96 h. It is suggested that mechanical stress associated with the oscillatory Hookean energy ( 5-15 eV) of the tip promotes cleavage of residual solvent bonds on the surface. This bond cleavage, and the presence of surface defects, which may be critical in the formation of surface-solvent bonds (specifically Si-O-C or Si-C) to create the observed nanostructures, is discussed. The process described here to create raised nanostructures is distinctly different from all other reported techniques to date.

  11. Lorentz microscopy observation of vortices in high-Tc superconductors using a 1-MV field emission transmission electron microscope.

    Science.gov (United States)

    Harada, Ken

    2013-06-01

    Lorentz microscopy has opened the door to observing a single quantized magnetic flux line (i.e. a vortex) and its dynamic behavior inside a superconductor in real time. It resulted from the efforts of Dr Akira Tonomura and his collaborators, who developed a field emission electron microscope and advanced the technologies used for visualizing vortices (e.g. a low-temperature specimen stage and a magnetic-field application system). They used a 1-MV field emission transmission electron microscope with an electron beam that can penetrate thick specimens of high-temperature superconductors (Bi2Sr2CaCu2O8+δ and YB2C3O7-δ) to reveal the flux-line features inside materials and their interactions with defects. This memorial paper reviews the results of research in the area of vortex matter physics.

  12. Scanning electron microscopic observations of the development of the chicken caecum.

    Science.gov (United States)

    Sabatakou, O; Paraskevakou, E; Tseleni-Balafouta, S; Athanasiadis, A; Fasseas, C

    2003-10-01

    The surface pattern of the caeca of the chicken was examined using the scanning electron microscope (SEM) in stages ranging from 11th day of foetal development to 60 days of post-natal life. During incubation the proximal region (basis) of the caecum presented a few irregular elevations, which were later regarded as villi and after hatching, gradually, became longer and wider. These structures were found to be similar to those of the small intestine. The middle (corpus) and distal (apex) regions of caecum presented ridges/folds with short and blunt villi that were even shorter in the apex. The ridges/folds were running longitudinally the inner surface of the corpus while those of the apex were not so well developed.

  13. Dynamics of Supported Metal Nanoparticles Observed in a CS Corrected Environmental Transmission Electron Microscope

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Dunin-Borkowski, Rafal E.; Wagner, Jakob Birkedal

    of the support were deposited onto an amorphous carbon film on a 3mm copper TEM grid and sputter coated with a thin film of gold. The Au film readily formed nanoparticles ranging from a few nm up to 20nm in size. The samples were exposed to oxidizing and reducing environments at various temperatures......In catalyst design, high performance and stability are key issues. Many catalysts consist of metals or metal alloys deposited onto a support material as nanoparticles in order to optimize the exposed surface area. When exposed to the environment in a catalytic reactor, the particles tend to sinter...... of the microscope is needed. As industrial catalysts are usually complex high surface area materials, they are often not suited for fundamental studies. For this purpose, model systems consisting of gold nanoparticles on sheets of low surface area boron nitride and graphite supports were produced. Sheets...

  14. SEM and stereoscope microscope observations on the seeds of the Polish species of the genus Sorbus L. (Rosaceae

    Directory of Open Access Journals (Sweden)

    Irmina Maciejewska-Rutkowska

    2011-01-01

    Full Text Available This paper presents the results of the study on seed morphology of five Polish species of the genus Sorbus L. (S. aria (L. Crantz, S. aucuparia L. Emend. Hedl., S. chamaemespilus (L. Crantz, S. intermedia (Ehrh. Pers. and S. torminalis (L. Crantz. Observations and measurements were carried out with stereoscope and scanning microscopes. Four types of seed microsculpture were distinguished on the ground of SEM observations. The key to determine Polish species, based on morphological characters of seeds is given too.

  15. High-voltage electron-microscopic observation of cyclic slip behavior around a fatigue crack tip in an iron alloy

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Yoshimasa [National Institute of Advanced Industrial Science and Technology (AIST), 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)], E-mail: yoshim.takahashi@aist.go.jp; Tanaka, Masaki; Higashida, Kenji [Department of Materials Science and Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Noguchi, Hiroshi [Department of Mechanical Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2009-04-15

    The cyclic slip behavior around a fatigue crack tip originally located inside a bulk Fe-Si alloy was successfully observed by a high-voltage electron microscope in combination with a novel specimen preparation method. The method, by taking advantages of ion milling and focused ion beam techniques, ensures that the original shape of the crack tip is preserved without introducing additional slips. The observation confirms that the slip bands emitted from the fatigue crack tip are bounded by a labyrinth-like wall structure.

  16. Observation of Amorphous Recording Marks Using Reflection-Mode Near-Field Scanning Optical Microscope Supported by Optical Interference Method

    Science.gov (United States)

    Sakai, Masaru; Mononobe, Shuji; Yusu, Keiichiro; Tadokoro, Toshiyasu; Saiki, Toshiharu

    2005-09-01

    A signal enhancing technique for a reflection-mode near-field scanning optical microscope (NSOM) is proposed. Optical interference between the signal light, from an aperture at the tip of a tapered optical fiber, and the reflected light, from a metallic coating around the aperture, enhances the signal intensity. We used a rewritable high-definition digital versatile disc (HD DVD) with dual recording layers as a sample medium, and demonstrated observation of amorphous recording marks on the semitransparent (the first) recording layer. In spite of low optical contrast between the crystal region and the amorphous region on this layer, we successfully observed recording marks with good contrast.

  17. Wide-range length metrology by dual-imaging-unit atomic force microscope based on porous alumina.

    Science.gov (United States)

    Zhang, Dongxian; Zhang, Haijun; Lin, Xiaofeng

    2004-06-15

    A new dual-imaging-unit atomic force microscope (DIU-AFM) was developed for wide-range length metrology. In the DIU-AFM, two AFM units were combined, one as a reference unit, and the other a test one. Their probes with Z piezo elements and tips were horizontally set in parallel at the same height to reduce errors due to geometric asymmetry. An XY scanner was attached to an XY block that was able to move in the X direction with a step of about 500 nm. A standard porous alumina film was employed as the reference sample. Both reference sample and test sample were installed at the center of the XY scanner on the same surface and were simultaneously imaged. The two images had the same lateral size, and thus the length of the test sample image could be accurately measured by counting the number of periodic features of the reference one. The XY block together with the XY scanner were next moved in the X direction for about 1.5 microm and a second pair of reference and test images were obtained by activating the scanner. In this way, a series of pairs of images were acquired and could be spliced into two wide-range reference and test images, respectively. Again, the two spliced images were of the same size and the length of test image was measured based on the reference one. This article presents a discussion about the structure and control of the DIU-AFM system. Some experiments were carried out on the system to demonstrate the method of length calculation and measurement. Experiments show a satisfactory result of wide-range length metrology based on the hexagonal features of the porous alumina with a periodic length of several tens of nanometers. Using this method the DIU-AFM is capable of realizing nanometer-order accuracy length metrology when covering a wide range from micron to several hundreds of microns, or even up to millimeter order.

  18. Research on a Diamond Tip Wear Mechanism in Atomic Force Microscope-based Micro/nano-machining

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The object is to investigate the wear of an atomic forcemicroscope (AFM) diamond tip when conducting micro/nano-machining on single crystal silicon surface. The experimental research and theoretical analysis were carried out on the worn tip in terms of wear rate, wear mechanism and the effect of the tip wear on micro-machining process. The wear rate was calculated as 1.7(10~10mm3/(N*m) by using a theoretical model combined with the experimental results. Through an integration of an AFM observation on the worn tip features with the FEM simulation of the stress distribution, in addition to the unit cutting force calculation on the AFM diamond tip, the wear mechanism of the AFM diamond tip was concluded as mainly chemical wear, and the wear process was also elaborated as well.

  19. Multiparameter breast cancer cell image analysis for objective estimation of nuclear grade: comparison with light microscopic observational data

    Science.gov (United States)

    Berzins, Juris; Sneiders, Uldis; Plegere, Daina; Freivalds, Talivaldis; Grigalinovica, Romalda

    2000-04-01

    We performed a multi parameter image analysis assessment of breast cancer cell population nuclear grade (NG), which is regarded as one of the main prognostic factors for treatment efficacy and survival of the patients and compared it with light microscopic estimation of NG. Cytological imprint slides from 20 ductal carcinomas were stained according to Leischmann-AzureII-eosine method, and NG was estimated by light microscopic observation according to Black in Fisher's modification. Simultaneously, using specially elaborated software, in each patient 100 cancer cells were analyzed for nuclear perimeter, diameter, area, nucleolar area, and average intensity of staining. The chromatin structure was assessed using mean diameter of chromatin grains and relatively chromatic are within the nucleus. Light microscopic estimation revealed 4/15 grade 2 and 7/15 grade 3 tumors out of 15 filtrating ductal carcinomas, with 4/15 classified as intermediate between grade 2-3. Multifactoral linear correlation coefficient r equals 0.39, p < 0.001 for ductal cancer, higher NG comes with increasing nucleolar area, nuclear roundness factor, nuclear are, and chromatin area within the cell nucleus. Image analysis may yield precise information on NG as a prognostic factor in breast cancer patients.

  20. Observation of the Kibble-Zurek Mechanism in Microscopic Acoustic Crackling Noises

    Science.gov (United States)

    Ghaffari, H. O.; Griffth, W. A.; Benson, P. M.; Xia, K.; Young, R. P.

    2016-02-01

    Characterizing the fast evolution of microstructural defects is key to understanding “crackling” phenomena during the deformation of solid materials. For example, it has been proposed using atomistic simulations of crack propagation in elastic materials that the formation of a nonlinear hyperelastic or plastic zone around moving crack tips controls crack velocity. To date, progress in understanding the physics of this critical zone has been limited due to the lack of data describing the complex physical processes that operate near microscopic crack tips. We show, by analyzing many acoustic emission events during rock deformation experiments, that the signature of this nonlinear zone maps directly to crackling noises. In particular, we characterize a weakening zone that forms near the moving crack tips using functional networks, and we determine the scaling law between the formation of damages (defects) and the traversal rate across the critical point of transition. Moreover, we show that the correlation length near the transition remains effectively frozen. This is the main underlying hypothesis behind the Kibble-Zurek mechanism (KZM) and the obtained power-law scaling verifies the main prediction of KZM.

  1. Cell Aging of Mouse Gastrointestinal Tract Observed by Light and Electron Microscopic Radioautography

    Science.gov (United States)

    Nagata, Tetsuji

    2014-01-01

    The term “cell aging” initially means how the cells change due to their aging. There are two meanings, i.e. how a cell changes when it is isolated from original animals such as in vitro cells in cell culture, otherwise how all the cells of an animal change in vivo due to the aging of the individual animal. We have been studying the latter changes from the viewpoint of the cell nutrients, the precursors for the macromolecular synthesis such as deoxyribonucleic acid (DNA), ribonucleic acid (RNA), proteins, glucides and lipids, which are incorporated and synthesized into various cells of individual animals. Therefore, this article deals with only the cell aging of animal cells in vivo, how the metabolism, i.e. incorporations and syntheses of respective nutrient precursors in various kinds of cells change due to the aging of individual experimental animals such as mice by means of microscopic radioautography to localize the RI-labeled precursors. The incorporations and syntheses of various precursors for macromolecules such as DNA, RNA, proteins, glucides, lipids and others in various kinds of cells of various organs in the gastrointestinal tract such as the mouth, esophagus, stomach and intestines are reviewed referring many original papers already published from our laboratory during these 60 years since the late 20th century. PMID:27785275

  2. Parameters affecting the adhesion strength between a living cell and a colloid probe when measured by the atomic force microscope.

    Science.gov (United States)

    McNamee, Cathy E; Pyo, Nayoung; Tanaka, Saaya; Vakarelski, Ivan U; Kanda, Yoichi; Higashitani, Ko

    2006-03-15

    In this study, we used the colloid probe atomic force microscopy (AFM) technique to investigate the adhesion force between a living cell and a silica colloid particle in a Leibovitz's L-15 medium (L-15). The L-15 liquid maintained the pharmaceutical conditions necessary to keep the cells alive in the outside environment during the AFM experiment. The force curves in such a system showed a steric repulsion in the compression force curve, due to the compression of the cells by the colloid probe, and an adhesion force in the decompression force curve, due to binding events between the cell and the probe. We also investigated for the first time how the position on the cell surface, the strength of the pushing force, and the residence time of the probe at the cell surface individually affected the adhesion force between a living cell and a 6.84 microm diameter silica colloid particle in L-15. The position of measuring the force on the cell surface was seen not to affect the value of the maximum adhesion force. The loading force was also seen not to notably affect the value of the maximum adhesion force, if it was small enough not to pierce and damage the cell. The residence time of the probe at the cell surface, however, clearly affected the adhesion force, where a longer residence time gave a larger maximum force. From these results, we could conclude that the AFM force measurements should be made using a loading force small enough not to damage the cell and a fixed residence time, when comparing results of different systems.

  3. Collective behaviour in two-dimensional cobalt nanoparticle assemblies observed by magnetic force microscopy.

    Science.gov (United States)

    Puntes, Victor F; Gorostiza, Pau; Aruguete, Deborah M; Bastus, Neus G; Alivisatos, A Paul

    2004-04-01

    The use of magnetic nanoparticles in the development of ultra-high-density recording media is the subject of intense research. Much of the attention of this research is devoted to the stability of magnetic moments, often neglecting the influence of dipolar interactions. Here, we explore the magnetic microstructure of different assemblies of monodisperse cobalt single-domain nanoparticles by magnetic force microscopy and magnetometric measurements. We observe that when the density of particles per unit area is higher than a determined threshold, the two-dimensional self-assemblies behave as a continuous ferromagnetic thin film. Correlated areas (similar to domains) of parallel magnetization roughly ten particles in diameter appear. As this magnetic percolation is mediated by dipolar interactions, the magnetic microstructure, its distribution and stability, is strongly dependent on the topological distribution of the dipoles. Thus, the magnetic structures of three-dimensional assemblies are magnetically soft, and an evolution of the magnetic microstructure is observed with consecutive scans of the microscope tip.

  4. The micromorphology of the blesbuck louse Damalinia (Damalinia crenelata as observed under the scanning electron microscope

    Directory of Open Access Journals (Sweden)

    M.L. Turner

    2003-12-01

    Full Text Available The blesbuck is an important game animal on many game farms and reserves in South Africa. Damalinia crenelata, a biting louse, host-specific to the blesbuck, feed upon epidermal debris of this antelope, leading to severe skin irritation and dermatitis. Symptomatic scratching by the host aggravates these conditions. High infestations may lead to decreased population numbers. Live lice were collected from a blesbuck in the Rietvlei Nature Reserve and prepared for selectron microscopic investigation. Micrographs were recorded. The SEM investigation revealed several micromorphological features not previously described in D. crenelata. Besides the obvious anatomical differences in the reproductive organs of the male and female, several other differences were noted. The antennal flagellae showed morphological differences as well as certain features on the ventral surfaces of the head. Dorsally the forehead was markedly emarginated and showed an acute invagination (clypeo labral suture in the pulvinal area. The ventral surface of the head clearly demonstrated the structures of the preantennal regions such as ventral carina, pulvinus, labrum, mandibles and clypeus. The epipharynx appeared as an underlying extension of the labrum. The rims of the clypeus were more raised and thickened in the female than in that of the male. The mandibles were not notched and were noted to be angular in shape. The three segments of each of the antennae of the male were thicker and more robust than than those of the female. This could suggest sexual dimorphism in this species. The sensilla basoconica comprised 10 pegs. Pit organs were seen within the pore organs. The prothorax and mesothorax were clearly distinguished. The abdominal segments showed six pairs of spiracles. The male andfemale terminalia were confirmed to be strongly sexually dimorphic. The three pairs oflegs each terminated in a single, long and slender, claw.

  5. Observation of dendritic growth under the influence of forced convection

    Science.gov (United States)

    Roshchupkina, O.; Shevchenko, N.; Eckert, S.

    2015-06-01

    The directional solidification of Ga-25wt%In alloys within a Hele-Shaw cell was visualized by X-ray radioscopy. The investigations are focused on the impact of melt convection on the dendritic growth. Natural convection occurs during a bottom up solidification because lighter solute is rejected during crystallization. Forced convection was produced by a specific electromagnetic pump. The direction of forced melt flow is almost horizontal at the solidification front. Melt flow induces various effects on grain morphology primarily caused by convective transport of solute, such as a facilitation of the growth of primary trunks or lateral branches, dendrite remelting, fragmentation or freckle formation depending on the dendrite orientation, the flow direction and intensity. Forced flow eliminates solutal plumes and damps local fluctuations of solute. A preferential growth of the secondary arms occurs at the upstream side of the dendrites, whereas high solute concentration at the downstream side inhibits the formation of secondary branches.

  6. Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth

    Directory of Open Access Journals (Sweden)

    B Pratebha

    2014-01-01

    Results: The CDJ appeared to be a fibril poor groove with a width of 2-4 µm. Few areas of collagen fiber intermingling could be appreciated. A detailed observation of these tissues has been presented.

  7. High-voltage electron-microscopical observation of crack-tip dislocations in silicon crystals

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Masaki [Department of Materials Science and Engineering, Kyushu University, 6-10-1 Higashi-ku Fukuoka 812-8581 (Japan)]. E-mail: masaki@dera.zaiko.kyushu-u.ac.jp; Higashida, Kenji [Department of Materials Science and Engineering, Kyushu University, 6-10-1 Higashi-ku Fukuoka 812-8581 (Japan)

    2005-07-25

    Crack-tip dislocations in silicon single crystals were observed by high-voltage electron microscopy. Cracks were introduced into silicon wafers at room temperature by a Vickers indenter. The indented specimens were annealed at 823 K in order to activate dislocation emission from the crack tip under the residual stress due to the indentation. In the specimen without annealing, no dislocations were observed around the crack. On the other hand, in the specimen after the annealing, the aspect of the early stage of dislocation emission was observed, where dislocations were emitted not as a perfect dislocation but as a partial dislocation in the hinge-type plastic zone. Prominent dislocation arrays that were emitted from a crack tip were also observed, and they were found to be of shielding type, which increases the fracture toughness of those crystals.

  8. Direct observation of photoinduced charge redistribution of WO3-TiO2 double layer nanocomposite films by photoassisted Kelvin force microscopy

    Science.gov (United States)

    Wang, S. J.; Cheng, G.; Jiang, X. H.; Li, Y. C.; Huang, Y. B.; Du, Z. L.

    2006-05-01

    The microscopic photoinduced charge redistribution between heterogeneous semiconductor nanofilms of WO3 and TiO2 double layers (written as WO3-TiO2 nanocomposite films) was directly observed using Kelvin probe force microscopy (KFM) coupled with an UV light source. Under illumination the surface potential morphologies of WO3-TiO2 nanocomposite films changed from 162to592mV, which was associated with the photoinduced charge transfer between WO3 and TiO2 nanoparticles due to the energy level alignment between them. This improved technique of photoassisted KFM was presented to visualize the photoinduced charge transfer between different semiconductor nanoparticles on microscopic scale.

  9. Estimation of the radial force using a disturbance force observer for a magnetically levitated centrifugal blood pump.

    Science.gov (United States)

    Pai, C N; Shinshi, T; Shimokohbe, A

    2010-01-01

    Evaluation of the hydraulic forces in a magnetically levitated (maglev) centrifugal blood pump is important from the point of view of the magnetic bearing design. Direct measurement is difficult due to the absence of a rotor shaft, and computational fluid dynamic analysis demands considerable computational resource and time. To solve this problem, disturbance force observers were developed, using the radial controlled magnetic bearing of a centrifugal blood pump, to estimate the radial forces on the maglev impeller. In order to design the disturbance observer, the radial dynamic characteristics of a maglev impeller were evaluated under different working conditions. It was observed that the working fluid affects the additional mass and damping, while the rotational speed affects the damping and stiffness of the maglev system. Based on these results, disturbance force observers were designed and implemented. The designed disturbance force observers present a bandwidth of 45 Hz. In non-pulsatile conditions, the magnitude of the estimated radial thrust increases in proportion to the flowrate, and the rotational speed has little effect on the force direction. At 5 l/min against 100 mmHg, the estimated radial thrust is 0.95 N. In pulsatile conditions, this method was capable of estimating the pulsatile radial thrust with good response.

  10. Microscopic Observation of the Light-Cone-Like Thermal Correlations in Cracking Excitations

    CERN Document Server

    Ghaffari, H O

    2016-01-01

    Many seemingly intractable systems can be reduced to a system of interacting spins. Here, we introduce a system of artificial acoustic spins which are manipulated with ultrasound excitations associated with micro-cracking sources in thin sheets of crystals. Our spin-like system shows a peculiar relaxation mechanism after inducing an impulsive stress-ramp akin to splitting, or rupturing, of the system. Using real-time construction of correlations between spins states, we observe a clear emergence of the light cone effect. It has been proposed that equilibration horizon occurs on a local scale in systems where correlations between distant sites are established at a finite speed. The observed equilibration horizon in our observations defines a region where elements of the material are in elastic communication through excited elementary excitations. These results yield important insights into dynamic communication between failing elements in brittle materials during processes such as brittle fragmentation and dyn...

  11. Electron microscopic observation and rotational diffusion measurement of bacteriorhodopsin in lipid vesicles

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The morphology of bacteriorhodopsin reconstituted into dimyristoylphosphatidylcholine and egg-phosphatidylcholine vesicles was observed by freeze-fracture electron microscopy. The rotational diffusion of bacteriorhodopsin at different concentrations of melittin was measured by observing flash-induced transient dichroism in dimyristoylphosphatidylcholine vesicles. In the presence of melittin, bacteriorhodopsin molecules in dimyristoylphosphatidylcholine vesicles were aggregated into large particles or patches, and the ability of rotational diffusion of bacteriorhodop sin in vesicles was decreased. This suggests that melittin produces its effect via direct electrostatic interaction with bacteriorhodopsin. Low temperature-induced aggregation of bacteriorhodopsin was also observed in dimyristoylphosphatidylcholine vesicles. Low temperature may cause phase separation. Bacteriorhodopsin was also successfully reconstituted into egg-phosphatidylcholine vesicles, but Iow temperature-induced aggregation of bacteriorhodopsin in dimyristoylphosphati dylcholine cannot appear in egg-phosphatidylcholine vesicles. This suggests that different lipids have different effects on bacteriorhodopsin in vesicles.

  12. Field Observations of Bioaerosols: What We've Learned from Fluorescence, Genetic, and Microscopic Techniques (Invited)

    Science.gov (United States)

    Huffman, J. A.; Fröhlich-Nowoisky, J.; Després, V. R.; Elbert, W.; Sinha, B.; Andreae, M. O.; Pöschl, U.

    2009-12-01

    Biogenic aerosols are ubiquitous in the Earth’s atmosphere, influencing atmospheric chemistry and physics, the biosphere, climate, and public health. They play an important role in the spread of biological organisms, and they can cause or enhance human, animal, and plant diseases. Moreover, they can initiate the formation of clouds and precipitation as cloud condensation and ice nuclei (CCN, IN). Primary biogenic aerosol particles (PBAP) such as pollen, fungal spores, and bacteria are emitted directly from the biosphere to the atmosphere. Microscopic investigations have shown that PBAP account for up to ~30% of fine and up to ~70% of coarse particulate matter in rural and rain forest air, and the estimates of PBA emissions range from ~60 Tg a-1 of fine particles up to ~1000 Tg a-1 of total particulate matter. Fungal spores account for a large proportion of PBA with typical number and mass concentrations of ~104 m-3 and ~1 μg m-3 in continental boundary layer air and estimated global emissions of the order of ~50 Tg a-1 and 200 m-2 s-1, respectively [1]. The actual abundance, variability and diversity of PBAP are still poorly understood and quantified, however. By measuring fluorescence at excitation and emission wavelengths specific to viable cells, online techniques with time resolution of minutes are able to detect fluorescent biological aerosol particles (FBAP), which represent a lower limit for the actual abundance of coarse (> 1 μm) PBAP [2]. Continuous sampling (1 - 4 months) was performed at various locations including pristine rain forest, rural and polluted urban sites. Each study exhibited a similar average particle number distribution dominated by a peak at ~3 μm, with coarse FBAP concentrations of the order of ~5x104 m-3 and ~1 μg m-3. Recent advances in the DNA analysis and molecular genetic characterization of aerosol filter samples yield new information about the sources and composition of PBA and provide new insight into regional and global

  13. Atomic force microscopic study of aggregation of RecA-DNA nucleoprotein filaments into left-handed supercoiled bundles.

    Science.gov (United States)

    Shi, Wei-Xian; Larson, Ronald G

    2005-12-01

    RecA and its complexes with double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) are responsible for homologous recombination and DNA repair. In this study, we have observed, by atomic force microscopy (AFM), two-filament left-handed superhelices of RecA-dsDNA filaments that further interwind into four- or six-filament bundles, in addition to previously reported left-handed bundles of three or six filaments. Also revealed are four-filament bundles formed by further interwinding of two intrafilament superhelices of individual filaments. Pitches of superhelices of RecA-DNA filaments are similar to each other regardless the number of component filaments, and those formed on Phix174 RFII dsDNA and pNEB206A dsDNA are measured as 339.3 +/- 6.2 nm (690 counts of pitch/2) and 321.6 +/- 11.7 nm (101 counts of pitch/2), respectively, consistent with earlier measurements made by electron microscopy with a much smaller sample size. The study of these structures provides insight into the self-interactions of RecA and RecA-like proteins, which are present in all living cells, and into the general phenomenon of bundling, which is relevant to both biological and nonbiological filaments.

  14. Atomic force microscopic view of the fine topography on the tobacco stigma surface during its response to pollination

    Institute of Scientific and Technical Information of China (English)

    WU Hui; LI Meng; SUN MengXiang

    2008-01-01

    During compatible pollination in tobacco, an extracellular matrix (ECM) is secreted from the stigma surface; however, it is unknown whether the pattern of secretion across the stigma depends on the pollen source. In fact, technical limitations have prevented clear observation of ECM secretion. Here, we report the detailed topographic changes on the stigma surface that accompanies intraspecies and interspecies pollination in tobacco using contact mode atomic force microscopy (AFM). Our results, which show the dynamics and time course of ECM secretion after pollination, indicate that a certain pattern of secretion already exists on the stigma prior to pollination. Intraspecies induced a two-step response, characterized by topograPhical changes on the stigma surface several hours after pollina-tion, which was distinct from the pattern of ECM secretion induced by interspecies pollination. This difference was confirmed by root-mean-square analysis, which assessed the roughness of the stigma surface. Our findings indicate that compatible pollination not only induces ECM secretion from the stigma, but also results in a specific distribution of the ECM. Thus, this study demonstrates the pow-erful potential of AFM in studying the pollen-stigma interaction.

  15. An atomic force microscopic investigation of surface degradation of potassium hydrogen phthalate (KAP) crystals caused by removal from solution

    Science.gov (United States)

    Ester, G. R.; Price, R.; Halfpenny, P. J.

    1997-12-01

    Atomic force microscopy (AFM) has been used to examine the nature and extent of surface degradation of the {0 1 0} faces of potassium hydrogen phthalate (KAP) crystals removed from aqueous solution. Crystals separated from their growth solutions by passage through a layer of n-hexane or using a jet of n-hexane exhibited clearly preserved growth spirals. The step terraces, however, were found to be extensively pitted, typically to a depth of approximately 1.4 nm which corresponds to one lattice spacing in the b-direction. In addition to such nanoscale pitting, larger pits several microns in lateral dimensions were also observed. These were frequently hexagonal in shape usually with a shallow mound within or adjacent to the pit. More rapid removal of solution from crystal surfaces was effected using a pulse of compressed air or argon. Under optimised conditions this approach yielded much better surface protection with step terraces in this case being essentially smooth. Step heights on the spirals shown were found to be 1.4 ± 0.2 nm and thus of single unit cell height. The occurrence of pits on the terraces is attributed to deposition of KAP by two dimensional nucleation on the terraces, producing partial coverage and thus the apparently pitted surface.

  16. Microscopic observation of carrier-transport dynamics in quantum-structure solar cells using a time-of-flight technique

    Energy Technology Data Exchange (ETDEWEB)

    Toprasertpong, Kasidit; Fujii, Hiromasa; Sugiyama, Masakazu; Nakano, Yoshiaki [School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032 (Japan); Kasamatsu, Naofumi; Kada, Tomoyuki; Asahi, Shigeo; Kita, Takashi [Graduate School of Engineering, Kobe University, Nada-ku, Kobe 657-8501 (Japan); Wang, Yunpeng; Watanabe, Kentaroh [Research Center for Advanced Science and Technology, The University of Tokyo, Meguro-ku, Tokyo 153-8904 (Japan)

    2015-07-27

    In this study, we propose a carrier time-of-flight technique to evaluate the carrier transport time across a quantum structure in an active region of solar cells. By observing the time-resolved photoluminescence signal with a quantum-well probe inserted under the quantum structure at forward bias, the carrier transport time can be efficiently determined at room temperature. The averaged drift velocity shows linear dependence on the internal field, allowing us to estimate the quantum structure as a quasi-bulk material with low effective mobility containing the information of carrier dynamics. We show that this direct and real-time observation is more sensitive to carrier transport than other conventional techniques, providing better insights into microscopic carrier transport dynamics to overcome a device design difficulty.

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

    Directory of Open Access Journals (Sweden)

    E. Kevin Tanyi

    2014-12-01

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

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

    Science.gov (United States)

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

    2009-09-01

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

  19. Microscopic Polyangiitis

    Science.gov (United States)

    ... are here: Home / Types of Vasculitis / Microscopic Polyangiitis Microscopic Polyangiitis First Description Who gets Microscopic Polyangiitis (the “ ... differences as to justify separate classifications. Who gets Microscopic Polyangiitis? A typical patient MPA can affect individuals ...

  20. Synthesis of Fluorescent Gelators and Direct Observation of Gelation with a Fluorescence Microscope.

    Science.gov (United States)

    Hanabusa, Kenji; Ueda, Takuya; Takata, Shingo; Suzuki, Masahiro

    2016-11-14

    Fluorescein-, benzothiazole-, quinoline-, stilbene-, and carbazole-containing fluorescent gelators have been synthesized by connecting gelation-driving segments, including l-isoleucine, l-valine, l-phenylalanine, l-leucine residue, cyclo(l-asparaginyl-l-phenylalanyl), and trans-(1R,2R)-diaminocyclohexane. The emission behaviors of the gelators were investigated, and their gelation abilities studied against 15 solvents. The minimum gel concentration, variable-temperature spectroscopy, transmission electron microscopy, scanning electron microscopy, fluorescence microscopy (FM), and confocal laser scanning microscopy (CLSM) were used to characterize gelation. The intermolecular hydrogen bonding between the N-H and C=O of amide, van der Waals interactions and π-π stacking play important roles in gelation. The colors of emission are related to the fluorescence structures of gelators. Fibrous aggregates characterized by the color of their emission were observed by FM. 3D images are produced by the superposition of images captured by CLSM every 0.1 μm to a settled depth. The 3D images show that the large micrometer-sized aggregates spread out three dimensionally. FM observations of mixed gelators are studied. In the case of gelation, two structurally related gelators with the same gelation-driving segment lead to the gelators build up of the same aggregates through similar hydrogen-bonding patterns. When two gelators with structurally different gelation-driving segments induce gelation, the gelators build up each aggregate through individual hydrogen-bonding patterns. A fluorescent reagent that was incorporated into the aggregates of gels through van der Waals interactions was developed. The addition of this fluorescent reagent enables the successful observation of nonfluorescent gelators' aggregates by FM.

  1. Acinic cell carcinoma arising in the glossopalatine glands: a report of two cases with electron microscopic observations.

    Science.gov (United States)

    Inoue, T; Shimono, M; Yamamura, T; Saito, I; Watanabe, O; Kawahara, H

    1984-04-01

    Two cases of acinic cell carcinoma arising in the glossopalatine glands were examined with the electron microscope by means of conventional thin sectioning and freeze-fracturing. Light and electron microscopic observation revealed that the tumors consisted of three types of cells: serous-type, ductlike, and vacuolated cells. Serous-type cells had numerous secretory granules, some of which were discharged into the intercellular spaces. Ductlike cells were smaller, usually lacked secretory granules, and were similar to intercalated duct cells. Vacuolated cells had electron-opaque vacuoles in the cytoplasm. Our findings supported the hypothesis that acinic cell carcinoma may represent a neoplasm of multipotential duct cells which have differentiated mainly into granulated serous cells. Freeze-fracture images of this tumor revealed that tight junctions were composed of ten or more interlinked strands with elongation of basal frontier strands. These findings suggested that the junctional morphology of the tumor resembled that of developing salivary glands and was associated with the degree of cellular differentiation.

  2. Measurement of microscopic coupling constants between atoms on a surface: Combination of LEEM observation with lattice model analysis

    Science.gov (United States)

    Akutsu, Noriko

    2014-12-01

    We present a method combining low-energy electron microscopy (LEEM) and lattice model analysis for measuring the microscopic lateral coupling constants between atoms on a surface. The calculated step (interface) stiffness in a honeycomb lattice Ising model with the nearest neighbor and the second nearest neighbor interactions (J1 = 93.8 meV and J2 = 9.38 meV) matched the experimental step quantity values on an Si(111)(1 × 1) surface reported by Pang et al. and Bartelt et al. based on LEEM measurements. The experimental value of step tension obtained by Williams et al. lies on the calculated step tension curve. The polar graphs of the step tension and a two-dimensional island shape at the temperature T = 1163 K also agree well with the experimental graphs reported by Métois and Müller. The close agreement between the LEEM observations and the lattice model calculations on a Si(111) surface suggests that our method is also suitable for measuring microscopic lateral coupling constants on the surface of other materials that are less well-studied than Si.

  3. Further observations on the relationship of EMG and muscle force

    Science.gov (United States)

    Agarwal, G. C.; Cecchini, L. R.; Gottlieb, G. L.

    1972-01-01

    Human skeletal muscle may be regarded as an electro-mechanical transducer. Its physiological input is a neural signal originating at the alpha motoneurons in the spinal cord and its output is force and muscle contraction, these both being dependent on the external load. Some experimental data taken during voluntary efforts around the ankle joint and by direct electrical stimulation of the nerve are described. Some of these experiments are simulated by an analog model, the input of which is recorded physiological soleus muscle EMG. The output is simulated foot torque. Limitations of a linear model and effect of some nonlinearities are discussed.

  4. 原子力显微镜在生命科学中的应用%The application of atomic force microscope in life science

    Institute of Scientific and Technical Information of China (English)

    曾洁铭; 曾耀英; 蔡继业; 肇静娴

    2001-01-01

    During the past few years, atomic force microscope (AFM) isbecoming a powerful tool in life science research. With their high-resolution and capability to image under aqueous solution, AFM is applied to investigate the structure of biomolecules and biological process in real time. From visualization of DNA and IgG to DNA transcription, the advances in sample preparation methods have made these events come true. In addition, AFM can be used in molecular recognition. This article illustrates these major achievements of AFM in biological studies.

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

    Science.gov (United States)

    Korayem, Moharam Habibnejad; Nahavandi, Amir

    2017-01-01

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

  6. Correlation of embryonic skeletal muscle myotube physical characteristics with contractile force generation on an atomic force microscope-based bio-microelectromechanical systems device

    Science.gov (United States)

    Pirozzi, K. L.; Long, C. J.; McAleer, C. W.; Smith, A. S. T.; Hickman, J. J.

    2013-08-01

    Rigorous analysis of muscle function in in vitro systems is needed for both acute and chronic biomedical applications. Forces generated by skeletal myotubes on bio-microelectromechanical cantilevers were calculated using a modified version of Stoney's thin-film equation and finite element analysis (FEA), then analyzed for regression to physical parameters. The Stoney's equation results closely matched the more intensive FEA and the force correlated to cross-sectional area (CSA). Normalizing force to measured CSA significantly improved the statistical sensitivity and now allows for close comparison of in vitro data to in vivo measurements for applications in exercise physiology, robotics, and modeling neuromuscular diseases.

  7. Scanning electron microscopical observation of an osteoblast/osteoclast co-culture on micropatterned orthopaedic ceramics

    Directory of Open Access Journals (Sweden)

    Mansur Halai

    2014-09-01

    Full Text Available In biomaterial engineering, the surface of an implant can influence cell differentiation, adhesion and affinity towards the implant. On contact with an implant, bone marrow–derived mesenchymal stromal cells demonstrate differentiation towards bone forming osteoblasts, which can improve osteointegration. The process of micropatterning has been shown to improve osteointegration in polymers, but there are few reports surrounding ceramics. The purpose of this study was to establish a co-culture of bone marrow–derived mesenchymal stromal cells with osteoclast progenitor cells and to observe the response to micropatterned zirconia toughened alumina ceramics with 30 µm diameter pits. The aim was to establish whether the pits were specifically bioactive towards osteogenesis or were generally bioactive and would also stimulate osteoclastogenesis that could potentially lead to osteolysis. We demonstrate specific bioactivity of micropatterns towards osteogenesis, with more nodule formation and less osteoclastogenesis compared to planar controls. In addition, we found that that macrophage and osteoclast-like cells did not interact with the pits and formed fewer full-size osteoclast-like cells on the pitted surfaces. This may have a role when designing ceramic orthopaedic implants.

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

    Energy Technology Data Exchange (ETDEWEB)

    Amano, Ken-ichi, E-mail: aman@tohoku-pharm.ac.jp; Takahashi, Ohgi [Faculty of Pharmaceutical Sciences, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558 (Japan); Suzuki, Kazuhiro [Department of Electronic Science and Engineering, Kyoto University, Katsura, Nishikyo, Kyoto 615-8510 (Japan); Fukuma, Takeshi [Bio-AFM Frontier Research Center, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Onishi, Hiroshi [Department of Chemistry, Faculty of Science, Kobe University, Nada-ku, Kobe 657-8501 (Japan)

    2013-12-14

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

  9. Power spectrum analysis with least-squares fitting: Amplitude bias and its elimination, with application to optical tweezers and atomic force microscope cantilevers

    DEFF Research Database (Denmark)

    Nørlykke, Simon F.; Flyvbjerg, Henrik

    2010-01-01

    Optical tweezers and atomic force microscope (AFM) cantilevers are often calibrated by fitting their experimental power spectra of Brownian motion. We demonstrate here that if this is done with typical weighted least-squares methods, the result is a bias of relative size between -2/n and + 1/n....... The fitted value for the characteristic frequency is not affected by this bias. For the AFM then, force measurements are not affected provided an independent length-scale calibration is available. For optical tweezers there is no such luck, since the spring constant is found as the ratio...... of the characteristic frequency and the diffusion coefficient. We give analytical results for the weight-dependent bias for the wide class of systems whose dynamics is described by a linear (integro)differential equation with additive noise, white or colored. Examples are optical tweezers with hydrodynamic self...

  10. In-Situ Observation of Crystallization and Growth in High-Temperature Melts Using the Confocal Laser Microscope

    Science.gov (United States)

    Sohn, Il; Dippenaar, Rian

    2016-08-01

    This review discusses the innovative efforts initiated by Emi and co-workers for in-situ observation of phase transformations at high temperatures for materials. By using the high-temperature confocal laser-scanning microscope (CLSM), a robust database of the phase transformation behavior during heating and cooling of slags, fluxes, and steel can be developed. The rate of solidification and the progression of solid-state phase transformations can be readily investigated under a variety of atmospheric conditions and be correlated with theoretical predictions. The various research efforts following the work of Emi and co-workers have allowed a deeper fundamental understanding of the elusive solidification and phase transformation mechanisms in materials beyond the ambit of steels. This technique continues to evolve in terms of its methodology, application to other materials, and its contribution to technology.

  11. 申克孢子丝菌的扫描电镜观察%Microscopic observation of the Sporothrix schenckii with the scanning electron microscope

    Institute of Scientific and Technical Information of China (English)

    黄怀球; 李文娟; 袁立燕; 张静; 钟毅; 赵静; 张晓辉; 薛汝增; 李美荣; 陈荣章

    2012-01-01

    目的 观察耐伊曲康唑申克孢子丝菌的超微结构特征,为申克孢子丝菌的临床鉴定提供基础资料.方法 使用玻片法培养申克孢子丝菌,处理后在电镜下观察、拍照及测量.结果 孢子丝菌标本图像清晰立体,可见假轴状分生孢子梗,分生孢子通常为孤立、直立生长,圆锥顶端相对,沿着菌丝轴增殖扩散,形成群集的细齿状的分生孢子链,分生孢子链较长,可弯曲.分生孢子为卵形,细长,约2.0 μm×3.5 μm大小,透明,表面不光滑,有不规则凹陷.结论 该方法准确、可靠,可为申克孢子丝菌临床鉴定提供理论依据.%Objective To evaluate the application of using scanning electron microscope in the clinical diagnosis of an itraconazole-resistant Sporothrix schenckii. Methods Sporothrix schenckii was cultivated with microculturing method and the external morphology was analyzed using a scanning electron microscope. Results A clear three-dimensional image can be obtained under the scanning electron microscope, conidia reach out at right angle from the thin menbrane of the hyphae, most of which is isolated and vertical, with the cones stretch opposite to each other. Conidia spread along the hyphae axis, forming clusters of gear-like conidia chains, sometimes appear to be sleeve-shaped, sometimes quincuncial, part of which bend or fracture. Conidia are ovoid, about 2.0μm×3.5 μm the size, transparent, with the surface unsmooth and irregular pits. Conclusion The obtained images can be used in the identification of Sporothrix schenckii.

  12. Observation of allotropic transformations of plutonium with a hot stage microscope; Etude des transformations allotropiques du plutonium au microscopic a platine chauffante

    Energy Technology Data Exchange (ETDEWEB)

    Mars, J.; Spftiet, B. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    A hot stage microscope designed for the examination of plutonium and its alloys is described. This apparatus was used to study the {alpha} {r_reversible} {beta} and {delta} {r_reversible} {epsilon} allotropic transformations of pure or {beta} and {delta} stabilised plutonium. The {alpha} {yields} {beta} transformation is typically a nucleation and growth process. Some particularities caused by the internal stresses due to the volume change during this transformation are examined. The kinetics has been studied as a function of these stresses and a temperature dependent activation energy for nucleation has been deduced. The {beta} {yields} {alpha} transformation presents a memory effect which implies an orientation relationship between the two phases. This fact is probably caused by the stresses created during the {beta} {yields} {alpha} transition. The {beta} {r_reversible} {gamma} and {delta} {r_reversible} {epsilon} transformations are also diffusion governed processes. (authors) [French] On decrit un microscope a platine chauffante permettant l'examen du plutonium et de ses alliages. Cet appareil a servi a l'etude des transformations {alpha} {r_reversible} {gamma} et {delta} {r_reversible} {epsilon} du plutonium pur ou stabilise en phase {beta} et {delta}. La transformation {alpha} {yields} {beta} est une transformation typique par germination et croissance; elle presente des caracteristiques bien particulieres qui sont dues aux contraintes internes qui prennent naissance au changement de volume a la transformation; la cinetique a ete etudiee en fonction de ces contraintes, et on en a deduit une energie d'activation pour la germination variable avec la temperature. La transformation {beta} {yields} {alpha} presente un effet de memoire qui suppose une relation d'orientation entre les deux phases; ce phenomene semble lie comme auparavant aux contraintes creees par le passage {beta} {yields} {alpha}. Les transformations {beta} {r

  13. Time-Lapse Observation of Electrolysis of Copper Sulfate with a Full-Field X-ray Fluorescence Imaging Microscope

    Science.gov (United States)

    Ohigashi, Takuji; Aota, Tatsuya; Watanabe, Norio; Takano, Hidekazu; Yokosuka, Hiroki; Aoki, Sadao

    2008-06-01

    The time-lapse observation of the electrodeposition of copper in copper sulfate solution was performed by imaging X-ray fluorescence from the copper deposition. The X-ray fluorescence was directly imaged with a full-field Wolter mirror microscope, which was constructed at the Photon Factory. Controlling the electric current in the solution from 0 to 71.7 µA, the deposition of copper on a Pt cathode was directly observed by imaging its X-ray fluorescence. One exposure time for obtaining an X-ray fluorescence image was 80 s. Then, it was 17 min later from the beginning of the electrolysis when the X-ray fluorescence image of the electrodeposition is observed for the first time. At this exposure time, the detection limit of the mass of copper was estimated to be 0.60 pg/image, which was calculated using test samples of 1.00×10-3-1.00 mol/l copper sulfate solutions.

  14. A force-level theory of the rheology of entangled rod and chain polymer liquids. I. Tube deformation, microscopic yielding, and the nonlinear elastic limit

    Science.gov (United States)

    Schweizer, Kenneth S.; Sussman, Daniel M.

    2016-12-01

    We employ a first-principles-based, force-level approach to construct the anharmonic tube confinement field for entangled fluids of rigid needles, and also for chains described at the primitive-path (PP) level in two limiting situations where chain stretch is assumed to either be completely equilibrated or unrelaxed. The influence of shear and extensional deformation and polymer orientation is determined in a nonlinear elastic limit where dissipative relaxation processes are intentionally neglected. For needles and PP-level chains, a self-consistent analysis of transverse polymer harmonic dynamical fluctuations predicts that deformation-induced orientation leads to tube weakening or widening. In contrast, for deformed polymers in which chain stretch does not relax, we find tube strengthening or compression. For all three systems, a finite maximum transverse entanglement force localizing the polymers in effective tubes is predicted. The conditions when this entanglement force can be overcome by an externally applied force associated with macroscopic deformation can be crisply defined in the nonlinear elastic limit, and the possibility of a "microscopic absolute yielding" event destroying the tube confinement can be analyzed. For needles and contour-relaxed PP chains, this force imbalance occurs at a stress of order the equilibrium shear modulus and a strain of order unity, corresponding to a mechanically fragile entanglement tube field. However, for unrelaxed stretched chains, tube compression stabilizes transverse polymer confinement, and there appears to be no force imbalance. These results collectively suggest that the crossover from elastic to irreversible viscous response requires chain retraction to initiate disentanglement. We qualitatively discuss comparisons with existing phenomenological models for nonlinear startup shear, step strain, and creep rheology experiments.

  15. Alternative methods for specification of observed forcing in single-column models and cloud system models

    Science.gov (United States)

    Randall, David A.; Cripe, Douglas G.

    1999-10-01

    We discuss alternative methods for prescribing advective tendencies in single-column models (SCMs) and cloud system models. These include "revealed forcing," in which the total advective tendency is prescribed from observations; "horizontal advective forcing," in which the horizontal advective tendencies are prescribed, together with the observed vertical motion which is combined with the predicted sounding to determine the tendencies due to vertical advection; and "relaxation forcing," in which the horizontal advective tendencies are computed by relaxing the sounding toward the observed upstream sounding, with a relaxation timescale determined by the time required for the wind to carry parcels across the grid column. When relaxation forcing is used, the horizontal advective tendencies can be diagnosed from the model output and compared with the corresponding observed tendencies. We present SCM results to illustrate these three forcing methods, based on data from several field experiments in both the tropics and the midlatitudes. Each method is shown to have its strengths and weaknesses. Overall, the results presented here do not show unambiguous differences between revealed forcing and horizontal advective forcing. The two methods appear to be generally comparable. Revealed forcing may therefore be preferred for its simplicity. Relaxation forcing guarantees realistic soundings of the state variables but can produce large errors in parameterized processes which are driven by rates (e.g., fluxes) rather than states. In particular, relaxation forcing gives large errors in the precipitation rate in this model. We demonstrate that relaxation forcing leads to unrealistically high (low) precipitation in versions of the model which tend to produce unrealistically dry (humid) soundings. The observed horizontal advective tendencies in the tropics are so weak, especially for temperature, that small absolute errors in the diabatic tendencies diagnosed with relaxation forcing

  16. Hydration effects on gypsum dissolution revealed by in situ nanoscale atomic force microscopy observations

    Science.gov (United States)

    Burgos-Cara, A.; Putnis, C. V.; Rodriguez-Navarro, C.; Ruiz-Agudo, E.

    2016-04-01

    Recent work has suggested that the rates of mineral dissolution in aqueous solutions are dependent on the kinetics of dehydration of the ions building the crystal. Dehydration kinetics will be ultimately determined by the competition between ion-water and water-water interactions, which can be significantly modified by the presence of background ions in solution. At low ionic strength, the effect of electrolytes on ion-water (electrostatic) interactions will dominate (Kowacz et al., 2007). By performing macroscopic and in situ, microscopic (atomic force microscopy) dissolution experiments, the effect of background electrolytes on the dissolution kinetics of gypsum (CaSO4·2H2O) {0 1 0} cleavage surfaces is tested at constant, low ionic strength (IS = 0.05) and undersaturation (saturation index, SI = -0.045). Dissolution rates are systematically lower in the presence of 1:1 background electrolytes than in an electrolyte-free solution, regardless of the nature of the electrolyte tested. We hypothesize that stabilization of the hydration shell of calcium by the presence of background ions can explain this result, based on the observed correlations in dissolution rates with the ionic surface tension increment of the background ion in solution. Stabilization of the cation hydration shell should favor dissolution. However, in the case of strongly hydrated ions such as Ca2+, this has a direct entropic effect that reduces the overall ΔG of the system, so that dissolution is energetically less favorable. Overall, these results provide new evidence that supports cation dehydration being the rate-controlling step for gypsum dissolution, as proposed for other minerals such as barite, dolomite and calcite.

  17. The Cassie-Wenzel transition of fluids on nanostructured substrates: Macroscopic force balance versus microscopic density-functional theory

    CERN Document Server

    Tretyakov, Nikita; Vollmer, Doris; Butt, Hans-Jürgen; Dünweg, Burkhard; Daoulas, Kostas Ch

    2016-01-01

    Classical density functional theory is applied to investigate the validity of a phenomenological force-balance description of the stability of the Cassie state of liquids on substrates with nanoscale corrugation. A bulk free-energy functional of third order in local density is combined with a square-gradient term, describing the liquid-vapor interface. The bulk free energy is parameterized to reproduce the liquid density and the compressibility of water. The square-gradient term is adjusted to model the width of the water-vapor interface. The substrate is modeled by an external potential, based upon Lennard-Jones interactions. The three-dimensional calculation focuses on substrates patterned with nanostripes and square-shaped nanopillars. Using both the force-balance relation and density-functional theory, we locate the Cassie-to-Wenzel transition as a function of the corrugation parameters. We demonstrate that the force-balance relation gives a qualitatively reasonable description of the transition even on t...

  18. Serum-induced degradation of 3D DNA box origami observed with high-speed atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    Zaixing Jiang[1,2,3; Shuai Zhang[2,3; Chuanxu Yang[2; Jorgen Kjems[2; Yudong Huang[1; Flemming Besenbacher[2; Mingdong Dong[2

    2015-01-01

    3D DNA origami holds tremendous potential for the encapsulation and selective release of therapeutic drugs. Observations of the real-time performance of these structures in physiological environments will contribute to the development of future applications. We investigated the degradation kinetics of 3D DNA box origami in serum by using high-speed atomic force microscope optimized for imaging 3D DNA origami in real time. The time resolution allowed to characterize the stages of serum effects on individual 3D DNA boxes origami with nanometer resolution. Our results indicate that the digestion process is a combination of rapid collapse and slow degradation phases. Damage to box origami occurs mainly in the collapse phase. Thus, the structural stability of 3D DNA box origami should be improved, especially in the collapse phase, before these structures are used in clinical applications.

  19. Spatial dependence of polycrystalline FTO’s conductance analyzed by conductive atomic force microscope (C-AFM)

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, Alexandre Pessoa; Costa, J. C. da [Department of Electrical Engineering, University of Brasília, Campus Universitário Darcy Ribeiro, Asa Norte, PO Box 4386, Brasília - DF, 70919-970 (Brazil)

    2014-05-15

    Fluorine-doped Tin oxide (FTO) is a highly transparent, electrically conductive polycrystalline material frequently used as an electrode in organic solar cells and optical-electronic devices [1–2]. In this work a spatial analysis of the conductive behavior of FTO was carried out by Conductive-mode Atomic Force Microscopy (C-AFM). Rare highly oriented grains sample give us an opportunity to analyze the top portion of polycrystalline FTO and compare with the border one. It is shown that the current flow essentially takes place through the polycrystalline edge at grain boundaries.

  20. Microscopic observation of leukocyte kinesis in the vascular bed during hemodialysis using the rabbit ear chamber technique.

    Science.gov (United States)

    Teraoka, S; Sugawara, M; Kitano, Y; Hoshino, T; Takahashi, M; Minagawa, Y; Naganuma, S; Sanaka, T; Mineshima, M; Era, K

    1989-04-01

    Leukocyte kinesis in the capillary vascular bed during hemodialysis (HD) was investigated to elucidate the mechanism of transient leukopenia. Leukocyte movement was observed microscopically during HD using the rabbit ear chamber (REC) technique, which permits visualization of the movement of blood corpuscles in capillaries. Blood was drawn from the femoral artery and returned into the auricular and/or carotid artery so that the blood passing through the hollow fiber artificial kidney (HFAK) flowed into capillaries in the REC. Leukocyte counts of blood samples taken from the afferent and efferent limbs of the HD circuit, the right jugular vein and the right atrium were determined consecutively during HD. The difference in the leukocyte count was observed between the afferent and efferent limbs for the first 15 minutes and thereafter between the efferent limb and the jugular vein. The "transpulmonary" difference in the leukocyte count was not noticed throughout HD. Between 15 and 90 minutes after the start of HD, scarcely any circulating leukocytes were found in capillaries in the REC and some leukocytes were attached to the endothelial surface. Thereafter circulating leukocytes were seen again and detachment of leukocytes from the endothelial surface was observed. No leukocyte aggregation or embolization of aggregating leukocytes was noticed. This evidence suggests that leukopenia may be attributed to the transient shift of leukocytes to the marginal pool of the vessel lumen and this process may not be specific for the pulmonary vasculature, but may occur in the first capillary bed into which the blood passing through the HFAK flows.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Evaluation of the interactions between polymeric chains and surfaces with different structures performed by an atomic force microscope

    Directory of Open Access Journals (Sweden)

    Oréfice Rodrigo Lambert

    1998-01-01

    Full Text Available Interactions between polymers and inorganic surfaces are present in a series of phenomena involving processes such as coagulation and deffloculation of ceramic powder and adsorption of organic macromolecules on the surface of implants, among others. In this work, Atomic Force Microscopy (AFM was modified to allow the evaluation of interactions between polymeric chains and inorganic surfaces (silica with different structures. Polymers (sulfonated polysulfone were grafted onto AFM cantilevers. AFM force-distance curves were obtained for this modified tip against a series of substrates produced by depositing silica films on silicon wafers. The structure of the silica layer was modified by employing heat treatments at different temperatures. The results showed that the interactions between polymer and surfaces are dependent on the structure of the surfaces. Penetration of the polymeric chains can occur through a soft gel layer (substrates treated at low temperature, 110 °C. For surfaces with dense silica layers, the results showed that not only the concentration of hydroxy groups but also their spatial distribution along the surfaces are important in defining the magnitude of interactions between polymers and surfaces. A model involving a molecular recognition process, in which interactions are maximized for inorganic surfaces with structures that can match the chemical architecture of the polymer, was then used to explain the obtained results.

  2. Neutron-induced 63Ni activity and microscopic observation of copper samples exposed to the Hiroshima atomic bomb

    Science.gov (United States)

    Shizuma, Kiyoshi; Endo, Satoru; Shinozaki, Kenji; Fukushima, Hiroshi

    2013-05-01

    Fast neutron activation data for 63Ni in copper samples exposed to the Hiroshima atomic bomb are important in evaluating neutron doses to the survivors. Up to until now, accelerator mass spectrometry and liquid scintillation counting methods have been applied in 63Ni measurements and data were accumulated within 1500 m from the hypocenter. The slope of the activation curve versus distance shows reasonable agreement with the calculation result, however, data near the hypocenter are scarce. In the present work, two copper samples obtained from the Atomic bomb dome (155 m from the hypocenter) and the Bank of Japan building (392 m) were utilized in 63Ni beta-ray measurement with a Si surface barrier detector. Additionally, microscopic observation of the metal surfaces was performed for the first time. Only upper limit of 63Ni production was obtained for copper sample of the Atomic bomb dome. The result of the 63Ni measurement for Bank of Japan building show reasonable agreement with the AMS measurement and to fast neutron activation calculations based on the Dosimetry System 2002 (DS02) neutrons.

  3. Evaluation of the microscopic observational drug susceptibility assay for rapid and efficient diagnosis of multi-drug resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    R P Lazarus

    2012-01-01

    Full Text Available Purpose: Tuberculosis (TB is endemic in India and the burden of multi-drug-resistant tuberculosis (MDR-TB is high. Early detection of MDR-TB is of primary importance in controlling the spread of TB. The microscopic observational drug susceptibility (MODS assay has been described as a cost-effective and rapid method by which mycobacterial culture and the drug susceptibility test (DST can be done at the same time. Materials and Methods: A total of 302 consecutive sputum samples that were received in an accredited mycobacteriology laboratory for conventional culture and DST were evaluated by the MODS assay. Results: In comparison with conventional culture on Lowenstein Jensen (LJ media, the MODS assay showed a sensitivity of 94.12% and a specificity of 89.39% and its concordance with the DST by the proportion method on LJ media to isoniazid and rifampicin was 90.8% and 91.5%, respectively. The turnaround time for results by MODS was 9 days compared to 21 days by culture on LJ media and an additional 42 days for DST by the 1% proportion method. The cost of performing a single MODS assay was Rs. 250/-, compared to Rs. 950/- for culture and 1st line DST on LJ. Conclusion: MODS was found to be a sensitive and rapid alternative method for performing culture and DST to identify MDR-TB in resource poor settings.

  4. [Scanning microscopical observations on the foregut structures o mosquitoes and their role for the ingestion of microfilariae (author's transl)].

    Science.gov (United States)

    Buse, E; Kuhlow, F

    1979-12-01

    Experiments on the transmission of Brugia malayi by various mosquitoes had shown that microfilariae ingested by some species were badly damaged when they reached the stomach, but were much less hurt in others. The structures of the foregut likely to cause these injuries, were investigated and documented by scanning microscope techniques. In Anopheles albimanus, A. arabiensis, A. stephensi and A. pharoensis which have well developed armatures the microfilariae showed a high rate of destruction. In A. stroparvus as well as in Aedes aegypti, Ae. togoi and Culex fatigans in which these structures are missing or poorly developed the larvae were much less affected. From the size, shape and position of the different papillae, spines, rods and cones observed it can be concluded and confirmed that the pharyngeal armature (buccopharyngeal bar) will be by far the most important structure responsible for the injuries of the microfilariae. However, it appears that the characteristics of different filaria species can play an important role in preventing such damages.

  5. In situ studies of the atomic layer deposition of thin HfO{sub 2} dielectrics by ultra high vacuum atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Kolanek, Krzysztof, E-mail: kolanek@tu-cottbus.d [Brandenburg University of Technology, Department of Applied Physics and Sensors, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany); Tallarida, Massimo; Karavaev, Konstantin; Schmeisser, Dieter [Brandenburg University of Technology, Department of Applied Physics and Sensors, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany)

    2010-06-01

    We studied in situ the initial stages of atomic layer deposition (ALD) of HfO{sub 2} by an ultra high vacuum atomic force microscope working in frequency-modulation mode. The ALD cycles, made by using tetrakis-di-methyl-amido-Hf and water as precursors, were performed on the Si(001)/SiO{sub 2} substrate maintained at 230 {sup o}C. After each ALD cycle we studied the influence of the HfO{sub 2} growth on the surface height histogram, the root mean square roughness, the surface fractal dimension and the autocorrelation function. This detailed analysis of the surface topography allowed us to confirm the completion of the first HfO{sub 2} layer after four ALD cycles.

  6. Si2Sb2Te5 phase change material studied by an atomic force microscope nano-tip

    Institute of Scientific and Technical Information of China (English)

    Liu Yanbo; Zhang Ting; Niu Xiaoming; Song Zhitang; Min Guoquan; Zhang Jing; Zhou Weimin; Wan Yongzhong; Zhang Jianping; Li Xiaoli; Feng Songlin

    2009-01-01

    The Si2Sb2Te5 phase change material has been studied by applying a nano-tip (30 nm in diameter) on an atomic force microscopy system. Memory switching from a high resistance state to a low resistance state has been achieved, with a resistance change of about 1000 times. In a typical Ⅰ-Ⅴ curve, the current increases significantly after the voltage exceeds~4.3 V. The phase transformation of a Si2Sb2Te5 film was studied in situ by means of in situ X-ray diffraction and temperature dependent resistance measurements. The thermal stability of Si2Sb2Te5 and Ge2Sb2Te5 was characterized and compared as well.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-05-07

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

  9. Method of mechanical holding of cantilever chip for tip-scan high-speed atomic force microscope

    Science.gov (United States)

    Fukuda, Shingo; Uchihashi, Takayuki; Ando, Toshio

    2015-06-01

    In tip-scan atomic force microscopy (AFM) that scans a cantilever chip in the three dimensions, the chip body is held on the Z-scanner with a holder. However, this holding is not easy for high-speed (HS) AFM because the holder that should have a small mass has to be able to clamp the cantilever chip firmly without deteriorating the Z-scanner's fast performance, and because repeated exchange of cantilever chips should not damage the Z-scanner. This is one of the reasons that tip-scan HS-AFM has not been established, despite its advantages over sample stage-scan HS-AFM. Here, we present a novel method of cantilever chip holding which meets all conditions required for tip-scan HS-AFM. The superior performance of this novel chip holding mechanism is demonstrated by imaging of the α3β3 subcomplex of F1-ATPase in dynamic action at ˜7 frames/s.

  10. Method of mechanical holding of cantilever chip for tip-scan high-speed atomic force microscope

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Shingo [Department of Physics, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Uchihashi, Takayuki; Ando, Toshio [Department of Physics, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Bio-AFM Frontier Research Center, College of Science and Engineering, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan); Core Research for Evolutional Science and Technology of the Japan Science and Technology Agency, 7 Goban-cho, Chiyoda-ku, Tokyo 102-0076 (Japan)

    2015-06-15

    In tip-scan atomic force microscopy (AFM) that scans a cantilever chip in the three dimensions, the chip body is held on the Z-scanner with a holder. However, this holding is not easy for high-speed (HS) AFM because the holder that should have a small mass has to be able to clamp the cantilever chip firmly without deteriorating the Z-scanner’s fast performance, and because repeated exchange of cantilever chips should not damage the Z-scanner. This is one of the reasons that tip-scan HS-AFM has not been established, despite its advantages over sample stage-scan HS-AFM. Here, we present a novel method of cantilever chip holding which meets all conditions required for tip-scan HS-AFM. The superior performance of this novel chip holding mechanism is demonstrated by imaging of the α{sub 3}β{sub 3} subcomplex of F{sub 1}-ATPase in dynamic action at ∼7 frames/s.

  11. Direct nitrate reductase assay versus microscopic observation drug susceptibility test for rapid detection of MDR-TB in Uganda.

    Directory of Open Access Journals (Sweden)

    Freddie Bwanga

    Full Text Available The most common method for detection of drug resistant (DR TB in resource-limited settings (RLSs is indirect susceptibility testing on Lowenstein-Jensen medium (LJ which is very time consuming with results available only after 2-3 months. Effective therapy of DR TB is therefore markedly delayed and patients can transmit resistant strains. Rapid and accurate tests suitable for RLSs in the diagnosis of DR TB are thus highly needed. In this study we compared two direct techniques--Nitrate Reductase Assay (NRA and Microscopic Observation Drug Susceptibility (MODS for rapid detection of MDR-TB in a high burden RLS. The sensitivity, specificity, and proportion of interpretable results were studied. Smear positive sputum was collected from 245 consecutive re-treatment TB patients attending a TB clinic in Kampala, Uganda. Samples were processed at the national reference laboratory and tested for susceptibility to rifampicin and isoniazid with direct NRA, direct MODS and the indirect LJ proportion method as reference. A total of 229 specimens were confirmed as M. tuberculosis, of these interpretable results were obtained in 217 (95% with either the NRA or MODS. Sensitivity, specificity and kappa agreement for MDR-TB diagnosis was 97%, 98% and 0.93 with the NRA; and 87%, 95% and 0.78 with the MODS, respectively. The median time to results was 10, 7 and 64 days with NRA, MODS and the reference technique, respectively. The cost of laboratory supplies per sample was low, around 5 USD, for the rapid tests. The direct NRA and MODS offered rapid detection of resistance almost eight weeks earlier than with the reference method. In the study settings, the direct NRA was highly sensitive and specific. We consider it to have a strong potential for timely detection of MDR-TB in RLS.

  12. Celiac disease, collagenous sprue and microscopic colitis in IBD. Observations from a population-based cohort of IBD (ICURE).

    Science.gov (United States)

    Rönnblom, Anders; Holmström, Tommy; Tanghöj, Hans; Wanders, Alkwin; Sjöberg, Daniel

    2015-01-01

    Inflammatory bowel disease (IBD), microscopic colitis and celiac disease are all diseases with worldwide distribution and increased incidence has been reported from many areas. There is a shortage of studies investigating the occurrence of these diseases in the same individual and whether those affected demonstrate any particular phenotype. The aim of the study was to describe the concomitant incidence of microscopic colitis and celiac disease in a population-based IBD cohort. All 790 individuals in a prospective population-based cohort included 2005-09 from Uppsala region, Sweden, were reviewed regarding the appearance of microscopic or celiac disease before or after IBD diagnosis. Fifty percent (396/790) of the patients had been examined for the possibility of celiac disease. Seventeen patients with celiac disease were found, representing 2.2% of the cohort. Patients with celiac disease were younger compared to the non-celiac patients and those with colitis had more often an extensive inflammation of the colon. Seventy-one percent (12/17) were women. The majority of the patients were diagnosed with celiac disease before IBD. Five patients with IBD had an earlier diagnosis of microscopic colitis or developed it after the IBD diagnosis. One teenager developed collagenous sprue, misinterpreted as a severe relapse of ulcerative colitis (UC) resulting in colectomy. The risk for celiac disease seems not to be increased in IBD, but those affected by both diseases seem to be predominantly women with extensive UC. There is a potential association between microscopic colitis and IBD.

  13. Force

    CERN Document Server

    Graybill, George

    2007-01-01

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

  14. Leptospiral outer membrane lipoprotein LipL32 binding on toll-like receptor 2 of renal cells as determined with an atomic force microscope.

    Science.gov (United States)

    Hsu, Shen-Hsing; Lo, Yueh-Yu; Tung, Jung-Yu; Ko, Yi-Ching; Sun, Yuh-Ju; Hung, Cheng-Chieh; Yang, Chih-Wei; Tseng, Fan-Gang; Fu, Chien-Chung; Pan, Rong-Long

    2010-07-06

    Leptopirosis is a renal disease caused by pathogenic Leptospira that primarily infects the renal proximal tubules, consequently resulting in severe tubular injuries and malfunctions. The protein extracted from the outer membrane of this pathogenic strain contains a major component of a 32 kDa lipoprotein (LipL32), which is absent in the counter membrane of nonpathogenic strains and has been identified as a crucial factor for host cell infection. Previous studies showed that LipL32 induced inflammatory responses and interacted with the extracellular matrix (ECM) of the host cell. However, the exact relationship between LipL32-mediated inflammatory responses and ECM binding is still unknown. In this study, an atomic force microscope with its tip modified by purified LipL32 was used to assess the interaction between LipL32 and cell surface receptors. Furthermore, an antibody neutralization technique was employed to identify Toll-like receptor 2 (TLR2) but not TLR4 as the major target of LipL32 attack. The interaction force between LipL32 and TLR2 was measured as approximately 59.5 +/- 8.7 pN, concurring with the theoretical value for a single-pair molecular interaction. Moreover, transformation of a TLR deficient cell line with human TLR2 brought the interaction force from the basal level to approximately 60.4 +/- 11.5 pN, confirming unambiguously TLR2 as counter receptor for LipL32. The stimulation of CXCL8/IL-8 expression by full-length LipL32 as compared to that without the N-terminal signal peptide domain suggests a significant role of the signal peptide of the protein in the inflammatory responses. This study provides direct evidence that LipL32 binds to TLR2, but not TLR4, on the cell surface, and a possible mechanism for the virulence of leptospirosis is accordingly proposed.

  15. Observing Fluorescent Probes in Living Cells using a Low-Cost LED Flashlight Retrofitted to a Common Vintage Light Microscope

    Directory of Open Access Journals (Sweden)

    G. A. Babbitt

    2013-03-01

    Full Text Available While the application of molecular biological techniques based upon fluorescent probes has rapidly expanded over recent decades, the equipment cost of fluorescent microscopy has largely prevented its adoption in the college and high school classroom. We offer a simple solution to this problem by describing in detail how to build with simple tools, a fluorescent microscope using a common brand of colored LED flashlights and second-hand components of vintage Nikon microscopes. This extremely low cost solution is qualitatively compared to an expensive modern Zeiss system.

  16. The observation of the fine structure of bamboo cell wall with SEM, AFM and multi-media microscope%三种仪器用于竹纤维细胞壁观察的效果比较

    Institute of Scientific and Technical Information of China (English)

    张宁; 张美云; 夏新兴

    2013-01-01

    In this paper, the fibrillation of bamboo fibers was observed with scanning electron microscopy, multi-media microscope and atomic force microscopy. The results show that all of the three instruments can be used to observe the fibrillation of fibers. The stripping process of the outermost secondary wall and the microfibril angle to the axis can be clearly observed most small in scanning electron microscopy, and the microfibril almost parallel to axis can be seen. The observation of atomic force microscopy shows that the surface of fiber becomes smooth after the stripping of the outermost secondary wall. The overall fibrillation of fiber can be observed in multi-media microscope. It was found that the observation of stripping process of cell wall combined with scanning electron microscopy, multi-media microscope and atomic force microscopy is a new approach to study the mechanism of beating.%  利用扫描电镜,多媒体显微镜和原子力显微镜三种仪器观察竹纤维分丝帚化情况和细胞壁的破裂情况。结果发现:利用扫描电子显微镜清晰地观察到竹纤维次生壁的剥离过程,而且可以看到竹纤维次生壁外层的微纤维与细胞轴向之间的夹角很小,几乎与轴平行;用原子力显微镜观察到次生壁外层完全剥离之后,纤维表面变得光滑;用多媒体显微镜能够较好地观察低倍数下纤维的分丝帚化。用这三种仪器结合起来观察纤维打浆过程中的细胞壁破裂情况,是一种研究磨浆机理的新方法。

  17. How to observe the giant thermal effect in the Casimir force for graphene systems

    Science.gov (United States)

    Bimonte, G.; Klimchitskaya, G. L.; Mostepanenko, V. M.

    2017-07-01

    A differential measurement scheme is proposed which allows for clear observation of the giant thermal effect for the Casimir force, which was recently predicted to occur in graphene systems at short separation distances. The difference among the Casimir forces acting between a metal-coated sphere and the two halves of a dielectric plate, one uncoated and the other coated with graphene, is calculated in the framework of the Dirac model using the rigorous formalism of the polarization tensor. It is shown that in the proposed configuration both the difference among the Casimir forces and its thermal contribution can be easily measured using existing experimental setups. An observation of the giant thermal effect should open opportunities for modulation and control of dispersion forces in micromechanical systems based on graphene and other novel two-dimensional (2D) materials.

  18. Observation of three-level rectified dipole forces acting on trapped atoms

    Science.gov (United States)

    Grove, T. T.; Duncan, B. C.; Sanchez-Villicana, V.; Gould, P. L.

    1995-06-01

    We have observed rectified dipole forces acting on three-level atoms in the cascade configuration. Laser cooled and trapped rubidium atoms are illuminated with an intense bichromatic standing wave (780 and 776 nm) tuned near resonance with the 5S1/2-->5P3/2-->5D5/2 transitions. The resulting rectified forces produce periodic potential wells (71-μm period), which localize the cold atoms. Experimental results are in reasonable agreement with theoretical predictions. These forces may be useful in atom optics and laser traps.

  19. Observation of DNA Molecules Using Fluorescence Microscopy and Atomic Force Microscopy

    Science.gov (United States)

    Ito, Takashi

    2008-01-01

    This article describes experiments for an undergraduate instrumental analysis laboratory that aim to observe individual double-stranded DNA (dsDNA) molecules using fluorescence microscopy and atomic force microscopy (AFM). dsDNA molecules are observed under several different conditions to discuss their chemical and physical properties. In…

  20. Observation of DNA Molecules Using Fluorescence Microscopy and Atomic Force Microscopy

    Science.gov (United States)

    Ito, Takashi

    2008-01-01

    This article describes experiments for an undergraduate instrumental analysis laboratory that aim to observe individual double-stranded DNA (dsDNA) molecules using fluorescence microscopy and atomic force microscopy (AFM). dsDNA molecules are observed under several different conditions to discuss their chemical and physical properties. In…

  1. Global Positioning System: Observations on Quarterly Reports from the Air Force

    Science.gov (United States)

    2016-10-17

    Positioning System: Observations on Quarterly Reports from the Air Force The satellite-based Global Positioning System (GPS) provides positioning, navigation...infrastructure, and transportation safety. The Department of Defense (DOD)—specifically, the Air Force—develops and operates the GPS system, which...National Defense Authorization Act for Fiscal Year 2016 contained a provision that the Air Force provide quarterly reports to GAO on the next

  2. Living Matter Observations with a Novel Hyperspectral Supercontinuum Confocal Microscope for VIS to Near-IR Reflectance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Francesca R. Bertani

    2013-10-01

    Full Text Available A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods.

  3. Living matter observations with a novel hyperspectral supercontinuum confocal microscope for VIS to near-IR reflectance spectroscopy.

    Science.gov (United States)

    Bertani, Francesca R; Ferrari, Luisa; Mussi, Valentina; Botti, Elisabetta; Costanzo, Antonio; Selci, Stefano

    2013-10-25

    A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods.

  4. [Aging effect on mechanical properties in fluid resin. (Part 3) Affection of residual monomer on the surface morphology after tensile test by microscopic observation (author's transl)].

    Science.gov (United States)

    Horiuchi, A

    1981-04-01

    Affection of residual monomer on the surface morphology after tensile test was observed by an scanning microscope. Evaporation or leaching of the monomer gave big influence on the morphology of pearls and matrix. The observation suggested that the residual monomer existed mainly in the matrix. When the residual monomer disappeared, the surface morphology did not change by tensile load. It is the most important point to get good denture with fluid resin that we could decrease the residual monomer as possible.

  5. Evaluation of microscopic observation drug susceptibility assay for diagnosis of multidrug-resistant Tuberculosis in Viet Nam

    Directory of Open Access Journals (Sweden)

    Minh Ha Dang

    2012-03-01

    Full Text Available Abstract Background Early diagnosis of tuberculosis (TB and multidrug resistant tuberculosis (MDR TB is important for the elimination of TB. We evaluated the microscopic observation drug susceptibility (MODS assay as a direct rapid drug susceptibility testing (DST method for MDR-TB screening in sputum samples Methods All adult TB suspects, who were newly presenting to Pham Ngoc Thach Hospital from August to November 2008 were enrolled into the study. Processed sputum samples were used for DST by MODS (DST-MODS (Rifampicin (RIF 1 μg/ml and Isoniazid (INH 0.4 μg/ml, MGIT culture (Mycobacterial Growth Indicator Tube and Lowenstein Jensen (LJ culture. Cultures positive by either MGIT or LJ were used for proportional DST (DST-LJ (RIF 40 μg/ml and INH 0.2 μg/ml. DST profiles on MODS and LJ were compared. Discrepant results were resolved by multiplex allele specific PCR (MAS-PCR. Results Seven hundred and nine TB suspects/samples were enrolled into the study, of which 300 samples with DST profiles available from both MODS and DST-LJ were analyzed. Cording in MODS was unable to correctly identify 3 Mycobacteria Other Than Tuberculosis (MOTT isolates, resulting in 3 false positive TB diagnoses. None of these isolates were identified as MDR-TB by MODS. The sensitivity and specificity of MODS were 72.6% (95%CI: 59.8, 83.1 and 97.9% (95%CI: 95.2, 99.3, respectively for detection of INH resistant isolates, 72.7% (95%CI: 30.9, 93.7 and 99.7% (95%CI: 98.1, 99.9, respectively for detecting RIF resistant isolates and 77.8% (95%CI: 39.9, 97.1 and 99.7% (95%CI: 98.1, 99.9, respectively for detecting MDR isolates. The positive and negative predictive values (PPV and NPV of DST-MODS were 87.5% (95%CI: 47.3, 99.6 and 99.3% (95%CI: 97.5, 99.9 for detection of MDR isolates; and the agreement between MODS and DST-LJ was 99.0% (kappa: 0.8, P Conclusion The DST-MODS technique is rapid with low contamination rates. However, the sensitivity of DST-MODS for detection of

  6. Biochemical, electron microscopic and immunohistological observations of cationic detergent-extracted cells: detection and improved preservation of microextensions and ultramicroextensions

    Directory of Open Access Journals (Sweden)

    Nakamura Fumihiko

    2001-06-01

    Full Text Available Abstract Background Filopodia, retraction fibers and microvilli, are fragile microextensions of the plasma membrane that are easily damaged by mechanical force during specimen preparation for microscopy. To preserve these structures for electron microscopy glutaraldehyde is generally used, but it often causes antigen masking. By contrast, formaldehyde is generally used for immunofluorescence light microscopy, but few studies have been concerned with the loss of microextensions. Results We demonstrate in biochemical experiments that cultured cells needed to be kept in 4% formaldehyde for at least 60 min at room temperature or for 20 min at 37°C to irreversibly crosslink most of the polypeptides. Also, fragmentation of fragile microextensions was observed after Triton X-100 extraction depending on concentration and extent of crosslinking. We also report on a novel fixation procedure that includes the cationic detergent dodecyltrimethylammonium chloride (DOTMAC. Treatment of NIH3T3 cells with DOTMAC resulted in complete removal of membrane lipids and in good preservation of the cytoskeleton in microextensions as well as preservation of ultramicroextensions of Conclusions Some microextensions were fragmented by the standard Triton X-100 permeabilization method. By contrast, DOTMAC completely extracted membrane lipids while maintaining the cytoskeleton of microextensions. Thus, DOTMAC treatment may provide a valuable new tool for the reliable visualization of previously undetectable or poorly detectable antigens while preserving the actin cytoskeleton of microextensions.

  7. Observations and morphological analysis of supermolecular structure of natural bitumens by atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yevgeny A. Golubev; Olga V. Kovaleva; Nikolay P. Yushkin [Institute of Geology of RAS, Syktyvkar (Russian Federation)

    2008-01-15

    The supermolecular structures of natural bitumens of the thermal consequent row asphaltites lower kerites (albertites), higher kerites (impsonites), anthraxolites from the Timan-Pechora petroleum province and Karelian shungite rocks, Russia, were studied in details. The experimental technique used was atomic force microscopy (AFM), following fracture preparation. The element distribution of the sample surfaces was analyzed by an X-ray microanalyser 'Link ISIS', combined with a scanning electron microscope (SEM). In this work, we characterized the supermolecular evolution of natural solid bitumens in the carbonization sequence by quantitative parameters. We showed that supermolecular structure can be important in defining to which classification group solid bitumens belong. 29 refs., 7 figs., 2 tabs.

  8. Spin observables in nucleon-deuteron scattering and three-nucleon forces

    CERN Document Server

    Ishikawa, S; Iseri, Y

    2002-01-01

    Three-nucleon forces, which compose an up-to-date subject in few-nucleon systems, provide a good account of the triton binding energy and the cross section minimum in proton-deuteron elastic scattering, while do not succeed in explaining spin observables such as the nucleon and deuteron analyzing powers, suggesting serious defects in their spin dependence. We study the spin structure of nucleon-deuteron elastic amplitudes by decomposing them into spin-space tensors and examine effects of three-nucleon forces to each component of the amplitudes obtained by solving the Faddeev equation. Assuming that the spin-scalar amplitudes dominate the others, we derive simple expressions for spin observables in the nucleon-deuteron elastic scattering. The expressions suggest that a particular combination of spin observables in the scattering provides direct information of scalar, vector, or tensor component of the three-nucleon forces. These effects are numerically investigated by the Faddeev calculation.

  9. Observation of the Field, Current and Force Distributions in an Optimized Superconducting Levitation with Translational Symmetry

    Science.gov (United States)

    Ye, Chang-Qing; Ma, Guang-Tong; Liu, Kun; Wang, Jia-Su

    2016-08-01

    The superconducting levitation realized by immersing the high-temperature superconductors (HTSs) into nonuniform magnetic field is deemed promising in a wide range of industrial applications such as maglev transportation and kinetic energy storage. Using a well-established electromagnetic model to mathematically describe the HTS, we have developed an efficient scheme that is capable of intelligently and globally optimizing the permanent magnet guideway (PMG) with single or multiple HTSs levitated above for the maglev transportation applications. With maximizing the levitation force as the principal objective, we optimized the dimensions of a Halbach-derived PMG to observe how the field, current and force distribute inside the HTSs when the optimized situation is achieved. Using a pristine PMG as a reference, we have analyzed the critical issues for enhancing the levitation force through comparing the field, current and force distributions between the optimized and pristine PMGs. It was also found that the optimized dimensions of the PMG are highly dependent upon the levitated HTS. Moreover, the guidance force is not always contradictory to the levitation force and may also be enhanced when the levitation force is prescribed to be the principle objective, depending on the configuration of levitation system and lateral displacement.

  10. Observation of the Field, Current and Force Distributions in an Optimized Superconducting Levitation with Translational Symmetry

    Science.gov (United States)

    Ye, Chang-Qing; Ma, Guang-Tong; Liu, Kun; Wang, Jia-Su

    2017-01-01

    The superconducting levitation realized by immersing the high-temperature superconductors (HTSs) into nonuniform magnetic field is deemed promising in a wide range of industrial applications such as maglev transportation and kinetic energy storage. Using a well-established electromagnetic model to mathematically describe the HTS, we have developed an efficient scheme that is capable of intelligently and globally optimizing the permanent magnet guideway (PMG) with single or multiple HTSs levitated above for the maglev transportation applications. With maximizing the levitation force as the principal objective, we optimized the dimensions of a Halbach-derived PMG to observe how the field, current and force distribute inside the HTSs when the optimized situation is achieved. Using a pristine PMG as a reference, we have analyzed the critical issues for enhancing the levitation force through comparing the field, current and force distributions between the optimized and pristine PMGs. It was also found that the optimized dimensions of the PMG are highly dependent upon the levitated HTS. Moreover, the guidance force is not always contradictory to the levitation force and may also be enhanced when the levitation force is prescribed to be the principle objective, depending on the configuration of levitation system and lateral displacement.

  11. Direct Radiative Forcing of Anthropogenic Aerosols over Oceans from Satellite Observations

    Institute of Scientific and Technical Information of China (English)

    CHEN Lin; SHI Guangyu; QIN Shiguang; YANG Su; ZHANG Peng

    2011-01-01

    Anthropogenic aerosols play an important role in the atmospheric energy balance. Anthropogenic aerosol optical depth (AOD) and its accompanying shortwave radiative forcing (RF) are usually simulated by numerical models. Recently, with the development of space-borne instruments and sophisticated retrieval algorithms, it has become possible to estimate aerosol radiative forcing based on satellite observations. In this study, we have estimated shortwave direct radiative forcing due to anthropogenic aerosols over oceans in all-sky conditions by combining clouds and the Single Scanner Footprint data of the Clouds and Earth's Radiant Energy System (CERES/SSF) experiment, which provide measurements of upward shortwave fluxes at the top of atmosphere, with Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol and cloud products. We found that globally averaged aerosol radiative forcing over oceans in the clear-sky conditions and all-sky conditions were -1.03±0.48 W m-2 and -0.34 ±0.16 W m-2, respectively. Direct radiative forcing by anthropogenic aerosols shows large regional and seasonal variations. In some regions and in particular seasons, the magnitude of direct forcing by anthropogenic aerosols can be comparable to the forcing of greenhouse gases. However, it shows that aerosols caused the cooling effect, rather than warming effect from global scale, which is different from greenhouse gases.

  12. Effect of surface finishing on early-stage corrosion of a carbon steel studied by electrochemical and atomic force microscope characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuan; Cheng, Y. Frank, E-mail: fcheng@ucalgary.ca

    2016-03-15

    Graphical abstract: - Highlights: • Imaged the topography of steel with various surface roughness. • Monitored the early-stage corrosion of steel by AFM. • Derived the corrosion growth at nano-scale surface features. - Abstract: In this work, the early-stage corrosion of a carbon steel with various surface roughness, which was created by different levels of surface finishing treatment, was characterized by an atomic force microscope and electrochemical measurements. It is found that the resulting surface roughness is at nano-meter scale. As the surface roughness increases, the corrosion activity of the steel is increased. The early-stage corrosion of the steel is featured with two stages of dissolution. While the first stage involves a rapid dissolution and increasing surface roughness of the steel, stage two is in an equilibrium state to have an approximately constant corrosion rate and surface roughness. Generally, the corrosion rate of the steel decreases when the surface finish of the specimen becomes finer. Local preferential corrosion occurs at surface irregularities, resulting in the deepening and widening of the features such as scratches with time.

  13. Combined Atomic Force Microscope-Based Topographical Imaging and Nanometer Scale Resolved Proximal Probe Thermal Desorption/Electrospray Ionization-Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ovchinnikova, Olga S [ORNL; Nikiforov, Maxim [ORNL; Bradshaw, James A [ORNL; Jesse, Stephen [ORNL; Van Berkel, Gary J [ORNL

    2011-01-01

    Nanometer scale proximal probe thermal desorption/electrospray ionization mass spectrometry (TD/ESI-MS) was demonstrated for molecular surface sampling of caffeine from a thin film using a 30 nm diameter nano-thermal analysis (nano-TA) probe tip in an atomic force microscope (AFM) coupled via a vapor transfer line and ESI interface to a MS detection platform. Using a probe temperature of 350 C and a spot sampling time of 30 s, conical desorption craters 250 nm in diameter and 100 nm deep were created as shown through subsequent topographical imaging of the surface within the same system. Automated sampling of a 5 x 2 array of spots, with 2 m spacing between spots, and real time selective detection of the desorbed caffeine using tandem mass spectrometry was also demonstrated. Estimated from the crater volume (~2x106 nm3), only about 10 amol (2 fg) of caffeine was liberated from each thermal desorption crater in the thin film. These results illustrate a relatively simple experimental setup and means to acquire in automated fashion sub-micrometer scale spatial sampling resolution and mass spectral detection of materials amenable to TD. The ability to achieve MS-based chemical imaging with 250 nm scale spatial resolution with this system is anticipated.

  14. Microscopic analysis and histochemical observations of the medicinal root of Iostephane heterophylla (Cav.) Benth. ex Hemsl. (Asteraceae)

    OpenAIRE

    Estela Sandoval; Robert A. Bye; Griselda Ríos; María Isabel Aguilar

    2005-01-01

    The roots of Iostephane heterophylla are popular in Mexican traditional medicine and as such are a good candidate to develop herbal drug preparations to be used as phytomedicine. International criteria for validation and standardization of a herbal product as phytomedicine include, among others, the integration of microscopic and histochemical characteristics of the raw material, as in this case the herbal drug, to guarantee its authenticity. As an original contribution to the knowledge of th...

  15. Effect of linear alkyl benzene sulfonate in skin of fish fingerlings (Cirrhina mrigala): observations with scanning electron microscope.

    Science.gov (United States)

    Misra, V; Chawla, G; Kumar, V; Lal, H; Viswanathan, P N

    1987-04-01

    Pathomorphological changes in the skin was noticed under the scanning electron microscope in fish fingerlings (Cirrhina mrigala) exposed to 0.005 ppm (25% of the LC50) concentration to linear alkyl benzene sulfonate. The epithelial cells present in the epidermis of the skin were found to secrete more mucus with linear alkyl benzene sulfonate (LAS) than did controls. The presence or deposition of mucus on the surface of skin indicated likely molecular interaction between constituents of mucus and LAS.

  16. Diagnosis of cervical cancer cell taken from scanning electron and atomic force microscope images of the same patients using discrete wavelet entropy energy and Jensen Shannon, Hellinger, Triangle Measure classifier

    Science.gov (United States)

    Aytac Korkmaz, Sevcan

    2016-05-01

    The aim of this article is to provide early detection of cervical cancer by using both Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) images of same patient. When the studies in the literature are examined, it is seen that the AFM and SEM images of the same patient are not used together for early diagnosis of cervical cancer. AFM and SEM images can be limited when using only one of them for the early detection of cervical cancer. Therefore, multi-modality solutions which give more accuracy results than single solutions have been realized in this paper. Optimum feature space has been obtained by Discrete Wavelet Entropy Energy (DWEE) applying to the 3 × 180 AFM and SEM images. Then, optimum features of these images are classified with Jensen Shannon, Hellinger, and Triangle Measure (JHT) Classifier for early diagnosis of cervical cancer. However, between classifiers which are Jensen Shannon, Hellinger, and triangle distance have been validated the measures via relationships. Afterwards, accuracy diagnosis of normal, benign, and malign cervical cancer cell was found by combining mean success rates of Jensen Shannon, Hellinger, and Triangle Measure which are connected with each other. Averages of accuracy diagnosis for AFM and SEM images by averaging the results obtained from these 3 classifiers are found as 98.29% and 97.10%, respectively. It has been observed that AFM images for early diagnosis of cervical cancer have higher performance than SEM images. Also in this article, surface roughness of malign AFM images in the result of the analysis made for the AFM images, according to the normal and benign AFM images is observed as larger, If the volume of particles has found as smaller. She has been a Faculty Member at Fırat University in the Electrical- Electronic Engineering Department since 2007. Her research interests include image processing, computer vision systems, pattern recognition, data fusion, wavelet theory, artificial neural

  17. Diagnosis of cervical cancer cell taken from scanning electron and atomic force microscope images of the same patients using discrete wavelet entropy energy and Jensen Shannon, Hellinger, Triangle Measure classifier.

    Science.gov (United States)

    Aytac Korkmaz, Sevcan

    2016-05-05

    The aim of this article is to provide early detection of cervical cancer by using both Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) images of same patient. When the studies in the literature are examined, it is seen that the AFM and SEM images of the same patient are not used together for early diagnosis of cervical cancer. AFM and SEM images can be limited when using only one of them for the early detection of cervical cancer. Therefore, multi-modality solutions which give more accuracy results than single solutions have been realized in this paper. Optimum feature space has been obtained by Discrete Wavelet Entropy Energy (DWEE) applying to the 3×180 AFM and SEM images. Then, optimum features of these images are classified with Jensen Shannon, Hellinger, and Triangle Measure (JHT) Classifier for early diagnosis of cervical cancer. However, between classifiers which are Jensen Shannon, Hellinger, and triangle distance have been validated the measures via relationships. Afterwards, accuracy diagnosis of normal, benign, and malign cervical cancer cell was found by combining mean success rates of Jensen Shannon, Hellinger, and Triangle Measure which are connected with each other. Averages of accuracy diagnosis for AFM and SEM images by averaging the results obtained from these 3 classifiers are found as 98.29% and 97.10%, respectively. It has been observed that AFM images for early diagnosis of cervical cancer have higher performance than SEM images. Also in this article, surface roughness of malign AFM images in the result of the analysis made for the AFM images, according to the normal and benign AFM images is observed as larger, If the volume of particles has found as smaller.

  18. Chemotaxis study using optical tweezers to observe the strength and directionality of forces of Leishmania amazonensis

    Science.gov (United States)

    Pozzo, Liliana d. Y.; Fontes, Adriana; de Thomaz, André A.; Barbosa, Luiz C.; Ayres, Diana C.; Giorgio, Selma; Cesar, Carlos L.

    2006-08-01

    The displacements of a dielectric microspheres trapped by an optical tweezers (OT) can be used as a force transducer for mechanical measurements in life sciences. This system can measure forces on the 50 femto Newtons to 200 pico Newtons range, of the same order of magnitude of a typical forces induced by flagellar motion. The process in which living microorganisms search for food and run away from poison chemicals is known is chemotaxy. Optical tweezers can be used to obtain a better understanding of chemotaxy by observing the force response of the microorganism when placed in a gradient of attractors and or repelling chemicals. This report shows such observations for the protozoa Leishmania amazomenzis, responsible for the leishmaniasis, a serious tropical disease. We used a quadrant detector to monitor the movement of the protozoa for different chemicals gradient. This way we have been able to observe both the force strength and its directionality. The characterization of the chemotaxis of these parasites can help to understand the infection mechanics and improve the diagnosis and the treatments employed for this disease.

  19. Microscopic driving force in electronic smectic-nematic transition in La1/3Ca2/3MnO3

    Science.gov (United States)

    Tao, Jing; Sun, K.; Yin, W. G.; Pennycook, S. J.; Tranquada, J. M.; Zhu, Y.

    2015-03-01

    Electronic liquid crystal (ELC) phases provide unique descriptions to characterize the electronic structures and elucidate the underlying physics in correlated materials from symmetry perspective. Although ELC phases have been proposed to play a key role in interpreting the structure-property relationship in a wide range of correlated materials, the experimental manifestations of the nature of the transition between such phases have been waiting to be explored. Using transmission electron microscopic tools with recently developed techniques, we studied the electronic smectic-nematic phase transition in La1/3Ca2/3MnO3 by monitoring the evolution of charge ordering and orbital ordering superstructures as a function of temperature. We observed that the transition is driven by the formation of defects and electronic phase separation. In addition, we found that charge inhomogeneity is responsible for the electronic smectic-nematic phase transition in this material.

  20. Microscopic origin of the 1.3 G(0) conductance observed in oxygen-doped silver quantum point contacts.

    Science.gov (United States)

    Tu, Xingchen; Wang, Minglang; Sanvito, Stefano; Hou, Shimin

    2014-11-21

    Besides the peak at one conductance quantum, G0, two additional features at ∼0.4 G0 and ∼1.3 G0 have been observed in the conductance histograms of silver quantum point contacts at room temperature in ambient conditions. In order to understand such feature, here we investigate the electronic transport and mechanical properties of clean and oxygen-doped silver atomic contacts by employing the non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that, unlike clean Ag single-atom contacts showing a conductance of 1 G0, the low-bias conductance of oxygen-doped Ag atomic contacts depends on the number of oxygen impurities and their binding configuration. When one oxygen atom binds to an Ag monatomic chain sandwiched between two Ag electrodes, the low-bias conductance of the junction always decreases. In contrast, when the number of oxygen impurities is two and the O-O axis is perpendicular to the Ag-Ag axis, the transmission coefficients at the Fermi level are, respectively, calculated to be 1.44 for the junction with Ag(111) electrodes and 1.24 for that with Ag(100) electrodes, both in good agreement with the measured value of ∼1.3 G0. The calculated rupture force (1.60 nN for the junction with Ag(111) electrodes) is also consistent with the experimental value (1.66 ± 0.09 nN), confirming that the measured ∼1.3 G0 conductance should originate from Ag single-atom contacts doped with two oxygen atoms in a perpendicular configuration.

  1. Microscopic origin of the 1.3 G0 conductance observed in oxygen-doped silver quantum point contacts

    KAUST Repository

    Tu, Xingchen

    2014-11-21

    © 2014 AIP Publishing LLC. Besides the peak at one conductance quantum, G0, two additional features at ∼0.4 G0 and ∼1.3 G0 have been observed in the conductance histograms of silver quantum point contacts at room temperature in ambient conditions. In order to understand such feature, here we investigate the electronic transport and mechanical properties of clean and oxygen-doped silver atomic contacts by employing the non-equilibrium Green\\'s function formalism combined with density functional theory. Our calculations show that, unlike clean Ag single-atom contacts showing a conductance of 1 G0, the low-bias conductance of oxygen-doped Ag atomic contacts depends on the number of oxygen impurities and their binding configuration. When one oxygen atom binds to an Ag monatomic chain sandwiched between two Ag electrodes, the low-bias conductance of the junction always decreases. In contrast, when the number of oxygen impurities is two and the O-O axis is perpendicular to the Ag-Ag axis, the transmission coefficients at the Fermi level are, respectively, calculated to be 1.44 for the junction with Ag(111) electrodes and 1.24 for that with Ag(100) electrodes, both in good agreement with the measured value of ∼1.3 G0. The calculated rupture force (1.60 nN for the junction with Ag(111) electrodes) is also consistent with the experimental value (1.66 ± 0.09 nN), confirming that the measured ∼1.3 G0 conductance should originate from Ag single-atom contacts doped with two oxygen atoms in a perpendicular configuration.

  2. Microscope basics.

    Science.gov (United States)

    Sluder, Greenfield; Nordberg, Joshua J

    2013-01-01

    This chapter provides information on how microscopes work and discusses some of the microscope issues to be considered in using a video camera on the microscope. There are two types of microscopes in use today for research in cell biology-the older finite tube-length (typically 160mm mechanical tube length) microscopes and the infinity optics microscopes that are now produced. The objective lens forms a magnified, real image of the specimen at a specific distance from the objective known as the intermediate image plane. All objectives are designed to be used with the specimen at a defined distance from the front lens element of the objective (the working distance) so that the image formed is located at a specific location in the microscope. Infinity optics microscopes differ from the finite tube-length microscopes in that the objectives are designed to project the image of the specimen to infinity and do not, on their own, form a real image of the specimen. Three types of objectives are in common use today-plan achromats, plan apochromats, and plan fluorite lenses. The concept of mounting video cameras on the microscope is also presented in the chapter. Copyright © 2003 Elsevier Inc. All rights reserved.

  3. Observations of gravity wave forcing of themesopause region during the January 2013 major Sudden Stratospheric Warming

    CERN Document Server

    deWit, R J; Espy, P J; Orsolini, Y J; Limpasuvan, V; Kinnison, D E

    2016-01-01

    Studies of vertical and interhemispheric coupling during Sudden Stratospheric Warmings (SSWs) suggest that gravity wave (GW) momentum flux divergence plays a key role in forcing the middle atmosphere, although observational validation of GW forcing is limited. We present a whole atmosphere view of zonal winds from the surface to 100 km during the January 2013 major SSW, together with observed GW momentum fluxes in the mesopause region derived from uninterrupted high-resolution meteor radar observations from an All-Sky Interferometric Meteor Radar system located at Trondheim, Norway (63.4 $^{\\circ}$N, 10.5 $^{\\circ}$E). Observations show GW momentum flux divergence 6 days prior to the SSW onset, producing an eastward forcing with peak values of $\\sim$+145 $\\pm$ 60m $s^{-1}$ $d^{-1}$. As the SSW evolves, GW forcing turns westward, reaching a minimum of $\\sim$-240 $\\pm$ 70 m $s^{-1}$ $d^{-1}$ $\\sim$+18 days after the SSW onset. These results are discussed in light of previous studies and simulations using the Wh...

  4. Observational evidence for remote forcing of the west India coastal current

    Digital Repository Service at National Institute of Oceanography (India)

    Shetye, S.R.; Suresh, I.; Shankar, D.; Sundar, D.; Jayakumar, S.; Mehra, P.; Desai, R.G.P.; Pednekar, P.S.

    remote and local forcing in observations. Using field measurements (current, sea level, and wind) for a month during March-April 2003 off Goa in the near-coast regime of the West India Coastal Current (WICC), we show that the current was driven by local...

  5. Improved hybrid position/force controller design of a flexible robot manipulator using a sliding observer

    Institute of Scientific and Technical Information of China (English)

    Farooq M; Wang Daobo; Dar N. U

    2009-01-01

    An improved hybrid position/force controller design of a flexible robot manipulator is presented using a sliding observer. The friction between the end effector and the environment is considered and compensated. For systematic reasons the controller is designed taking into consideration the rigid link subsystems and the flexible joints. The proposed control system satisfies the stability of the two subsystems and copes with the uncertainty of robot dynamics. A sliding observer is designed to estimate the time derivative of the torque applied as input to the rigid part of the robot. For the stability of the observer, it is assumed that the uncertainty of the observed system is bounded. A MRAC algorithm is used for the estimation of the friction forces at the contact point between the end effector and the environment. Finally simulation and experimental results are given, to demonstrate the effectiveness of the proposed controller.

  6. Observation of Phase Objects by Using an X-ray Microscope with a Foucault Knife-Edge

    Science.gov (United States)

    Watanabe, N.; Sasaya, T.; Imai, Y.; Iwata, S.; Zama, K.; Aoki, S.

    2011-09-01

    An x-ray microscope with a zone plate was assembled at the synchrotron radiation source of BL3C, Photon Factory. A Foucault knife-edge was set at the back focal plate of the objective zone plate and phase retrieval was tested by scanning the knife-edge. A preliminary result shows that scanning the knife-edge during exposure was effective for phase retrieval. Phase-contrast tomography was investigated using differential projection images calculated from two Schlieren images with the oppositely oriented knife-edges. Fairly good reconstruction images of polystyrene beads and spores could be obtained.

  7. Microwave Microscope

    Data.gov (United States)

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

  8. Observation of banded spherulites and lamellar structures by atomic force microscopy

    Institute of Scientific and Technical Information of China (English)

    姜勇; 罗艳红; 范泽夫; 王霞瑜; 徐军; 郭宝华; 李林

    2003-01-01

    Lamellar structures of banded spherulites of poly(ε-caprolactone)/poly(vinyl chloride) (PCL/PVC) blends are observed using tapping mode atomic force microscopy (AFM). The surface of the PCL/PVC banded spherulites presents to be concentric periodic ups and downs. The period of the bands corresponds to the extinction rings under the polarized optical microscopy observation. The lamellae with edge-on orientation in the ridges and the flat-on lamellae in the valleys of the banded spherulites are observed clearly. The twisting between the edge-on and flat-on lamellae is also observed.

  9. 蛋白质对 PVDF 超滤膜污染行为的界面微观作用力解析%Adhesion Force Analysis of Protein Fouling of PVDF Ultrafiltration Membrane Using Atomic Force Microscope

    Institute of Scientific and Technical Information of China (English)

    王旭东; 周淼; 孟晓荣; 王磊; 黄丹曦; 夏四清

    2015-01-01

    To determine the fouling behavior of bovine serum albumin (BSA) on different hydrophilic PVDF ultrafiltration membrane over a range of pH, atomic force microscopy (AFM) and self-made colloidal probes were used to detect the microscopic adhesion forces of membrane-BSA and BSA-BSA, respectively. The results showed a positive correlation between the flux decline extent and the membrane-foulant adhesion force in the initial filtration stage, whereas the foulant-foulant interaction force was closely related to the membrane fouling in the later filtration stage. Moreover, the membrane-BSA adhesion interaction was stronger than the BSA-BSA adhesion interaction, which indicated that the fouling was mainly caused by the adhesion interaction between membrane and foulant. At the same pH, the adhesion force between PA membrane-BSA was smaller than that of PP membrane-BSA, illustrating the more hydrophilic the membrane was, the better the antifouling ability it had. The adhesion force between BSA-BSA fouled PA membrane was similar to that between BSA-BSA fouled PP membrane. These results confirmed that elimination of the membrane-BSA adhesion force is important to control the protein fouling of membranes.%采用原子力显微镜,结合自制微颗粒探针,对膜-污染物及污染物-污染物间微观作用力进行了检测分析,考察了不同 pH条件下牛血清蛋白(BSA)在不同界面特性 PVDF 超滤膜上的膜污染行为。结果表明,在膜过滤初期,通量剧烈衰减主要由 BSA和膜之间黏附力作用导致,在膜过滤后期,BSA 与 BSA 之间的黏聚作用则是影响后期膜污染行为的主要因素; PA 膜-BSA 和PP 膜-BSA 之间的黏附作用力均大于 BSA-BSA 之间的黏聚作用力,说明在整个膜过滤过程中,BSA 与 PVDF 超滤膜之间的黏附作用对膜污染起主导作用;相同 pH 条件下,PA 膜-BSA 之间的微观作用小于 PP 膜-BSA 之间的相互作用力,说明亲水性较强的 PA 膜具

  10. Flow structures in submarine channels affected by Coriolis forces: Experimental observations

    Science.gov (United States)

    Cossu, R.; Wells, M. G.

    2011-12-01

    In this talk we will show how Coriolis forces can control the flow dynamics of turbidity currents flowing in sinuous channels at high latitudes. We describe how the internal velocity structure changes with latitude, based on observations from rotating laboratory experiments. When these results are combined with existing conceptual facies and depositional models we can now describe the changes in sedimentation patterns that are observed at different latitudes. The experiments were conducted in a sinuous channel model placed in a tank that was rotated at various rates (reflected by the Coriolis parameters f) ranging from f = 0 (at the equator) to ± 0.5 rad s-1 (at higher latitudes). The dependence of the density interface of gravity currents on rotation is shown in Figure 1a. At the equator the interface slopes up to the outer bend due to the centrifugal forces. In the Northern Hemisphere (NH) the tilt of the interface increases as now the Coriolis forces reinforce the centrifugal acceleration. In contrast, in the Southern Hemisphere (SH) the current ramps up to the inner bend and Coriolis forces dominate over centrifugal forces. Figure 1b shows the corresponding position of the downstream velocity core in the bend apex. At the equator the core is predominantly close to the centerline, whilst in the NH the core is deflected to the inner bend and in the SH the velocity core is shifted to the outer bank. Based upon our experimental results, we hypothesize that Coriolis forces can affect the velocity structure and sedimentation regime. Lateral accretion packages (LAPs) are built only on one side in the channel and finer sediments will be deposited mainly on the levee bank to which the high velocity core is deflected. The Rossby number RoW = U/fW (where U is the mean downstream velocity and W the channel width) can be used to determine the influence of Coriolis forces. In channel systems at high-latitudes (with RoW 1 implying that Coriolis forces are negligible. LAPs

  11. Tropospheric Radiative Forcing from EL Chichon and MT. Pinatubo: Theory and Observations

    Science.gov (United States)

    Dutton, Ellsworth George

    1995-01-01

    The possibility of volcanic effects on global and regional climate variables has had a long history of speculation, correlative study, and proposed physical mechanisms. The potential for widespread surface cooling following the extensive spreading of long-lived stratospheric aerosols following major volcanic eruptions is based on the partial blocking of solar radiation incident at the top of the troposphere. Relatively simple physical mechanisms oppose this potential for cooling: dominant forward solar scattering and absorption of outgoing infrared radiation by the aerosols. More complex considerations are the spatial and temporal variations of the distributed aerosol and its optical and physical properties; potential for water/ice cloud modification by the volcanic particles; surface albedo, water vapor, and cloud feedbacks to a temperature change; the role of the oceans in a large-scale radiatively forced temperature variation; possible circulation modifications; and other forced and random variations in climate. In the current work, rigorous radiative transfer calculations relative to a subset of the above considerations are carried out and compared to observational data to examine deterministic volcanic effects on climate. Specifically, zonally resolved volcanic radiative forcing at the tropopause, and other levels, is computed from the best available information on the spatial and temporal distribution of volcanic aerosols from two recent eruptions, El Chichon (Mexico, 1982) and Mt. Pinatubo (Philippines, 1991). Accuracy of the radiative calculations is partially verified with surface- and satellite -based irradiance observations. Maximum global seasonal -mean radiative forcings of -4.5 and -2.2 W m^{-2} are calculated following the Mt. Pinatubo and El Chichon eruptions, respectively. Within hemisphere irradiance gradient anomalies of up to 16% at the tropopause are calculated for the second N. Hemisphere summer following the eruptions. The computed radiative

  12. Study of a prototypical convective boundary layer observed during BLLAST: contributions by large-scale forcings

    Directory of Open Access Journals (Sweden)

    H. Pietersen

    2014-07-01

    Full Text Available We study the disturbances of CBL dynamics due to large-scale atmospheric contributions for a representative day observed during the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST campaign. We first reproduce the observed boundary-layer dynamics by combining the Dutch Atmospheric Large-Eddy Simulation (DALES model with a mixed-layer theory based model. We find that by only taking surface and entrainment fluxes into account, the boundary-layer height is overestimated by 70%. If we constrain our numerical experiments with the BLLAST comprehensive data set, we are able to quantify the contributions of advection of heat and moisture, and subsidence. We find that subsidence has a clear diurnal pattern. Supported by the presence of a nearby mountain range, this pattern suggests that not only synoptic scales exert their influence on the boundary layer, but also mesoscale circulations. Finally, we study whether the vertical and temporal evolution of turbulent variables are influenced by these large-scale forcings. Our model results show good correspondence of the vertical structure of turbulent variables with observations. Our findings further indicate that when large-scale advection and subsidence are applied, the values for turbulent kinetic are lower than without these large-scale forcings. We conclude that the prototypical CBL can still be used as a valid representation of the boundary-layer dynamics near regions characterized by complex topography and small-scale surface heterogeneity, provided that surface- and large-scale forcings are well characterized.

  13. New aspects of the structure of human hair on the basis of optical microscopic observations of disassembled hair parts.

    Science.gov (United States)

    Yamauchi, Asao; Yamauchi, Kiyoshi

    2015-01-01

    Infant' and adult' scalp hair fibers were disassembled to various cellular components and blocks by chemical and enzymatic treatments, followed by random scission with rapidly rotating cutters. The hair fibers were also fractured by the use of a vise. The optical microscopic inspection of these specimens led to the discovery of many previously unknown structures in the hair shaft. In particular, a cuticular cell (Cu) was found to take a trowel-like shape consisting of a part with a blade-like shape (CuB) and a part with a handle-like shape (CuH), where CuB overlapped one another and fused partially to build the honeycomb-like structure on a large cuticular thin plate (CuP). Whereas CuH was closely similar to the cortical cell in dimensions and richness of macrofibrils (Mf). It was considered that human hair is stabilized structurally and physicochemically by the presence of the honeycomb-like structure, the CuP and the Mf.

  14. Traction Control of Electric Vehicles Using Sliding-Mode Controller with Tractive Force Observer

    Directory of Open Access Journals (Sweden)

    Suwat Kuntanapreeda

    2014-01-01

    Full Text Available Traction control is an important element in modern vehicles to enhance drive efficiency, safety, and stability. Traction is produced by friction between tire and road, which is a nonlinear function of wheel slip. In this paper, a sliding-mode control approach is used to design a robust traction controller. The control objective is to operate vehicles such that a desired wheel slip ratio is achieved. A nonlinearity observer is employed to estimate tire tractive forces, which are used in the control law. Simulation and experimental results have illustrated the success of the proposed observer-based controller.

  15. The role of surface corrugation and tip oscillation in single-molecule manipulation with a non-contact atomic force microscope

    Directory of Open Access Journals (Sweden)

    Christian Wagner

    2014-02-01

    Full Text Available Scanning probe microscopy (SPM plays an important role in the investigation of molecular adsorption. The possibility to probe the molecule–surface interaction while tuning its strength through SPM tip-induced single-molecule manipulation has particularly promising potential to yield new insights. We recently reported experiments, in which 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA molecules were lifted with a qPlus-sensor and analyzed these experiments by using force-field simulations. Irrespective of the good agreement between the experiment and those simulations, systematic inconsistencies remained that we attribute to effects omitted from the initial model. Here we develop a more realistic simulation of single-molecule manipulation by non-contact AFM that includes the atomic surface corrugation, the tip elasticity, and the tip oscillation amplitude. In short, we simulate a full tip oscillation cycle at each step of the manipulation process and calculate the frequency shift by solving the equation of motion of the tip. The new model correctly reproduces previously unexplained key features of the experiment, and facilitates a better understanding of the mechanics of single-molecular junctions. Our simulations reveal that the surface corrugation adds a positive frequency shift to the measurement that generates an apparent repulsive force. Furthermore, we demonstrate that the scatter observed in the experimental data points is related to the sliding of the molecule across the surface.

  16. Switching fields of high-resolution magnetic force microscope tips coated with Co, Co75Pt10Cr15, Co75Pt25, and Co50Pt50 films

    Directory of Open Access Journals (Sweden)

    Ishihara Shinji

    2014-07-01

    Full Text Available Magnetic force microscope (MFM tips are prepared by coating Si tips of 4 nm radius with Co, Co75Pt10Cr15, Co75Pt25, and Co50Pt50 (at. % films of 20 nm thickness at 300 °C. The effects of coating film material on the spatial resolution and the switching field are investigated. Higher resolutions are observed in the order of Co75Pt10Cr15 < (Co50Pt50, Co75Pt25 < Co. The Co-coated tip shows the highest resolution of 7.3 nm, which seems to be depending on a high detection sensitivity related with the magnetic moment of Co material. The saturation magnetization increases in the order of Co75Pt10Cr15 < Co50Pt50 < Co75Pt25 < Co. Higher switching fields are observed in the order of Co < Co75Pt10Cr15 < Co75Pt25 < Co50Pt50. The Co50Pt50-coated tip shows the highest switching field of 1.675±0.025 kOe, which is due to a high coercive field of the magnetic film involving L11 ordered phase with high magnetocrystalline anisotropy energy. The coercive field is recognized in the order of Co < Co75Pt10Cr15 < Co75Pt25 < Co50Pt50. A tip prepared by coating Co50Pt50 film which has high resolution and high switching field is useful for MFM observations of high-density recording media and permanent magnets.

  17. Explanation for the Transverse Radiation Force Observed on a Vertically Hanging Fiber

    CERN Document Server

    Brevik, Iver

    2014-01-01

    As shown in the experiment of She {\\it et al.} [Phys. Rev. Lett. {\\bf 101}, 243601 (2008)], a weak laser beam sent through a vertically hanging fiber exerts a transverse force and produces a lateral displacement of the fiber's lower end. The experiment is of obvious theoretical interest in connection with the electromagnetic theory of media. Suggested explanations given for this effect in the past include the famous Abraham-Minkowski issue concerning the "correct" photon momentum in matter. In our opinion such an explanation can hardly be right. Instead, we propose instead a very simple description of the effect implying that the sideways deflection is caused by the radiation force on the {\\it obliquely cut} lower end face of the fiber. From a calculation based upon geometrical optics, we find quite good agreement with the observations. We present also, as an alternative approach, a calculation involving wave optics instead of geometrical optics, and find comparable results.

  18. Observation of Intrinsic Magnus Force and Direct Detection of Chirality in Superfluid 3He-A

    Science.gov (United States)

    Ikegami, Hiroki; Tsutsumi, Yasumasa; Kono, Kimitoshi

    2015-04-01

    We report details of the observation of the intrinsic Magnus (IM) force acting on negative and positive ions trapped just below a free surface of the A phase of superfluid 3He (3He-A). From the transport measurements of the ions along the surface, we found that the IM force acts on both the negative and positive ions. We also demonstrate that the transport measurements could distinguish whether the surface is composed of a chiral monodomain or multiple chiral domains. For multiple chiral domains, the current of the ions was found to be irreproducible and unstable, which was reasonably explained by the formation of the chiral domain structure and the dynamics of the chiral domain walls. For chiral monodomains, the appearance ratio of chirality emerging upon cooling through the superfluid transition temperature was found to depend on the direction of the external magnetic field, which implies the existence of an unknown coupling between the chirality and the magnetic field.

  19. Observation and numerical experiments for drag coefficient under typhoon wind forcing

    Science.gov (United States)

    Cao, Huiqiu; Zhou, Liangming; Li, Shuiqing; Wang, Zhifeng

    2017-02-01

    This paper presents a study on drag coefficients under typhoon wind forcing based on observations and numerical experiments. The friction velocity and wind speed are measured at a marine observation platform in the South China Sea. Three typhoons: SOULIK (2013), TRAMI (2013) and FITOW (2013) are observed at a buoy station in the northeast sea area of Pingtan Island. A new parameterization is formulated for the wind drag coefficient as a function of wind speed. It is found that the drag coefficient ( C d ) increases linearly with the slope of 0.083×10-3 for wind speed less than 24 m s-1. To investigate the drag coefficient under higher wind conditions, three numerical experiments are implemented for these three typhoons using SWAN wave model. The wind input data are objective reanalysis datasets, which are assimilated with many sources and provided every six hours with the resolution of 0.125°×0.125°. The numerical simulation results show a good agreement with wave observation data under typhoon wind forcing. The results indicate that the drag coefficient levels off with the linear slope of 0.012×10-3 for higher wind speeds (less than 34 m s-1) and the new parameterization improvese the simulation accuracy compared with the Wu (1982) default used in SWAN.

  20. Observational determination of surface radiative forcing by CO2 from 2000 to 2010

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, Daniel R.; Collins, William D.; Gero, P. Johnathan; Torn, Margaret S.; Mlawer, Eli J.; Shippert, Timothy R.

    2015-02-25

    The climatic impact of CO2 and other greenhouse gases is usually quantified in terms of radiative forcing1, calculated as the difference between estimates of the Earth’s radiation field from pre-industrial and present-day concentrations of these gases. Radiative transfer models calculate that the increase in CO2 since 1750 corresponds to a global annual-mean radiative forcing at the tropopause of 1.82 ± 0.19 W m-2 (ref. 2). However, despite widespread scientific discussion and modelling of the climate impacts of well-mixed greenhouse gases, there is little direct observational evidence of the radiative impact of increasing atmospheric CO2. Here we present observationally based evidence of clear-sky CO2 surface radiative forcing that is directly attributable to the increase, between 2000 and 2010, of 22 parts per million atmospheric CO2. The time series of this forcing at the two locations—the Southern Great Plains and the North Slope of Alaska—are derived from Atmospheric Emitted Radiance Interferometer spectra3 together with ancillary measurements and thoroughly corroborated radiative transfer calculations4. The time series both show statistically significant trends of 0.2 W m-2 per decade (with respective uncertainties of ±0.06 W m-2 per decade and ±0.07 W m-2 per decade) and have seasonal ranges of 0.1–0.2 W m-2. This is approximately ten per cent of the trend in downwelling longwave radiation5, 6, 7. These results confirm theoretical predictions of the atmospheric greenhouse effect due to anthropogenic emissions, and provide empirical evidence of how rising CO2 levels, mediated by temporal variations due to photosynthesis and respiration, are affecting the surface energy balance.

  1. 原子力显微镜对常用7种单克隆抗体形态的观察%Morphologies of seven commonly used monoclonal antibodies under atomic force microscope

    Institute of Scientific and Technical Information of China (English)

    侯永微; 纪小龙; 王美娥

    2013-01-01

    Objective To lay the foundation for establishing a morphological structure database of commonly used antibodies by studying the morphology of antigen-antibody reaction under atomic forced microscope. Methods Seven antibodies were added onto slides and placed into a wet kit containing 10%neutral buffer formalin. One hour after the antibodies were kept in an incubator at 37℃, they were washed with distilled water and dried. Their morphologies were observed under atomic force microscope. The width, maximum height and mean roughness of particles were measured. Results The long rod cytokeratin and S100 protein muse anti-human monoclonal antibodies, the oblate round common antigens of vimentin and leukocyte as well as cytokeratin 7 and Dog-1 mouse antihuman monoclonal antibodies, and the triangle thyroglobulin monoclonal antibodies were observed in 2D figures. The width and maximum height of monoclonal antibodies were significantly different (P0.05). Conclusion The morphologies of 7 monoclonal antibodies can be divided into long rod, oblate round and triangle types, which directly prove the relative specificity of antibodies and can thus provide the morphological foundation for further studying the co-expression and exceptional expression of antigens.%  目的为抗原抗体反应提供原子力显微镜下的形态学基础,为建立常用抗体形态结构的形态库打下基础。方法将7种常用单克隆抗体分别滴加于载玻片上,放入加有10%中性缓冲甲醛的湿盒内,置于37℃温箱中1 h,用蒸馏水轻轻涮洗,晾干,用原子力显微镜(atomic force microscope,AFM)进行扫描,观察形态,测量扫描颗粒的宽度、最大峰高度和平均粗糙度。结果在2D图中,细胞角蛋白(广谱)、S100蛋白鼠抗人单克隆抗体为长杆状,波形蛋白、白细胞共同抗原、细胞角蛋白7、Dog-1鼠抗人单克隆抗体为类圆形,甲状腺球蛋白鼠抗人单克隆抗体为三角形;不同组间

  2. Observational evidence for temporary planetary wave forcing of the MLT during fall equinox

    CERN Document Server

    Stray, Nora H; Espy, Patrick J; Hibbins, Robert E

    2016-01-01

    We present direct observations of zonal wave numbers 1 and 2 planetary wave activity in the mesopause region derived from a longitudinal chain of high-latitude Northern Hemisphere (51-66$^{\\circ}$N) Super Dual Auroral Radar Network radars. Over a 9 year period (2000-2008), the planetary wave activity observed shows a consistent increase around the fall equinox. This is shown to be coincident with a minimum in the magnitude of the stratospheric winds and consequently a minimum in the stratospheric gravity wave filtering and the subsequent momentum deposition in the mesopause region. Despite this, the observed meridional winds are shown to be perturbed poleward and mesopause temperatures rise temporarily, suggesting that westward momentum deposition from planetary waves temporarily becomes the dominant forcing on the mesopause region each fall equinox.

  3. Observation of nuclear track in organic material by atomic force microscopy in real time during etching

    CERN Document Server

    Palmino, F; Labrune, J C

    1999-01-01

    The developments of Atomic Force Microscopy (AFM) allow to investigated solid surfaces with a nanometer scale. These techniques are useful methods allowing direct observation of surface morphologies. Particularly in the nuclear track fields, they offer a new tool to give many new informations on track formation. In this paper we present the preliminary results of a new use of this technique to characterize continuously the formation of the revealed track in a cellulose nitrate detector (LR115) after an alpha particle irradiation. For that, a specific cell has been used to observe, by nano-observations, the evolution of track shapes simultaneously with chemical treatment. Thus, the track shape evolution has been studied; visualizing the evolution of the tracks in real time, in situ during the chemical etching process.

  4. Martian Microscope

    Science.gov (United States)

    2004-01-01

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

  5. Microscopic colitis

    DEFF Research Database (Denmark)

    Münch, A; Aust, D; Bohr, Jakob

    2012-01-01

    Microscopic colitis (MC) is an inflammatory bowel disease presenting with chronic, non-bloody watery diarrhoea and few or no endoscopic abnormalities. The histological examination reveals mainly two subtypes of MC, lymphocytic or collagenous colitis. Despite the fact that the incidence in MC has...... been rising over the last decades, research has been sparse and our knowledge about MC remains limited. Specialists in the field have initiated the European Microscopic Colitis Group (EMCG) with the primary goal to create awareness on MC. The EMCG is furthermore a forum with the intention to promote...

  6. Martian Microscope

    Science.gov (United States)

    2004-01-01

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

  7. Field and material stresses predict observable surface forces in optical and electrostatic manipulation

    Science.gov (United States)

    Kemp, Brandon A.; Sheppard, Cheyenne J.

    2016-09-01

    The momentum of light in media has been one of the most debated topics in physics over the past one hundred years. Originally a theoretical debate over the electrodynamics of moving media, practical applications have emerged over the past few decades due to interest in optical manipulation and nanotechnology. Resolution of the debate identifies a kinetic momentum as the momentum of the fields responsible for center of mass translations and a canonical momentum related to the coupled field and material system. The optical momentum resolution has been considered incomplete because it did not uniquely identify the full stress-energy-momentum (SEM) tensor of the field-kinetic subsystem. A consequence of this partial resolution is that the field-kinetic momentum could be described by three of the leading formulations found in the literature. The Abraham, Einstein-Laub, and Chu SEM tensors share the field-kinetic momentum, but their SEM tensors differ resulting in competing force densities. We can show now that the Abraham and Einstein-Laub formulations are invalid since their SEM tensors are not frame invariant, whereas the Chu SEM tensor satisfies relativistic principles as the field-kinetic formulation. However, a number of reports indicate that the force distribution in matter may not accurately represent experimental observations. In this correspondence, we show that the field-kinetic SEM tensor can be used along with the corresponding material subsystem to accurately predict experimental force and stress distributions. We model experimental examples from optical and static manipulation of particles and fluids.

  8. In situ direct observation of photocorrosion in ZnO crystals in ionic liquid using a laser-equipped high-voltage electron microscope

    Directory of Open Access Journals (Sweden)

    J. Ishioka

    2017-03-01

    Full Text Available ZnO photocatalysts in water react with environmental water molecules and corrode under illumination. ZnO nanorods in water can also grow because of water splitting induced by UV irradiation. To investigate their morphological behavior caused by crystal growth and corrosion, here we developed a new laser-equipped high-voltage electron microscope and observed crystal ZnO nanorods immersed in ionic liquid. Exposing the specimen holder to a laser with a wavelength of 325 nm, we observed the photocorrosion in situ at the atomic scale for the first time. This experiment revealed that Zn and O atoms near the interface between the ZnO nanorods and the ionic liquid tended to dissolve into the liquid. The polarity and facet of the nanorods were strongly related to photocorrosion and crystal growth.

  9. In situ observation on hydrogenation of Mg-Ni films using environmental transmission electron microscope with aberration correction

    Science.gov (United States)

    Matsuda, Junko; Yoshida, Kenta; Sasaki, Yukichi; Uchiyama, Naoki; Akiba, Etsuo

    2014-08-01

    In situ transmission electron microscopy (TEM) was performed to observe the hydrogenation of Mg-Ni films in a hydrogen atmosphere of 80-100 Pa. An aberration-corrected environmental TEM with a differential pumping system allows us to reveal the Angstrom-scale structure of the films in the initial stage of hydrogenation: first, nucleation and growth of Mg2NiH4 crystals with a lattice spacing of 0.22 nm in an Mg-rich amorphous matrix of the film occurs within 20 s after the start of the high-resolution observation, then crystallization of MgH2 with a smaller spacing of 0.15 nm happens after approximately 1 min. Our in situ TEM method is also applicable to the analysis of other hydrogen-related materials.

  10. Microscopic colitis.

    Science.gov (United States)

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

    2012-11-21

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

  11. Microscopic colitis

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  12. Electron microscopic observations and DNA chain fragmentation studies on apoptosis in bone tumor cells induced by 153Sm—EDTMP

    Institute of Scientific and Technical Information of China (English)

    ZhuShou-Peng; XiaoDong; 等

    1997-01-01

    The morphological changes observed by electron microscopy indicate that after internal irradiation with 153Sm-ESTMP bone tumor cells displayed feature of apoptosis,such as margination of condensed chromatin,chromatin fragmentation.as well as the membranebouded apoptotic bodies formation.THe quantification analysis of fragmentation DNA for bone tumor cells induced by 153Sm-EDTMP shows that the DNA fragmentation is enhanced with the prolongation of internally irradiated time.These characteristics suggest that 153Sm-EDTMP internal irradiation could induce bone tumor cells to go9 to apoptosis.

  13. Observation of multicellular spinning behavior of Proteus mirabilis by atomic force microscopy and multifunctional microscopy.

    Science.gov (United States)

    Liu, Yanxia; Deng, Yuanxin; Luo, Shuxiu; Deng, Yu; Guo, Linming; Xu, Weiwei; Liu, Lei; Liu, Junkang

    2014-01-01

    This study aimed to observe the multicellular spinning behavior of Proteus mirabilis by atomic force microscopy (AFM) and multifunctional microscopy in order to understand the mechanism underlying this spinning movement and its biological significance. Multifunctional microscopy with charge-coupled device (CCD) and real-time AFM showed changes in cell structure and shape of P. mirabilis during multicellular spinning movement. Specifically, the morphological characteristics of P. mirabilis, multicellular spinning dynamics, and unique movement were observed. Our findings indicate that the multicellular spinning behavior of P. mirabilis may be used to collect nutrients, perform colonization, and squeeze out competitors. The movement characteristics of P. mirabilis are vital to the organism's biological adaptability to the surrounding environment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Transmission electron microscopic observations of acrosome and head abnormalities in impala (Aepyceros melampus sperm from the Kruger National Park

    Directory of Open Access Journals (Sweden)

    D.J. Ackerman

    1997-01-01

    Full Text Available Sperm morphological features play an important role in semen evaluation. Exposure to a variety of chemical compounds, especially environmental endocrine disrupters, elicit abnormalities in sperm of certain species. Baseline data on ultrastructure of normal sperm as well as abnormalities observed concomitantly, are required before causal links between such substances and abnormalities can be established. Live spermatozoa were collected from the cauda epididymis of 64 impala rams in the Kruger National Park and studied by transmission electron microscopy to document normal sperm features and abnormalities. The following abnormalities of the acrosome and sperm head were documented from micrographs: Loose acrosome in various stages of disintegration, lip forming of the acrosome; bizarre head, crater defect, poor condensation of the nucleus and the Dag defect. The observed abnormalities were very similar to those reported for other members of the Bovidae. Different forms of a hollow sphere, formed by the nucleus and covered by an abnormal acrosome have not previously been described for other species.

  15. A new myxozoan parasite from the Amazonian fish Metynnis argenteus (Teleostei, Characidae): light and electron microscope observations.

    Science.gov (United States)

    Casal, Graça; Matos, Edilson; Azevedo, Carlos

    2006-08-01

    Myxobolus metynnis n. sp. (Phylum Myxozoa) is described in the connective subcutaneous tissues of the orbicular region of the fish, Metynnis argenteus (Characidae), collected in the lower Amazon River, near the city of Peixe Boi, Pará State, Brazil. Polysporic, histozoic plasmodia were delimited by a double membrane with numerous microvilli on the peripheral cytoplasm. Several life-cycle stages, including mature spores, were observed. An envelope formed by numerous fine and anastomosed microfibrils was observed at the spore surface. The spore body presented an ellipsoidal shape and was about 13.1 microm long, 7.8 microm wide, and 3.9 microm thick. Elongated-pyriform polar capsules were of equal size, measuring 5.2 microm in length, 3.2 microm in width, and possessing a polar filament with 8-9 turns around the longitudinal axis. The binucleated sporoplasm contained a vacuole and numerous sporoplasmosomes. These were circular in cross-section, showing an adherent eccentric, dense structure, with a half-crescent section. Based on the morphological differences and host specificity, we propose that the parasite is a new species named Myxobolus metynnis n. sp.

  16. A four-alternative forced choice (4AFC) software for observer performance evaluation in radiology

    Science.gov (United States)

    Zhang, Guozhi; Cockmartin, Lesley; Bosmans, Hilde

    2016-03-01

    Four-alternative forced choice (4AFC) test is a psychophysical method that can be adopted for observer performance evaluation in radiological studies. While the concept of this method is well established, difficulties to handle large image data, perform unbiased sampling, and keep track of the choice made by the observer have restricted its application in practice. In this work, we propose an easy-to-use software that can help perform 4AFC tests with DICOM images. The software suits for any experimental design that follows the 4AFC approach. It has a powerful image viewing system that favorably simulates the clinical reading environment. The graphical interface allows the observer to adjust various viewing parameters and perform the selection with very simple operations. The sampling process involved in 4AFC as well as the speed and accuracy of the choice made by the observer is precisely monitored in the background and can be easily exported for test analysis. The software has also a defensive mechanism for data management and operation control that minimizes the possibility of mistakes from user during the test. This software can largely facilitate the use of 4AFC approach in radiological observer studies and is expected to have widespread applicability.

  17. Microscopic colitis: a review.

    Science.gov (United States)

    Farrukh, A; Mayberry, J F

    2014-12-01

    In recent years, microscopic colitis has been increasingly diagnosed. This review was carried out to evaluate demographic factors for microscopic colitis and to perform a systematic assessment of available treatment options. Relevant publications up to December 2013 were identified following searches of PubMed and Google Scholar using the key words 'microscopic colitis', 'collagenous colitis' and 'lymphocytic colitis'. Two-hundred and forty-eight articles were identified. The term microscopic colitis includes lymphocytic colitis and collagenous colitis. Both have common clinical symptoms but are well defined histopathologically. The clinical course is usually benign, but serious complications, including death, may occur. A peak incidence from 60 to 70 years of age with a female preponderance is observed. Although most cases are idiopathic, associations with autoimmune disorders, such as coeliac disease and hypothyroidism, as well as with exposure to nonsteroidal anti-inflammatory drugs and proton-pump inhibitors, have been observed. The incidence and prevalence of microscopic colitis is rising and good-quality epidemiological research is needed. Treatment is currently largely based on anecdotal evidence and on results from limited clinical trials of budesonide. Long-term follow-up of these patients is not well established. The review synthesizes work on the definition of microscopic colitis and the relationship between collagenous and lymphocytic colitis. It reviews the international epidemiology and work on aetiology. In addition, it critically considers the efficacy of a range of treatments. Colorectal Disease © 2014 The Association of Coloproctology of Great Britain and Ireland.

  18. Confocal laser scanning microscopic observation on adult Schistosoma japonicum harbored in mice following treatment with single-dose mefloquine.

    Science.gov (United States)

    Xiao, Shu-Hua; Sun, Jun; Xue, Jian

    2012-06-01

    desquamation of gut epithelial cells. As to the reproductive organs, the testes of male worms revealed in reduction of size, decrease in number of germinative cells, and some of them showed degeneration and collapse, or destruction of the capsule around the testis. In female worms, some ovaries only showed degenerated and collapsed cells accompanied with many cell fragments. Meanwhile, almost all of the vitelline cells lost their definition, which revealed in indistinct cell structure, fusion of some cells, and formation of many cell fragments due to their collapse. Fourteen days post-treatment, only some male worms survived the treatment were collected. Their tegument and musculature showed prominent recovery, but severe damage to the gut and testes was still observed. Our results confirm that under the observation by CLSM, mefloquine exhibits destructive effect on adult S. japonicum, particularly the morphological structure of digestive system and reproductive system of the worms.

  19. Magneto-frictional Modeling of Coronal Nonlinear Force-free Fields. II. Application to Observations

    Science.gov (United States)

    Guo, Y.; Xia, C.; Keppens, R.

    2016-09-01

    A magneto-frictional module has been implemented and tested in the Message Passing Interface Adaptive Mesh Refinement Versatile Advection Code (MPI-AMRVAC) in the first paper of this series. Here, we apply the magneto-frictional method to observations to demonstrate its applicability in both Cartesian and spherical coordinates, and in uniform and block-adaptive octree grids. We first reconstruct a nonlinear force-free field (NLFFF) on a uniform grid of 1803 cells in Cartesian coordinates, with boundary conditions provided by the vector magnetic field observed by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) at 06:00 UT on 2010 November 11 in active region NOAA 11123. The reconstructed NLFFF successfully reproduces the sheared and twisted field lines and magnetic null points. Next, we adopt a three-level block-adaptive grid to model the same active region with a higher spatial resolution on the bottom boundary and a coarser treatment of regions higher up. The force-free and divergence-free metrics obtained are comparable to the run with a uniform grid, and the reconstructed field topology is also very similar. Finally, a group of active regions, including NOAA 11401, 11402, 11405, and 11407, observed at 03:00 UT on 2012 January 23 by SDO/HMI is modeled with a five-level block-adaptive grid in spherical coordinates, where we reach a local resolution of 0\\buildrel{\\circ}\\over{.} 06 pixel-1 in an area of 790 Mm × 604 Mm. Local high spatial resolution and a large field of view in NLFFF modeling can be achieved simultaneously in parallel and block-adaptive magneto-frictional relaxations.

  20. A Student-Built Scanning Tunneling Microscope

    Science.gov (United States)

    Ekkens, Tom

    2015-01-01

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

  1. A Student-Built Scanning Tunneling Microscope

    Science.gov (United States)

    Ekkens, Tom

    2015-01-01

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

  2. Direct observation of electronic-liquid-crystal phase transitions and their microscopic origin in La1/3Ca2/3MnO3

    Science.gov (United States)

    Tao, J.; Sun, K.; Yin, W.-G.; Wu, L.; Xin, H.; Wen, J. G.; Luo, W.; Pennycook, S. J.; Tranquada, J. M.; Zhu, Y.

    2016-11-01

    The ground-state electronic order in doped manganites is frequently associated with a lattice modulation, contributing to their many interesting properties. However, measuring the thermal evolution of the lattice superstructure with reciprocal-space probes alone can lead to ambiguous results with competing interpretations. Here we provide direct observations of the evolution of the superstructure in La1/3Ca2/3MnO3 in real space, as well as reciprocal space, using transmission electron microscopic (TEM) techniques. We show that the transitions are the consequence of a proliferation of dislocations plus electronic phase separation. The resulting states are well described by the symmetries associated with electronic-liquid-crystal (ELC) phases. Moreover, our results resolve the long-standing controversy over the origin of the incommensurate superstructure and suggest a new structural model that is consistent with recent theoretical calculations.

  3. Repeatability of measurements: Non-Hermitian observables and quantum Coriolis force

    Science.gov (United States)

    Gardas, Bartłomiej; Deffner, Sebastian; Saxena, Avadh

    2016-08-01

    A noncommuting measurement transfers, via the apparatus, information encoded in a system's state to the external "observer." Classical measurements determine properties of physical objects. In the quantum realm, the very same notion restricts the recording process to orthogonal states as only those are distinguishable by measurements. Therefore, even a possibility to describe physical reality by means of non-Hermitian operators should volens nolens be excluded as their eigenstates are not orthogonal. Here, we show that non-Hermitian operators with real spectra can be treated within the standard framework of quantum mechanics. Furthermore, we propose a quantum canonical transformation that maps Hermitian systems onto non-Hermitian ones. Similar to classical inertial forces this map is accompanied by an energetic cost, pinning the system on the unitary path.

  4. Observation of Ferroelectricity in a Confined Crystallite Using Electron Backscattered Diffraction and Piezoresponse Force Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, P. [Lehigh University, Bethlehem, PA; Jain, H. [Lehigh University, Bethlehem, PA; Williams, D. B. [Lehigh University, Bethlehem, PA; Kalinin, Sergei V [ORNL; Shin, Junsoo [ORNL; Jesse, Stephen [ORNL; Baddorf, Arthur P [ORNL

    2005-01-01

    LaBGeO{sub 5} is a model transparent ferroelectric glass-ceramic (TFGC) material, developed as an inexpensive alternative to single-crystal nonlinear optical materials. The optical activity of the TFGC originates from the ferroelectric phase which remains under a hydrostatic pressure exerted by the surrounding glass matrix. A combination of two techniques, electron-backscattered diffraction (EBSD) and piezoresponse force microscopy (PFM), is employed to monitor the development of the ferroelectric phase. A method is proposed to theoretically construct PFM amplitude maps from EBSD orientation maps. The theoretical vertical piezoresponse map is compared with the experimental piezoresponse map from PFM. A good correlation between the theoretical and experimental maps is observed.

  5. Direct observation of defect structure in protein crystals by atomic force and transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Devaud, G. (Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States)); Furcinitti, P.S. (Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado 80309 (United States)); Fleming, J.C.; Lyon, M.K.; Douglas, K. (Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States))

    1992-09-01

    We have examined the structure of S-layers isolated from {ital Sulfolobus} {ital acidocaldarius} using atomic force microscopy (AFM) and transmission electron microscopy (TEM). From the AFM images, we were able to directly observe individual dimers of the crystal, defects in the crystal structure, and twin boundaries. We have identified two types of boundaries, one defined by a mirror plane and the other by a glide plane. This work shows that twin boundaries are highly structured regions that are directly related to the organization of units within each crystal domain. Projection maps from TEM images have shown that there are significant differences in the final average maps, depending on which side of the sample is adsorbed to the carbon support film. Comparison of AFM images to TEM projection maps has allowed us to relate high magnification views obtained by AFM to the relatively high resolution information obtained by electron microscopy and image processing.

  6. Surface aerosol radiative forcing derived from collocated ground-based radiometric observations during PRIDE, SAFARI, and ACE-Asia.

    Science.gov (United States)

    Hansell, Richard A; Tsay, Si-Chee; Ji, Qiang; Liou, K N; Ou, Szu-Cheng

    2003-09-20

    An approach is presented to estimate the surface aerosol radiative forcing by use of collocated cloud-screened narrowband spectral and thermal-offset-corrected radiometric observations during the Puerto Rico Dust Experiment 2000, South African Fire Atmosphere Research Initiative (SAFARI) 2000, and Aerosol Characterization Experiment-Asia 2001. We show that aerosol optical depths from the Multiple-Filter Rotating Shadowband Radiometer data match closely with those from the Cimel sunphotometer data for two SAFARI-2000 dates. The observed aerosol radiative forcings were interpreted on the basis of results from the Fu-Liou radiative transfer model, and, in some cases, cross checked with satellite-derived forcing parameters. Values of the aerosol radiative forcing and forcing efficiency, which quantifies the sensitivity of the surface fluxes to the aerosol optical depth, were generated on the basis of a differential technique for all three campaigns, and their scientific significance is discussed.

  7. Surface river plume in a large lake under wind forcing: Observations and laboratory experiments

    Science.gov (United States)

    Demchenko, Natalia; He, Cheng; Rao, Yerubandi R.; Valipour, Reza

    2017-10-01

    Observations of a small riverine plume (Grand River, ON) in the nearshore zones of Lake Erie were analyzed to describe its spatial variability and its thickness under different wind forcing conditions during late spring of 2012. Observational results reveal a well-marked frontal region in the vicinity of the river mouth, causing the plume to discharge into the lake in the surface layers (positive buoyant). Wind driven alongshore currents at the mid-depth had speeds of 2-9 cm/s, in comparison to those in the cross-shore 3-6 cm/s, which transported the plume along the shore during the measurement period. Series of laboratory experiments were conducted to obtain the propagation speed (U) of the buoyant plume in terms of buoyancy anomaly (Ba), Richardson number (Ri), dimensionless time (t‧), and aspect ratio (A). Based on our experiments, we developed two non-dimensional relationships describing the speed of propagation (U) as U/Ba1/2 = 8 Ri-1/2t‧1/3A and the plume thickness (h) as h/H = 0.8 Ri-1/4t‧1/2A in the water depth (H), which are in agreement with field observations.

  8. Microscopic observations of sonoporation mechanisms

    Science.gov (United States)

    Zeghimi, Aya; Escoffre, Jean-Michel; Bouakaz, Ayache

    2017-03-01

    Background Sonoporation promises a local gene/drug delivery with a high therapeutic efficacy and low toxicity level. However, the mechanisms orchestrating the molecules uptake are still unclear. Here, we investigate the effects of sonoporation on the plasma membrane of U-87 MG cells, either immediately or at different times post-sonoporation, using electron microscopy, and also the implication of cytoskeleton during the sonoporation process. Methods In our set-up, the U-87 MG cells were seeded on 18 mm diameter cover slips, placed in 24-well plates. The acoustic exposure conditions consisted of ultrasound pulses at 1 MHz, 1W/cm2 with duty cycle of 20% for 60 seconds. BR14® microbubbles were added to the cell medium before sonoporation at a microbubble/cell ratio of 5. These acoustic parameters were obtained as a result of a prior optimization experiments. Membrane permeabilization after sonoporation was assessed using SYTOX® Green dye (1 µM), as a model drug which does not cross the membrane of normal cells. The cell mortality was measured with propidium iodide staining. The alterations, on the plasma membrane, after sonoporation were monitored by scanning electron microscopy (SEM). The cell samples were processed immediately (0 min) and every 5 min up to 60 min post-sonoporation and coated by platinum sputtering (5 nm). For immunofluorescence experiments, the cells were fixed with 4% paraformaldehyde, and then incubated with TRITC-labeled Phalloidin, used to stain the actin cytoskeleton. Tubulin antibody Alexa Fluor® 555 conjugate was used to label the microtubules. Results Our results showed that immediately after ultrasound and microbubble exposure, dark and spherical structures appear on the plasma membrane. These structures have a diameter ranging from few nanometers to 160 nm. These structures are transient, since 15 min post-sonoporation, almost half of these structures disappeared. The decrease in the number of permeant structures is accentuated over time to be fully resorbed 60 min post-sonoporation, consequently the cells still metabolically active. Moreover, flow cytometry results show a positive correlation between membrane permeabilization and the number of these electron dense structures. Indeed, 60% of SYTOX® Green incorporation is achieved immediately after sonoporation, to decay over time and therefore as a function of the presence of these permeant structures on the cell membrane. These structures are named here "permeation structures". To define the nature of the TPS structures the cells were treated with Genistein, an inhibitor of caveolae-mediated endocytosis. Scanning Electron microscopy images showed a significant diminution of the number of TPS for cells incubated with Genistein, suggesting that a large part of these structures are caveolae still open. Moreover, immunofluorescence analysis showed a depolymerization of actin and tubulin cytoskeleton, immediately after sonoporation. This depolymerization is accompanied with a massive uptake of SYTOX® Green, while the use of cytochalasin D and nocodazole (inhibitors of actin and tubulin polymerization) induced a decrease in the percentage of SYTOX® Green incorporation. Conclusion In conclusion, our findings reveal the reversibility of sonoporation effects on the cell membrane, and show that the caveolae-mediated endocytosis is a dominant pathway involved in the sonoporation process of U-87 MG cells, with a probable involvement of other endocytic and non-endocytic pathways. Otherwise, the study of sonoporation on cytoskeleton gives evidence on the involvement of endocytosis during the sonoporation process (entry and transport of molecules).

  9. In situ observations of shape evolution during copper dissolution using atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cruickshank, B.J.; Gewirth, A.A.; Rynders, R.M.; Alkire, R.C. (Illinois Univ., Urbana, IL (United States). Materials Research Lab.)

    1992-10-01

    In this paper, atomic force microscopy is used to monitor, in situ, the shape evolution of polycrystalline copper during anodic dissolution in 0. 5 M H[sub 2]SO[sub 4]. During dissolution of the copper surface under a small anodic potential (30 mV), an overlayer of material that resulted from mechanical polishing was removed, exposing the underlying grain boundaries. A chemically etched sample was exposed to the same experimental conditions, and no overlayer was observed. Dissolution of the copper bulk metal was monitored under a higher applied potential (100 mV, 0. 5M H[sub 2]SO[sub 4]). The overlayer was immediately removed, and the dissolution produced a nonuniform, crystallographically etched surface. The inhibiting effect of benzotriazole (BTA) on copper dissolution in 0. 5M H[sub 2]SO[sub 4]/20 mM BTA was observed. Copper dissolution did not proceed at 100 mV or 200 mV applied potential; but at 300 mV, rapid localized dissolution resulted in the formation of pit-like features.

  10. Observation of reduction in Casimir force without change of dielectric permittivity

    CERN Document Server

    Banishev, A A; Castillo-Garza, R; Klimchitskaya, G L; Mostepanenko, V M; Mohideen, U

    2012-01-01

    Additional information is provided on the effect of the significant (up to 35%) reduction in the magnitude of the Casimir force between an Au-coated sphere and an indium tin oxide film which was observed after UV treatment of the latter. A striking feature of this effect is that the reduction is not accompanied with a corresponding variation of the dielectric permittivity, as confirmed by direct ellipsometry measurements. The measurement data are compared with computations using the Lifshitz theory. It is shown that the data for the untreated sample are in a very good agreement with theory taking into account the free charge carriers in the indium tin oxide. The data for the UV-treated sample exclude the theoretical results obtained with account of free charge carriers. These data are found to be in a very good agreement with theory disregarding the free charge carriers in an indium tin oxide film. A possible theoretical explanation of our observations as a result of phase transition of indium tin oxide from ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Jungk, T.

    2006-12-15

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

  12. Initiation and recovery processes of endotoxin induced disseminated intravascular coagulation (DIC: scanning and transmission electron microscopic observations of rat renal tissues.

    Directory of Open Access Journals (Sweden)

    Miyashima,Takanao

    1989-04-01

    Full Text Available To clarify the initiation, development and recovery processes of disseminated intravascular coagulation (DIC, rat glomerular capillaries and fibrin thrombi were examined under transmission and scanning electron microscopes. DIC was induced in rats by a single intraperitoneal injection of endotoxin (Et., 7.5 mg/kg lipopolysaccharide:B, E. coli 026:B6. At 2 h after Et. injection, the endothelial surface of the glomerular capillary became irregular with projections like a sea anemone. At 4 h after Et. injection, agglomerated fibrin thrombi composed of fibrin fiber bundles with fine cross-striated fibriform structures were observed in the capillary lumen. The fibrin thrombi gradually changed into fine reticular systems suggesting a degradation process by 6 h after Et. injection, and formed a coarse granular agglomerate by 8 h after Et. injection. These fibrin thrombi disappeared within 12 h of Et. injection, but the endothelial surface remained edematous. At 24 h after Et. injection, the microstructure of the glomerular capillaries returned normal. Based on these observations, we concluded that DIC was primarily initiated by injury to the capillary endothelium, and that changes on the endothelial surface contributed to the development of DIC.

  13. An entomopathogenic strain of Beauveria bassiana against Frankliniella occidentalis with no detrimental effect on the predatory mite Neoseiulus barkeri: evidence from laboratory bioassay and scanning electron microscopic observation.

    Directory of Open Access Journals (Sweden)

    Shengyong Wu

    Full Text Available Among 28 isolates of Beauveria bassiana tested for virulence against F. occidentalis in laboratory bioassays, we found strain SZ-26 as the most potent, causing 96% mortality in adults at 1×10(7 mL(-1conidia after 4 days. The effect of the strain SZ-26 on survival, longevity and fecundity of the predatory mite Neoseiulus (Amblyseius barkeri Hughes were studied under laboratory conditions. The bioassay results showed that the corrected mortalities were less than 4 and 8% at 10 days following inoculation of the adult and the larvae of the predator, respectively, with 1×10(7 conidia mL(-1 of SZ-26. Furthermore, no fungal hyphae were found in dead predators. The oviposition and postoviposition durations, longevity, and fecundity displayed no significant differences after inoculation with SZ-26 using first-instar larvae of F. occidentalis as prey in comparison with untreated predator. In contrast, the preoviposition durations were significantly longer. Observations with a scanning electron microscope, revealed that many conidia were attached to the cuticles of F. occidentalis at 2 h after treatment with germ tubes oriented toward cuticle at 24 h, penetration of the insect cuticle at 36 h, and finally, fungal colonization of the whole insect body at 60 h. In contrast, we never observed penetration of the predator's cuticle and conidia were shed gradually from the body, further demonstrating that B. bassiana strain SZ-26 show high toxicity against F. occidentalis but no pathogenicity to predatory mite.

  14. Modelled radiative forcing of the direct aerosol effect with multi-observation evaluation

    Directory of Open Access Journals (Sweden)

    G. Myhre

    2009-02-01

    Full Text Available A high-resolution global aerosol model (Oslo CTM2 driven by meteorological data and allowing a comparison with a variety of aerosol observations is used to simulate radiative forcing (RF of the direct aerosol effect. The model simulates all main aerosol components, including several secondary components such as nitrate and secondary organic carbon. The model reproduces the main chemical composition and size features observed during large aerosol campaigns. Although the chemical composition compares best with ground-based measurement over land for modelled sulphate, no systematic differences are found for other compounds. The modelled aerosol optical depth (AOD is compared to remote sensed data from AERONET ground and MODIS and MISR satellite retrievals. To gain confidence in the aerosol modelling, we have tested its ability to reproduce daily variability in the aerosol content, and this is performing well in many regions; however, we also identified some locations where model improvements are needed. The annual mean regional pattern of AOD from the aerosol model is broadly similar to the AERONET and the satellite retrievals (mostly within 10–20%. We notice a significant improvement from MODIS Collection 4 to Collection 5 compared to AERONET data. Satellite derived estimates of aerosol radiative effect over ocean for clear sky conditions differs significantly on regional scales (almost up to a factor two, but also in the global mean. The Oslo CTM2 has an aerosol radiative effect close to the mean of the satellite derived estimates. We derive a radiative forcing (RF of the direct aerosol effect of −0.35 Wm−2 in our base case. Implementation of a simple approach to consider internal black carbon (BC mixture results in a total RF of −0.28 Wm−2. Our results highlight the importance of carbonaceous particles, producing stronger individual RF than considered in the recent IPCC estimate; however, net RF is less different

  15. Radiative forcing of the direct aerosol effect using a multi-observation approach

    Directory of Open Access Journals (Sweden)

    G. Myhre

    2008-07-01

    Full Text Available A high-resolution global aerosol model (Oslo CTM2 driven by meteorological data and allowing a comparison with a variety of aerosol observations is used to simulate radiative forcing (RF of the direct aerosol effect. The model simulates all main aerosol components, including several secondary components such as nitrate and secondary organic carbon. The model reproduces the main chemical composition and size features observed during large aerosol campaigns. Although the chemical composition compares best with ground-based measurement over land for modelled sulphate, no systematic differences are found for other compounds. The modelled aerosol optical depth (AOD is compared to remote sensed data from AERONET ground and MODIS and MISR satellite retrievals. To gain confidence in the aerosol modelling, we have tested its ability to reproduce daily variability in the aerosol content, and this is performing well in many regions; however, we also identified some locations where model improvements are needed. The annual mean regional pattern of AOD from the aerosol model is broadly similar to the AERONET and the satellite retrievals (mostly within 10–20%. We notice a significant improvement from MODIS Collection 4 to Collection 5 compared to AERONET data. Satellite derived estimates of aerosol radiative effect over ocean for clear sky conditions differs significantly on regional scales (almost up to a factor two, but also in the global mean. The Oslo CTM2 has an aerosol radiative effect close to the mean of the satellite derived estimates. We derive a radiative forcing (RF of the direct aerosol effect of −0.35 Wm−2 in our base case. Implementation of a simple approach to consider internal black carbon (BC mixture results in a total RF of −0.28 Wm−2. Our results highlight the importance of carbonaceous particles, producing stronger individual RF than considered in the recent IPCC estimate; however, net RF is less different

  16. Leveraging Observations of Security Force Assistance in Afghanistan for Global Operations

    Science.gov (United States)

    2013-01-01

    Force Assistance SFAB Security Force Assistance brigade SFAT Security Force Assistance Team SME subject-matter expert STT Security Transition Team...Total Interviewees General SFAT 8 8 STT 1 group interview 7 AWG OA 6 6 GSU SFAT 1 group interview 3 CS SFAT 1 1 CSS SFAT 2 group interviews 14...NOTE: STT = Security Transition Team. OA = Operational Advisor. GSU = garrison support unit. CS = combat support. CSS = combat service support. ANA

  17. Coffee Cup Atomic Force Microscopy

    Science.gov (United States)

    Ashkenaz, David E.; Hall, W. Paige; Haynes, Christy L.; Hicks, Erin M.; McFarland, Adam D.; Sherry, Leif J.; Stuart, Douglas A.; Wheeler, Korin E.; Yonzon, Chanda R.; Zhao, Jing; Godwin, Hilary A.; Van Duyne, Richard P.

    2010-01-01

    In this activity, students use a model created from a coffee cup or cardstock cutout to explore the working principle of an atomic force microscope (AFM). Students manipulate a model of an AFM, using it to examine various objects to retrieve topographic data and then graph and interpret results. The students observe that movement of the AFM…

  18. Coffee Cup Atomic Force Microscopy

    Science.gov (United States)

    Ashkenaz, David E.; Hall, W. Paige; Haynes, Christy L.; Hicks, Erin M.; McFarland, Adam D.; Sherry, Leif J.; Stuart, Douglas A.; Wheeler, Korin E.; Yonzon, Chanda R.; Zhao, Jing; Godwin, Hilary A.; Van Duyne, Richard P.

    2010-01-01

    In this activity, students use a model created from a coffee cup or cardstock cutout to explore the working principle of an atomic force microscope (AFM). Students manipulate a model of an AFM, using it to examine various objects to retrieve topographic data and then graph and interpret results. The students observe that movement of the AFM…

  19. A potential large and persistent black carbon forcing over Northern Pacific inferred from satellite observations

    Science.gov (United States)

    Li, Zhongshu; Liu, Junfeng; Mauzerall, Denise L.; Li, Xiaoyuan; Fan, Songmiao; Horowitz, Larry W.; He, Cenlin; Yi, Kan; Tao, Shu

    2017-03-01

    Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurate estimation of BC’s climate effect is limited by the uncertainties of its spatiotemporal distribution, especially over remote oceanic areas. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 intercepted multiple snapshots of BC profiles over Pacific in various seasons, and revealed a 2 to 5 times overestimate of BC by current global models. In this study, we compared the measurements from aircraft campaigns and satellites, and found a robust association between BC concentrations and satellite-retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R2 > 0.8). This establishes a basis to construct a satellite-based column BC approximation (sBC*) over remote oceans. The inferred sBC* shows that Asian outflows in spring bring much more BC aerosols to the mid-Pacific than those occurring in other seasons. In addition, inter-annual variability of sBC* is seen over the Northern Pacific, with abundances varying consistently with the springtime Pacific/North American (PNA) index. Our sBC* dataset infers a widespread overestimation of BC loadings and BC Direct Radiative Forcing by current models over North Pacific, which further suggests that large uncertainties exist on aerosol-climate interactions over other remote oceanic areas beyond Pacific.

  20. A potential large and persistent black carbon forcing over Northern Pacific inferred from satellite observations

    Science.gov (United States)

    Li, Zhongshu; Liu, Junfeng; Mauzerall, Denise L.; Li, Xiaoyuan; Fan, Songmiao; Horowitz, Larry W.; He, Cenlin; Yi, Kan; Tao, Shu

    2017-01-01

    Black carbon (BC) aerosol strongly absorbs solar radiation, which warms climate. However, accurate estimation of BC’s climate effect is limited by the uncertainties of its spatiotemporal distribution, especially over remote oceanic areas. The HIAPER Pole-to-Pole Observation (HIPPO) program from 2009 to 2011 intercepted multiple snapshots of BC profiles over Pacific in various seasons, and revealed a 2 to 5 times overestimate of BC by current global models. In this study, we compared the measurements from aircraft campaigns and satellites, and found a robust association between BC concentrations and satellite-retrieved CO, tropospheric NO2, and aerosol optical depth (AOD) (R2 > 0.8). This establishes a basis to construct a satellite-based column BC approximation (sBC*) over remote oceans. The inferred sBC* shows that Asian outflows in spring bring much more BC aerosols to the mid-Pacific than those occurring in other seasons. In addition, inter-annual variability of sBC* is seen over the Northern Pacific, with abundances varying consistently with the springtime Pacific/North American (PNA) index. Our sBC* dataset infers a widespread overestimation of BC loadings and BC Direct Radiative Forcing by current models over North Pacific, which further suggests that large uncertainties exist on aerosol-climate interactions over other remote oceanic areas beyond Pacific. PMID:28266532