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Sample records for scanning tip cantilever

  1. 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.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  3. Scanning probe microscopy with vertically oriented cantilevers made easy

    International Nuclear Information System (INIS)

    Valdrè, G; Moro, D; Ulian, G

    2012-01-01

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

  4. Nonlinear dynamic response of cantilever beam tip during atomic force microscopy (AFM) nanolithography of copper surface

    International Nuclear Information System (INIS)

    Yeh, Y-L; Jang, M-J; Wang, C-C; Lin, Y-P; Chen, K-S

    2008-01-01

    This paper investigates the nonlinear dynamic response of an atomic force microscope (AFM) cantilever beam tip during the nanolithography of a copper (Cu) surface using a high-depth feed. The dynamic motion of the tip is modeled using a combined approach based on Newton's law and empirical observations. The cutting force is determined from experimental observations of the piling height on the Cu surface and the rotation angle of the cantilever beam tip. It is found that the piling height increases linearly with the cantilever beam carrier velocity. Furthermore, the cantilever beam tip is found to execute a saw tooth motion. Both this motion and the shear cutting force are nonlinear. The elastic modulus in the y direction is variable. Finally, the velocity of the cantilever beam tip as it traverses the specimen surface has a discrete characteristic rather than a smooth, continuous profile

  5. Force Measurement with a Piezoelectric Cantilever in a Scanning Force Microscope

    OpenAIRE

    Tansock, J.; Williams, C. C.

    1992-01-01

    Detection of surface forces between a tip and sample has been demonstrated with a piezoelectric cantilever in a scanning force microscope (SFM). The use of piezoelectric force sensing is particularly advantageous in semiconductor applications where stray light from conventional optical force-sensing methods can significantly modify the local carrier density. Additionally, the piezoelectric sensors are simple, provide good sensitivity to force, and can be batch fabricated. Our piezoelectric fo...

  6. Nanobits: customizable scanning probe tips

    DEFF Research Database (Denmark)

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

    2009-01-01

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

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

    Science.gov (United States)

    Kan, Tetsuo; Matsumoto, Kiyoshi; Shimoyama, Isao

    2007-08-01

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

  8. Influence of tip mass on dynamic behavior of cracked cantilever pipe conveying fluid with moving mass

    International Nuclear Information System (INIS)

    Yoon, Han Ik; Son, In Soo

    2005-01-01

    In this paper, we studied about the effect of the open crack and a tip mass on the dynamic behavior of a cantilever pipe conveying fluid with a moving mass. The equation of motion is derived by using Lagrange's equation and analyzed by numerical method. The cantilever pipe is modelled by the Euler-Bernoulli beam theory. The crack section is represented by a local flexibility matrix connecting two undamaged pipe segments. The influences of the crack, the moving mass, the tip mass and its moment of inertia, the velocity of fluid, and the coupling of these factors on the vibration mode, the frequency, and the tip-displacement of the cantilever pipe are analytically clarified

  9. Accurate measurement of Atomic Force Microscope cantilever deflection excluding tip-surface contact with application to force calibration

    Energy Technology Data Exchange (ETDEWEB)

    Slattery, Ashley D.; Blanch, Adam J.; Quinton, Jamie S.; Gibson, Christopher T., E-mail: christopher.gibson@flinders.edu.au

    2013-08-15

    Considerable attention has been given to the calibration of AFM cantilever spring constants in the last 20 years. Techniques that do not require tip-sample contact are considered advantageous since the imaging tip is not at risk of being damaged. Far less attention has been directed toward measuring the cantilever deflection or sensitivity, despite the fact that the primary means of determining this factor relies on the AFM tip being pressed against a hard surface, such as silicon or sapphire; which has the potential to significantly damage the tip. A recent method developed by Tourek et al. in 2010 involves deflecting the AFM cantilever a known distance from the imaging tip by pressing the cantilever against a sharpened tungsten wire. In this work a similar yet more precise method is described, whereby the deflection of the cantilever is achieved using an AFM probe with a spring constant much larger than the test cantilever, essentially a rigid cantilever. The exact position of loading on the test cantilever was determined by reverse AFM imaging small spatial markers that are milled into the test cantilever using a focussed ion beam. For V shaped cantilevers it is possible to reverse image the arm intersection in order to determine the exact loading point without necessarily requiring FIB milled spatial markers, albeit at the potential cost of additional uncertainty. The technique is applied to tip-less, beam shaped and V shaped cantilevers and compared to the hard surface contact technique with very good agreement (on average less than 5% difference). While the agreement with the hard surface contact technique was very good the error on the technique is dependent upon the assumptions inherent in the method, such as cantilever shape, loading point distance and ratio of test to rigid cantilever spring constants. The average error ranged between 2 to 5% for the majority of test cantilevers studied. The sensitivity derived with this technique can then be used to

  10. Computerized automatic tip scanning operation

    International Nuclear Information System (INIS)

    Nishikawa, K.; Fukushima, T.; Nakai, H.; Yanagisawa, A.

    1984-01-01

    In BWR nuclear power stations the Traversing Incore Probe (TIP) system is one of the most important components in reactor monitoring and control. In previous TIP systems, however, operators have suffered from the complexity of operation and long operation time required. The system presented in this paper realizes the automatic operation of the TIP system by monitoring and driving it with a process computer. This system significantly reduces the burden on customer operators and improves plant efficiency by simplifying the operating procedure, augmenting the accuracy of the measured data, and shortening operating time. The process computer is one of the PODIA (Plant Operation by Displayed Information Automation) systems. This computer transfers control signals to the TIP control panel, which in turn drives equipment by microprocessor control. The process computer contains such components as the CRT/KB unit, the printer plotter, the hard copier, and the message typers required for efficient man-machine communications. Its operation and interface properties are described

  11. An elastography method based on the scanning contact resonance of a piezoelectric cantilever

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Ji; Li, Faxin, E-mail: lifaxin@pku.edu.cn [State Key Lab for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871, China and HEDPS, Center for Applied Physics and Technologies, Peking University, Beijing 100871 (China)

    2013-12-15

    Purpose: Most tissues may become significantly stiffer than their normal states when there are lesions inside. The tissue's modulus can then act as an identification parameter for clinic diagnosis of tumors or fibrosis, which leads to elastography. This study introduces a novel elastography method that can be used for modulus imaging of superficial organs. Methods: This method is based on the scanning contact-resonance of a unimorph piezoelectric cantilever. The cantilever vibrates in its bending mode with the tip pressed tightly on the sample. The contact resonance frequency of the cantilever-sample system is tracked at each scanning point, from which the sample's modulus can be derived based on a beam dynamic model and a contact mechanics model. Scanning is performed by a three-dimensional motorized stage and the whole system is controlled by a homemade software program based on LabVIEW. Results: Testing onin vitro beef tissues indicates that the fat and the muscle can be easily distinguished using this system, and the accuracy of the modulus measurement can be comparable with that of nanoindentation. Imaging on homemade gelatin phantoms shows that the depth information of the abnormalities can be qualitatively obtained by varying the pressing force. The detection limit of this elastography method is specially examined both experimentally and numerically. Results show that it can detect the typical lesions in superficial organs with the depth of several centimeters. The lateral resolution of this elastography method/system is better than 0.5 mm, and could be further enhanced by using more scanning points. Conclusions: The proposed elastography system can be regarded as a sensitive palpation robot, which may be very promising in early diagnosis of tumors in superficial organs such as breast and thyroid.

  12. An elastography method based on the scanning contact resonance of a piezoelectric cantilever.

    Science.gov (United States)

    Fu, Ji; Li, Faxin

    2013-12-01

    Most tissues may become significantly stiffer than their normal states when there are lesions inside. The tissue's modulus can then act as an identification parameter for clinic diagnosis of tumors or fibrosis, which leads to elastography. This study introduces a novel elastography method that can be used for modulus imaging of superficial organs. This method is based on the scanning contact-resonance of a unimorph piezoelectric cantilever. The cantilever vibrates in its bending mode with the tip pressed tightly on the sample. The contact resonance frequency of the cantilever-sample system is tracked at each scanning point, from which the sample's modulus can be derived based on a beam dynamic model and a contact mechanics model. Scanning is performed by a three-dimensional motorized stage and the whole system is controlled by a homemade software program based on LabVIEW. Testing on in vitro beef tissues indicates that the fat and the muscle can be easily distinguished using this system, and the accuracy of the modulus measurement can be comparable with that of nanoindentation. Imaging on homemade gelatin phantoms shows that the depth information of the abnormalities can be qualitatively obtained by varying the pressing force. The detection limit of this elastography method is specially examined both experimentally and numerically. Results show that it can detect the typical lesions in superficial organs with the depth of several centimeters. The lateral resolution of this elastography method∕system is better than 0.5 mm, and could be further enhanced by using more scanning points. The proposed elastography system can be regarded as a sensitive palpation robot, which may be very promising in early diagnosis of tumors in superficial organs such as breast and thyroid.

  13. Characterization and fabrication of fully metal-coated scanning near-field optical microscopy SiO2 tips.

    Science.gov (United States)

    Aeschimann, L; Akiyama, T; Staufer, U; De Rooij, N F; Thiery, L; Eckert, R; Heinzelmann, H

    2003-03-01

    The fabrication of silicon cantilever-based scanning near-field optical microscope probes with fully aluminium-coated quartz tips was optimized to increase production yield. Different cantilever designs for dynamic- and contact-mode force feedback were implemented. Light transmission through the tips was investigated experimentally in terms of the metal coating and the tip cone-angle. We found that transmittance varies with the skin depth of the metal coating and is inverse to the cone angle, meaning that slender tips showed higher transmission. Near-field optical images of individual fluorescing molecules showed a resolution thermocouple showed no evidence of mechanical defect or orifice formation by thermal effects.

  14. Quantitative analysis of tip-sample interaction in non-contact scanning force spectroscopy

    International Nuclear Information System (INIS)

    Palacios-Lidon, Elisa; Colchero, Jaime

    2006-01-01

    Quantitative characterization of tip-sample interaction in scanning force microscopy is fundamental for optimum image acquisition as well as data interpretation. In this work we discuss how to characterize the electrostatic and van der Waals contribution to tip-sample interaction in non-contact scanning force microscopy precisely. The spectroscopic technique presented is based on the simultaneous measurement of cantilever deflection, oscillation amplitude and frequency shift as a function of tip-sample voltage and tip-sample distance as well as on advanced data processing. Data are acquired at a fixed lateral position as interaction images, with the bias voltage as fast scan, and tip-sample distance as slow scan. Due to the quadratic dependence of the electrostatic interaction with tip-sample voltage the van der Waals force can be separated from the electrostatic force. Using appropriate data processing, the van der Waals interaction, the capacitance and the contact potential can be determined as a function of tip-sample distance. The measurement of resonance frequency shift yields very high signal to noise ratio and the absolute calibration of the measured quantities, while the acquisition of cantilever deflection allows the determination of the tip-sample distance

  15. Cantilever-based optical interfacial force microscope in liquid using an optical-fiber tip

    Directory of Open Access Journals (Sweden)

    Byung I. Kim

    2013-03-01

    Full Text Available We developed a novel cantilever-based optical interfacial force microscope (COIFM to study molecular interaction in liquid environments. The force sensor was created by attaching a chemically etched optical-fiber tip to the force sensor with UV epoxy, and characterized by imaging on a calibration grid. The performance of the COIFM was then demonstrated by measuring the force between two oxidized silicon surfaces in 1 mM KCl as a function of distance. The result was consistent with previously reported electrical double layer forces, suggesting that a COIFM using an optical-fiber tip is capable of measuring force in a liquid environment.

  16. Characterization of metal-coated fiber tip for NSOM lithography by tip-to-tip scan

    International Nuclear Information System (INIS)

    Kubicova, I.; Pudis, D.; Suslik, L.; Skriniarova, J.

    2011-01-01

    For the optical field characterization, a tip-to-tip scan of two metal-coated fiber tips with circular aperture at the apex was performed. The optical field irradiated from the fiber probe in illumination mode was analyzed by NSOM represented by fiber probe in collection mode. The near-field intensity profile of the source fiber tip in the plane perpendicular to the axis of the tip was taken. Experimental stage requires high resolution 3D motion system controlled by computer (Fig. 1). The source and the detector fiber tip were placed on the moving and static part of the 3D nanoposition system, respectively. As a light source, a modulated 473 nm DPSS laser was used. After the source fiber tip characterization, the NSOM lithography was performed. In the experimental setup from Fig. 1, the detector fiber tip was replaced by a sample fixed in a vacuum holder. As a sample, a 600 nm positive photoresist AZ 5214E was spin-coated on a GaAs substrate. Exposure was carried out by irradiation of the sample at desired positions through the fiber tip aperture. The sample was developed in AZ 400K developer for 30 s and rinsed in DI water. A promising tip-to-tip scanning technique for characterization of metal-coated fiber tips with aperture at the apex was presented. Nearly-circular aperture shapes were documented from NSOM measurements with diameter estimated to be less than 460 nm. By knowing the source-detector distance and the FWHM of the near-field intensity profile, the tip-to-tip scan proves an easy and fast method to analyze the fiber tip aperture properties. The fiber tip resolution was confirmed by preparation of 2D planar structures in thin photoresist layer, where the NSOM lithography uses the metal-coated fiber tip characterized in previous section. (authors)

  17. Application of a Cantilevered SWCNT with Mass at the Tip as a Nanomechanical Sensor

    DEFF Research Database (Denmark)

    Mehdipour, I.; Barari, Amin; Domairry, G.

    2011-01-01

    In this paper, the continuum mechanics method and a bending model is applied to obtain the resonant frequency of the fixed-free SWCNT where the mass is rigidly attached to the tip. This method used the Euler–Bernoulli theory with cantilevered boundary conditions where the effect of attached mass ...... of resonant frequency are decreased. The validity and the accuracy of these formulas are examined with other sensor equations in the literatures. The results indicate that the new sensor equations can be used for CNT like CNT-based biosensors with reasonable accuracy....

  18. Discussion of the Improved Methods for Analyzing a Cantilever Beam Carrying a Tip-Mass under Base Excitation

    Directory of Open Access Journals (Sweden)

    Wang Hongjin

    2014-01-01

    Full Text Available Two improved analytical methods of calculations for natural frequencies and mode shapes of a uniform cantilever beam carrying a tip-mass under base excitation are presented based on forced vibration theory and the method of separation of variables, respectively. The cantilever model is simplified in detail by replacing the tip-mass with an equivalent inertial force and inertial moment acting at the free end of the cantilever based on D’Alembert’s principle. The concentrated equivalent inertial force and inertial moment are further represented as distributed loads using Dirac Delta Function. In this case, some typical natural frequencies and mode shapes of the cantilever model are calculated by the improved and unimproved analytical methods. The comparing results show that, after improvement, these two methods are in extremely good agreement with each other even the offset distance between the gravity center of the tip-mass and the attachment point is large. As further verification, the transient and steady displacement responses of the cantilever system under a sine base excitation are presented in which two improved methods are separately utilized. Finally, an experimental cantilever system is fabricated and the theoretical displacement responses are validated by the experimental measurements successfully.

  19. On the dynamics of tapered vibro-impacting cantilever with tip mass

    Energy Technology Data Exchange (ETDEWEB)

    Gandhi, P. S.; Vyas, Vishal [Suman Mashruwala Advanced Microengineering Laboratory, Dept. of Mechanical Engineering, Indian Institute of Technology - Bombay, Mumai (India)

    2017-01-15

    This paper explores nonlinear dynamic behavior of vibro-impacting tapered cantilever with tip mass with regard to frequency response analysis. A typical frequency response curve of vibro-impacting beams displays well-known resonance frequency shift along with a hysteric jump and drop phenomena. We did a comprehensive parametric analysis capturing the effects of taper, tip-mass, stop location, and gap on the non-smooth frequency response. Analysis is presented in a non-dimensional form useful for other similar cases. Simulation results are further validated with corresponding experimental results for a few cases. Illustrative comparison of simulation results for varying parameters brings out several interesting aspects of variation in the nonlinear behavior.

  20. High-speed imaging upgrade for a standard sample scanning atomic force microscope using small cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Jonathan D.; Nievergelt, Adrian; Erickson, Blake W.; Yang, Chen; Dukic, Maja; Fantner, Georg E., E-mail: georg.fantner@epfl.ch [Ecole Polytechnique Fédérale de Lausanne, Lausanne (Switzerland)

    2014-09-15

    We present an atomic force microscope (AFM) head for optical beam deflection on small cantilevers. Our AFM head is designed to be small in size, easily integrated into a commercial AFM system, and has a modular architecture facilitating exchange of the optical and electronic assemblies. We present two different designs for both the optical beam deflection and the electronic readout systems, and evaluate their performance. Using small cantilevers with our AFM head on an otherwise unmodified commercial AFM system, we are able to take tapping mode images approximately 5–10 times faster compared to the same AFM system using large cantilevers. By using additional scanner turnaround resonance compensation and a controller designed for high-speed AFM imaging, we show tapping mode imaging of lipid bilayers at line scan rates of 100–500 Hz for scan areas of several micrometers in size.

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

    Directory of Open Access Journals (Sweden)

    Tobias Meier

    2015-02-01

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

  2. Quantifying Tip-Sample Interactions in Vacuum Using Cantilever-Based Sensors: An Analysis

    Science.gov (United States)

    Dagdeviren, Omur E.; Zhou, Chao; Altman, Eric I.; Schwarz, Udo D.

    2018-04-01

    Atomic force microscopy is an analytical characterization method that is able to image a sample's surface topography at high resolution while simultaneously probing a variety of different sample properties. Such properties include tip-sample interactions, the local measurement of which has gained much popularity in recent years. To this end, either the oscillation frequency or the oscillation amplitude and phase of the vibrating force-sensing cantilever are recorded as a function of tip-sample distance and subsequently converted into quantitative values for the force or interaction potential. Here, we theoretically and experimentally show that the force law obtained from such data acquired under vacuum conditions using the most commonly applied methods may deviate more than previously assumed from the actual interaction when the oscillation amplitude of the probe is of the order of the decay length of the force near the surface, which may result in a non-negligible error if correct absolute values are of importance. Caused by approximations made in the development of the mathematical reconstruction procedures, the related inaccuracies can be effectively suppressed by using oscillation amplitudes sufficiently larger than the decay length. To facilitate efficient data acquisition, we propose a technique that includes modulating the drive amplitude at a constant height from the surface while monitoring the oscillation amplitude and phase. Ultimately, such an amplitude-sweep-based force spectroscopy enables shorter data acquisition times and increased accuracy for quantitative chemical characterization compared to standard approaches that vary the tip-sample distance. An additional advantage is that since no feedback loop is active while executing the amplitude sweep, the force can be consistently recovered deep into the repulsive regime.

  3. Fabrication of wear-resistant silicon microprobe tips for high-speed surface roughness scanning devices

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Yu, Feng; Doering, Lutz; Völlmeke, Stefan; Brand, Uwe; Bakin, Andrey; Waag, Andreas; Peiner, Erwin

    2015-05-01

    Silicon microprobe tips are fabricated and integrated with piezoresistive cantilever sensors for high-speed surface roughness scanning systems. The fabrication steps of the high-aspect-ratio silicon microprobe tips were started with photolithography and wet etching of potassium hydroxide (KOH) resulting in crystal-dependent micropyramids. Subsequently, thin conformal wear-resistant layer coating of aluminum oxide (Al2O3) was demonstrated on the backside of the piezoresistive cantilever free end using atomic layer deposition (ALD) method in a binary reaction sequence with a low thermal process and precursors of trimethyl aluminum and water. The deposited Al2O3 layer had a thickness of 14 nm. The captured atomic force microscopy (AFM) image exhibits a root mean square deviation of 0.65 nm confirming the deposited Al2O3 surface quality. Furthermore, vacuum-evaporated 30-nm/200-nm-thick Au/Cr layers were patterned by lift-off and served as an etch mask for Al2O3 wet etching and in ICP cryogenic dry etching. By using SF6/O2 plasma during inductively coupled plasma (ICP) cryogenic dry etching, micropillar tips were obtained. From the preliminary friction and wear data, the developed silicon cantilever sensor has been successfully used in 100 fast measurements of 5- mm-long standard artifact surface with a speed of 15 mm/s and forces of 60-100 μN. Moreover, the results yielded by the fabricated silicon cantilever sensor are in very good agreement with those of calibrated profilometer. These tactile sensors are targeted for use in high-aspect-ratio microform metrology.

  4. Nanobits - exchangable and customisable scanning probe tips

    DEFF Research Database (Denmark)

    Yildiz, Izzet

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

  5. Modulated photodetection with semiconductor tips in a scanning tunneling microscope

    NARCIS (Netherlands)

    Groeneveld, R.H.M.; Prins, M.W.J.; Kempen, van H.

    1995-01-01

    We report on the detection of modulated light power irradiated into the tunnel junction of a scanning tunneling microscope. When semiconductor tips are used we can distinguish three contributions to the measured current: photocurrent due to electron-hole pair generation at the apex of the tip, a

  6. Regular Scanning Tunneling Microscope Tips can be Intrinsically Chiral

    International Nuclear Information System (INIS)

    Tierney, Heather L.; Murphy, Colin J.; Sykes, E. Charles H.

    2011-01-01

    We report our discovery that regular scanning tunneling microscope tips can themselves be chiral. This chirality leads to differences in electron tunneling efficiencies through left- and right-handed molecules, and, when using the tip to electrically excite molecular rotation, large differences in rotation rate were observed which correlated with molecular chirality. As scanning tunneling microscopy is a widely used technique, this result may have unforeseen consequences for the measurement of asymmetric surface phenomena in a variety of important fields.

  7. Regular scanning tunneling microscope tips can be intrinsically chiral.

    Science.gov (United States)

    Tierney, Heather L; Murphy, Colin J; Sykes, E Charles H

    2011-01-07

    We report our discovery that regular scanning tunneling microscope tips can themselves be chiral. This chirality leads to differences in electron tunneling efficiencies through left- and right-handed molecules, and, when using the tip to electrically excite molecular rotation, large differences in rotation rate were observed which correlated with molecular chirality. As scanning tunneling microscopy is a widely used technique, this result may have unforeseen consequences for the measurement of asymmetric surface phenomena in a variety of important fields.

  8. Bandwidth Widening of Piezoelectric Cantilever Beam Arrays by Mass-Tip Tuning for Low-Frequency Vibration Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Eduard Dechant

    2017-12-01

    Full Text Available Wireless sensor networks usually rely on internal permanent or rechargeable batteries as a power supply, causing high maintenance efforts. An alternative solution is to supply the entire system by harvesting the ambient energy, for example, by transducing ambient vibrations into electric energy by virtue of the piezoelectric effect. The purpose of this paper is to present a simple engineering approach for the bandwidth optimization of vibration energy harvesting systems comprising multiple piezoelectric cantilevers (PECs. The frequency tuning of a particular cantilever is achieved by changing the tip mass. It is shown that the bandwidth enhancement by mass tuning is limited and requires several PECs with close resonance frequencies. At a fixed frequency detuning between subsequent PECs, the achievable bandwidth shows a saturation behavior as a function of the number of cantilevers used. Since the resonance frequency of each PEC is different, the output voltages at a particular excitation frequency have different amplitudes and phases. A simple power-transfer circuit where several PECs with an individual full wave bridge rectifier are connected in parallel allows one to extract the electrical power close to the theoretical maximum excluding the diode losses. The experiments performed on two- and three-PEC arrays show reasonable agreement with simulations and demonstrate that this power-transfer circuit additionally influences the frequency dependence of the harvested electrical power.

  9. Fabrication of silver tips for scanning tunneling microscope induced luminescence.

    Science.gov (United States)

    Zhang, C; Gao, B; Chen, L G; Meng, Q S; Yang, H; Zhang, R; Tao, X; Gao, H Y; Liao, Y; Dong, Z C

    2011-08-01

    We describe a reliable fabrication procedure of silver tips for scanning tunneling microscope (STM) induced luminescence experiments. The tip was first etched electrochemically to yield a sharp cone shape using selected electrolyte solutions and then sputter cleaned in ultrahigh vacuum to remove surface oxidation. The tip status, in particular the tip induced plasmon mode and its emission intensity, can be further tuned through field emission and voltage pulse. The quality of silver tips thus fabricated not only offers atomically resolved STM imaging, but more importantly, also allows us to perform challenging "color" photon mapping with emission spectra taken at each pixel simultaneously during the STM scan under relatively small tunnel currents and relatively short exposure time.

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

    Directory of Open Access Journals (Sweden)

    Tomokazu Sakamoto

    2009-01-01

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

  11. Analytical Model of the Nonlinear Dynamics of Cantilever Tip-Sample Surface Interactions for Various Acoustic-Atomic Force Microscopies

    Science.gov (United States)

    Cantrell, John H., Jr.; Cantrell, Sean A.

    2008-01-01

    A comprehensive analytical model of the interaction of the cantilever tip of the atomic force microscope (AFM) with the sample surface is developed that accounts for the nonlinearity of the tip-surface interaction force. The interaction is modeled as a nonlinear spring coupled at opposite ends to linear springs representing cantilever and sample surface oscillators. The model leads to a pair of coupled nonlinear differential equations that are solved analytically using a standard iteration procedure. Solutions are obtained for the phase and amplitude signals generated by various acoustic-atomic force microscope (A-AFM) techniques including force modulation microscopy, atomic force acoustic microscopy, ultrasonic force microscopy, heterodyne force microscopy, resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM), and the commonly used intermittent contact mode (TappingMode) generally available on AFMs. The solutions are used to obtain a quantitative measure of image contrast resulting from variations in the Young modulus of the sample for the amplitude and phase images generated by the A-AFM techniques. Application of the model to RDF-AFUM and intermittent soft contact phase images of LaRC-cp2 polyimide polymer is discussed. The model predicts variations in the Young modulus of the material of 24 percent from the RDF-AFUM image and 18 percent from the intermittent soft contact image. Both predictions are in good agreement with the literature value of 21 percent obtained from independent, macroscopic measurements of sheet polymer material.

  12. MEMS Tunneling Micro Thermometer Based onTip Deflection of Bimetallic Cantilever Beam

    Directory of Open Access Journals (Sweden)

    Samrand K. Nezhadian

    2007-10-01

    Full Text Available Micro-electro-mechanical (MEM technology promises to significantly reduce the size, weight and cost of a variety of sensor systems. In this article has been described a highly sensitive novel type of thermometer based on deflection of a “bimetallic” microbeam. The proposed thermometer converts the thermal changes of a cantilevered bimetallic beam of submillimeter size into an electrical signal through tunneling-current modulation. The governing thermo-mechanical equation of a bimetallic cantilever beam has been derived and solved analytically. The obtained results show that the proposed tunneling micro thermometer is very sensitive to temperature changes due to exponential increasing of tunneling current but because of small gap between metallic electrodes, measurable range of temperature changes is small.

  13. Application of a LIPCA for the structural vibration suppression of an aluminum cantilever beam with a tip mass

    International Nuclear Information System (INIS)

    Martua, Landong; Heo, Seok; Goo, Nam Seo

    2007-01-01

    Use of bare PZT as an actuator in the field of active vibration suppression may cause some drawbacks such as critical breaks in the installation process, short circuits in the host material and low fatigue performance. To alleviate these problems, we developed a new actuator called a lightweight piezocomposite actuator (LIPCA). The LIPCA has five layers: three glass-epoxy layers, a carbon-epoxy layer and a PZT layer. We implemented a LIPCA as an actuator to suppress the vibration of an aluminum cantilever beam with a tip mass. For the control algorithm in our test, we used positive position feedback. The filter frequency for this type of feedback should be tuned to the frequency of the target mode. The first three experimental natural frequencies of the aluminum cantilever beam agree well with the results of finite element methods. The effectiveness of using a LIPCA as an actuator in active vibration suppression was investigated with respect to the time and frequency domains, and the experimental results show that LIPCAs can significantly reduce the amplitude of forced vibrations as well as the settling time of free vibrations

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-21

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

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

    Science.gov (United States)

    Yacoot, Andrew; Koenders, Ludger

    2008-05-01

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

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

    International Nuclear Information System (INIS)

    Yacoot, Andrew; Koenders, Ludger

    2008-01-01

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

  17. Piezoelectric cantilever sensors

    Science.gov (United States)

    Shih, Wan Y. (Inventor); Shih, Wei-Heng (Inventor); Shen, Zuyan (Inventor)

    2008-01-01

    A piezoelectric cantilever with a non-piezoelectric, or piezoelectric tip useful as mass and viscosity sensors. The change in the cantilever mass can be accurately quantified by monitoring a resonance frequency shift of the cantilever. For bio-detection, antibodies or other specific receptors of target antigens may be immobilized on the cantilever surface, preferably on the non-piezoelectric tip. For chemical detection, high surface-area selective absorbent materials are coated on the cantilever tip. Binding of the target antigens or analytes to the cantilever surface increases the cantilever mass. Detection of target antigens or analytes is achieved by monitoring the cantilever's resonance frequency and determining the resonance frequency shift that is due to the mass of the adsorbed target antigens on the cantilever surface. The use of a piezoelectric unimorph cantilever allows both electrical actuation and electrical sensing. Incorporating a non-piezoelectric tip (14) enhances the sensitivity of the sensor. In addition, the piezoelectric cantilever can withstand damping in highly viscous liquids and can be used as a viscosity sensor in wide viscosity range.

  18. Scanning tip measurement for identification of point defects

    Directory of Open Access Journals (Sweden)

    Raineri Vito

    2011-01-01

    Full Text Available Abstract Self-assembled iron-silicide nanostructures were prepared by reactive deposition epitaxy of Fe onto silicon. Capacitance-voltage, current-voltage, and deep level transient spectroscopy (DLTS were used to measure the electrical properties of Au/silicon Schottky junctions. Spreading resistance and scanning probe capacitance microscopy (SCM were applied to measure local electrical properties. Using a preamplifier the sensitivity of DLTS was increased satisfactorily to measure transients of the scanning tip semiconductor junction. In the Fe-deposited area, Fe-related defects dominate the surface layer in about 0.5 μm depth. These defects deteriorated the Schottky junction characteristic. Outside the Fe-deposited area, Fe-related defect concentration was identified in a thin layer near the surface. The defect transients in this area were measured both in macroscopic Schottky junctions and by scanning tip DLTS and were detected by bias modulation frequency dependence in SCM.

  19. Fabrication of tungsten tip for scanning tunneling microscope by the lever principle

    International Nuclear Information System (INIS)

    Wang Yang; Wang Huabin; Chinese Academy of Sciences, Beijing; Gong Jinlong; Zhu Dezhang

    2007-01-01

    A novel experimental setup was designed to fabricate tungsten tips for scanning tunneling microscope (STM), based on simple mechanical lever principle. The equipment can quickly separate the tip from electrolyte to avoid the further etching of the fine-shaped tungsten tip. The setup is advantageous for its simplicity over complex electronic control systems. The use result in scanning electron microscope demonstrates that the radius of the tip can reach 50 nm. The tip was applied to scan the surface of highly-oriented pyrolytic graphite, and the results were satisfactory. It is shown that the tip can be used for the scanning of atomically resolved images. (authors)

  20. Realization of cantilever arrays for parallel proximity imaging

    International Nuclear Information System (INIS)

    Sarov, Y; Ivanov, Tz; Frank, A; Zoellner, J-P; Nikolov, N; Rangelow, I W

    2010-01-01

    This paper reports on the fabrication and characterisation of self-actuating, and self-sensing cantilever arrays for large-scale parallel surface scanning. Each cantilever is integrated with a sharp silicon tip, a thermal-driven bimorph actuator, and a piezoresistive deflection sensor. Thus, the tip to the sample distance can be controlled individually for each cantilever. A radius of the tips below 10 nm is obtained, which enables nanometre in-plane surface imaging by Angstrom resolution in vertical direction. The fabricated cantilever probe arrays are also applicable for large-area manipulation, sub-10 nm metrology, bottom-up synthesis, high-speed gas analysis, for different bio-applications like recognition of DNA, RNA, or various biomarkers of a single disease, etc.

  1. Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips.

    Science.gov (United States)

    Tewari, Sumit; Bastiaans, Koen M; Allan, Milan P; van Ruitenbeek, Jan M

    2017-01-01

    Scanning tunneling microscopes (STM) are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

  2. Towards quantitative determination of the spring constant of a scanning force microscope cantilever with a microelectromechanical nano-force actuator

    International Nuclear Information System (INIS)

    Gao, Sai; Herrmann, Konrad; Zhang, Zhikai; Wu, Yong

    2010-01-01

    The calibration of the performance of an SFM (scanning force microscope) cantilever has gained more and more interest in the past years, particularly due to increasing applications of SFMs for the determination of the mechanical properties of materials, such as biological structures and organic molecules. In this paper, a MEMS-based nano-force actuator with a force resolution up to nN (10 −9 N) is presented to quantitatively determine the stiffness of an SFM cantilever. The principle, structure design and realization of the nano-force actuator are detailed. Preliminary experiments demonstrate that the long-term self-calibration stability of the actuator is better than 3.7 × 10 −3 N m −1 (1σ) over 1 h. With careful calibration of the stiffness of the actuator, the MEMS actuator has the capability to determine the stiffness of various types of cantilevers (from 100 N m −1 down to 0.1 N m −1 ) with high accuracy. In addition, thanks to the large displacement and force range (up to 8 µm and 1 mN, respectively) of the actuator, the calibration procedure with our MEMS nano-force actuator features simple and active operation, and therefore applicability for different types of quantitative SFMs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-03-15

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

  4. Cantilever arrays with self-aligned nanotips of uniform height

    International Nuclear Information System (INIS)

    Koelmans, W W; Peters, T; Berenschot, E; De Boer, M J; Siekman, M H; Abelmann, L

    2012-01-01

    Cantilever arrays are employed to increase the throughput of imaging and manipulation at the nanoscale. We present a fabrication process to construct cantilever arrays with nanotips that show a uniform tip–sample distance. Such uniformity is crucial, because in many applications the cantilevers do not feature individual tip–sample spacing control. Uniform cantilever arrays lead to very similar tip–sample interaction within an array, enable non-contact modes for arrays and give better control over the load force in contact modes. The developed process flow uses a single mask to define both tips and cantilevers. An additional mask is required for the back side etch. The tips are self-aligned in the convex corner at the free end of each cantilever. Although we use standard optical contact lithography, we show that the convex corner can be sharpened to a nanometre scale radius by an isotropic underetch step. The process is robust and wafer-scale. The resonance frequencies of the cantilevers within an array are shown to be highly uniform with a relative standard error of 0.26% or lower. The tip–sample distance within an array of up to ten cantilevers is measured to have a standard error around 10 nm. An imaging demonstration using the AFM shows that all cantilevers in the array have a sharp tip with a radius below 10 nm. The process flow for the cantilever arrays finds application in probe-based nanolithography, probe-based data storage, nanomanufacturing and parallel scanning probe microscopy. (paper)

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

    Science.gov (United States)

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

    2018-04-01

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

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

    Science.gov (United States)

    Goodwin, Eric; Tessmer, Stuart

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

  7. Robust procedure for creating and characterizing the atomic structure of scanning tunneling microscope tips

    Directory of Open Access Journals (Sweden)

    Sumit Tewari

    2017-11-01

    Full Text Available Scanning tunneling microscopes (STM are used extensively for studying and manipulating matter at the atomic scale. In spite of the critical role of the STM tip, procedures for controlling the atomic-scale shape of STM tips have not been rigorously justified. Here, we present a method for preparing tips in situ while ensuring the crystalline structure and a reproducibly prepared tip structure up to the second atomic layer. We demonstrate a controlled evolution of such tips starting from undefined tip shapes.

  8. Design and performance of a beetle-type double-tip scanning tunneling microscope

    International Nuclear Information System (INIS)

    Jaschinsky, Philipp; Coenen, Peter; Pirug, Gerhard; Voigtlaender, Bert

    2006-01-01

    A combination of a double-tip scanning tunneling microscope with a scanning electron microscope in ultrahigh vacuum environment is presented. The compact beetle-type design made it possible to integrate two independently driven scanning tunneling microscopes in a small space. Moreover, an additional level for coarse movement allows the decoupling of the translation and approach of the tunneling tip. The position of the two tips can be controlled from the millimeter scale down to 50 nm with the help of an add-on electron microscope. The instrument is capable of atomic resolution imaging with each tip

  9. In situ scanning tunneling microscope tip treatment device for spin polarization imaging

    Science.gov (United States)

    Li, An-Ping [Oak Ridge, TN; Jianxing, Ma [Oak Ridge, TN; Shen, Jian [Knoxville, TN

    2008-04-22

    A tip treatment device for use in an ultrahigh vacuum in situ scanning tunneling microscope (STM). The device provides spin polarization functionality to new or existing variable temperature STM systems. The tip treatment device readily converts a conventional STM to a spin-polarized tip, and thereby converts a standard STM system into a spin-polarized STM system. The tip treatment device also has functions of tip cleaning and tip flashing a STM tip to high temperature (>2000.degree. C.) in an extremely localized fashion. Tip coating functions can also be carried out, providing the tip sharp end with monolayers of coating materials including magnetic films. The device is also fully compatible with ultrahigh vacuum sample transfer setups.

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

  11. Mechanical characterization of biocompatible thin film materials by scanning along micro-machined cantilevers for micro-/nano-system

    International Nuclear Information System (INIS)

    He, J.H.; Luo, J.K.; Le, H.R.; Moore, D.F.

    2006-01-01

    Mechanical characterization is vital for the design of micro-/nano-electro-mechanical system (MEMS/NEMS). This paper describes a new characterization method to extract the mechanical properties of the thin film materials, which is simple, inexpensive and applicable to a wide range of materials including biocompatible ones described in this paper. The beams of the material under tests, are patterned by laser micro-machining and released by alkaline etch. A surface profilometer is used to scan along micro-machined cantilevers and produce a bending profile, from which the Young's modulus can be extracted. Biocompatible SiN x , SiC and nanocrystal diamond cantilevers have been fabricated and their Young's modulus has been evaluated as 154 ± 12, 360 ± 50 and 504 ± 50 GPa, respectively, which is consistent with those measured by nano-indentation. Residual stress gradient has also been extracted by surface profilometer, which is comparable with the results inferred from ZYGO interferometer measurements. This method can be extended to atomic force microscopy stylus or nanometer-stylus profilometer for Bio-NEMS mechanical characterization

  12. Hard-tip, soft-spring lithography.

    Science.gov (United States)

    Shim, Wooyoung; Braunschweig, Adam B; Liao, Xing; Chai, Jinan; Lim, Jong Kuk; Zheng, Gengfeng; Mirkin, Chad A

    2011-01-27

    Nanofabrication strategies are becoming increasingly expensive and equipment-intensive, and consequently less accessible to researchers. As an alternative, scanning probe lithography has become a popular means of preparing nanoscale structures, in part owing to its relatively low cost and high resolution, and a registration accuracy that exceeds most existing technologies. However, increasing the throughput of cantilever-based scanning probe systems while maintaining their resolution and registration advantages has from the outset been a significant challenge. Even with impressive recent advances in cantilever array design, such arrays tend to be highly specialized for a given application, expensive, and often difficult to implement. It is therefore difficult to imagine commercially viable production methods based on scanning probe systems that rely on conventional cantilevers. Here we describe a low-cost and scalable cantilever-free tip-based nanopatterning method that uses an array of hard silicon tips mounted onto an elastomeric backing. This method-which we term hard-tip, soft-spring lithography-overcomes the throughput problems of cantilever-based scanning probe systems and the resolution limits imposed by the use of elastomeric stamps and tips: it is capable of delivering materials or energy to a surface to create arbitrary patterns of features with sub-50-nm resolution over centimetre-scale areas. We argue that hard-tip, soft-spring lithography is a versatile nanolithography strategy that should be widely adopted by academic and industrial researchers for rapid prototyping applications.

  13. 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...

  14. Tip preparation for usage in an ultra-low temperature UHV scanning tunneling microscope

    Directory of Open Access Journals (Sweden)

    S. Ernst, S. Wirth, M. Rams, V. Dolocan and F. Steglich

    2007-01-01

    Full Text Available This work deals with the preparation and characterization of tungsten tips for the use in UHV low-temperature scanning tunneling microscopy and spectroscopy (STM and STS, respectively. These specific environments require in situ facilities for tip conditioning, for further sharpening of the tips, as well as for reliable tip characterization. The implemented conditioning methods include direct resistive annealing, annealing by electron bombardment, and self-sputtering with noble gas ions. Moreover, results from in situ tip characterization by field emission and STM experiments were compared to ex situ scanning electron microscopy. Using the so-prepared tips, high resolution STM images and tunneling spectra were obtained in a temperature range from ambient down to 350 mK, partially with applied magnetic field, on a variety of materials.

  15. Influence of the tip mass and position on the AFM cantilever dynamics: Coupling between bending, torsion and flexural modes

    Energy Technology Data Exchange (ETDEWEB)

    Mokhtari-Nezhad, F. [Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Saidi, A.R., E-mail: saidi@mail.uk.ac.ir [Department of Mechanical Engineering, Shahid Bahonar University of Kerman, Kerman (Iran, Islamic Republic of); Ziaei-Rad, S. [Department of Mechanical Engineering, Isfahan University of Technology (IUT), Isfahan 84156-83111 (Iran, Islamic Republic of)

    2009-08-15

    The effects of the geometrical asymmetric related to tip position as a concentrated mass, on the sensitivity of all three vibration modes, lateral excitation (LE), torsional resonance (TR) and vertical excitation (VE), of an atomic force microscopy (AFM) microcantilever have been analyzed. The effects of the tip mass and its position are studied to report the novel results to estimating the vibration behavior of AFM such as resonance frequency and amplitude of the microcantilever. In this way, to achieve more accurate results, the coupled motion in all three modes is considered. In particular, it is investigated that performing the coupled motion in analysis of AFM microcantilever is almost necessary. It is shown that the tip mass and its position have significant effects on vibrational responses. The results show that considering the tip mass decreases the resonance frequencies particularly on high-order modes. However, dislocating of tip position has an inverse effect that causes an increase in the resonance frequencies. In addition, it has been shown that the amplitude of the AFM microcantilever is affected by the influences of tip and its position. These effects are caused by the interaction between flexural and torsional motion due to the moment of inertia of the tip mass.

  16. Influence of the tip mass and position on the AFM cantilever dynamics: Coupling between bending, torsion and flexural modes

    International Nuclear Information System (INIS)

    Mokhtari-Nezhad, F.; Saidi, A.R.; Ziaei-Rad, S.

    2009-01-01

    The effects of the geometrical asymmetric related to tip position as a concentrated mass, on the sensitivity of all three vibration modes, lateral excitation (LE), torsional resonance (TR) and vertical excitation (VE), of an atomic force microscopy (AFM) microcantilever have been analyzed. The effects of the tip mass and its position are studied to report the novel results to estimating the vibration behavior of AFM such as resonance frequency and amplitude of the microcantilever. In this way, to achieve more accurate results, the coupled motion in all three modes is considered. In particular, it is investigated that performing the coupled motion in analysis of AFM microcantilever is almost necessary. It is shown that the tip mass and its position have significant effects on vibrational responses. The results show that considering the tip mass decreases the resonance frequencies particularly on high-order modes. However, dislocating of tip position has an inverse effect that causes an increase in the resonance frequencies. In addition, it has been shown that the amplitude of the AFM microcantilever is affected by the influences of tip and its position. These effects are caused by the interaction between flexural and torsional motion due to the moment of inertia of the tip mass.

  17. Preparation of Chemically Etched Tips for Ambient Instructional Scanning Tunneling Microscopy

    Science.gov (United States)

    Zaccardi, Margot J.; Winkelmann, Kurt; Olson, Joel A.

    2010-01-01

    A first-year laboratory experiment that utilizes concepts of electrochemical tip etching for scanning tunneling microscopy (STM) is described. This experiment can be used in conjunction with any STM experiment. Students electrochemically etch gold STM tips using a time-efficient method, which can then be used in an instructional grade STM that…

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  19. Note: Automated electrochemical etching and polishing of silver scanning tunneling microscope tips.

    Science.gov (United States)

    Sasaki, Stephen S; Perdue, Shawn M; Rodriguez Perez, Alejandro; Tallarida, Nicholas; Majors, Julia H; Apkarian, V Ara; Lee, Joonhee

    2013-09-01

    Fabrication of sharp and smooth Ag tips is crucial in optical scanning probe microscope experiments. To ensure reproducible tip profiles, the polishing process is fully automated using a closed-loop laminar flow system to deliver the electrolytic solution to moving electrodes mounted on a motorized translational stage. The repetitive translational motion is controlled precisely on the μm scale with a stepper motor and screw-thread mechanism. The automated setup allows reproducible control over the tip profile and improves smoothness and sharpness of tips (radius 27 ± 18 nm), as measured by ultrafast field emission.

  20. Molecular tips for scanning tunneling microscopy: intermolecular electron tunneling for single-molecule recognition and electronics.

    Science.gov (United States)

    Nishino, Tomoaki

    2014-01-01

    This paper reviews the development of molecular tips for scanning tunneling microscopy (STM). Molecular tips offer many advantages: first is their ability to perform chemically selective imaging because of chemical interactions between the sample and the molecular tip, thus improving a major drawback of conventional STM. Rational design of the molecular tip allows sophisticated chemical recognition; e.g., chiral recognition and selective visualization of atomic defects in carbon nanotubes. Another advantage is that they provide a unique method to quantify electron transfer between single molecules. Understanding such electron transfer is mandatory for the realization of molecular electronics.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-15

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

  3. Variable-temperature independently driven four-tip scanning tunneling microscope

    International Nuclear Information System (INIS)

    Hobara, Rei; Nagamura, Naoka; Hasegawa, Shuji; Matsuda, Iwao; Yamamoto, Yuko; Miyatake, Yutaka; Nagamura, Toshihiko

    2007-01-01

    The authors have developed an ultrahigh vacuum (UHV) variable-temperature four-tip scanning tunneling microscope (STM), operating from room temperature down to 7 K, combined with a scanning electron microscope (SEM). Four STM tips are mechanically and electrically independent and capable of positioning in arbitrary configurations in nanometer precision. An integrated controller system for both of the multitip STM and SEM with a single computer has also been developed, which enables the four tips to operate either for STM imaging independently and for four-point probe (4PP) conductivity measurements cooperatively. Atomic-resolution STM images of graphite were obtained simultaneously by the four tips. Conductivity measurements by 4PP method were also performed at various temperatures with the four tips in square arrangement with direct contact to the sample surface

  4. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    International Nuclear Information System (INIS)

    Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R.

    2015-01-01

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  5. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R., E-mail: dkillelea@luc.edu [Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W. Sheridan Rd., Chicago, Illinois 60660 (United States)

    2015-03-15

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  6. Construction of a four tip scanning tunneling microscope/scanning electron microscope combination and conductivity measurements of silicide nanowires

    International Nuclear Information System (INIS)

    Zubkov, Evgeniy

    2013-01-01

    In this work the combination of a four-tip scanning tunneling microscope with a scanning electron microscope is presented. By means of this apparatus it is possible to perform the conductivity measurements on the in-situ prepared nanostructures in ultra-high vacuum. With the aid of a scanning electron microscope (SEM), it becomes possible to position the tunneling tips of the four-tip scanning tunneling microscope (STM), so that an arrangement for a four-point probe measurement on nanostructures can be obtained. The STM head was built according to the novel coaxial Beetle concept. This concept allows on the one hand, a very compact arrangement of the components of the STM and on the other hand, the new-built STM head has a good mechanical stability, in order to achieve atomic resolution with all four STM units. The atomic resolution of the STM units was confirmed by scanning a Si(111)-7 x 7 surface. The thermal drift during the STM operation, as well as the resonant frequencies of the mechanical structure of the STM head, were determined. The scanning electron microscope allows the precise and safe navigation of the tunneling tips on the sample surface. Multi tip spectroscopy with up to four STM units can be performed synchronously. To demonstrate the capabilities of the new-built apparatus the conductivity measurements were carried out on metallic yttrium silicide nanowires. The nanowires were prepared by the in-situ deposition of yttrium on a heated Si(110) sample surface. Current-voltage curves were recorded on the nanowires and on the wetting layer in-between. The curves indicate an existence of the Schottky barrier between the yttrium silicide nanowires and the silicon bulk. By means of the two-tip measurements with a gate, the insulating property of the Schottky barrier has been confirmed. Using this Schottky barrier, it is possible to limit the current to the nanowire and to prevent it from flowing through the silicon bulk. A four-tip resistance measurement

  7. Three-way flexible cantilever probes for static contact

    DEFF Research Database (Denmark)

    Wang, Fei; Petersen, Dirch Hjorth; Jensen, Helle Vendelbo

    2011-01-01

    In micro four-point probe measurements, three-way flexible L-shaped cantilever probes show significant advantages over conventional straight cantilever probes. The L-shaped cantilever allows static contact to the sample surface which reduces the frictional wear of the cantilever tips. We analyze...

  8. Photoelectrical properties of semiconductor tips in scanning tunneling microscopy

    NARCIS (Netherlands)

    Prins, M.W.J.; Jansen, R.; Groeneveld, R.H.M.; Gelder, Van A.P.; Kempen, van H.

    1996-01-01

    We describe a model as well as experiments on the electrical properties of a photoexcited tunnel junction between a metal and a semiconductor material, as is established in a scanning tunneling microscope. The model treats the case in which carrier transport is mediated by capture and relaxation in

  9. Single-step electrochemical method for producing very sharp Au scanning tunneling microscopy tips

    International Nuclear Information System (INIS)

    Gingery, David; Buehlmann, Philippe

    2007-01-01

    A single-step electrochemical method for making sharp gold scanning tunneling microscopy tips is described. 3.0M NaCl in 1% perchloric acid is compared to several previously reported etchants. The addition of perchloric acid to sodium chloride solutions drastically shortens etching times and is shown by transmission electron microscopy to produce very sharp tips with a mean radius of curvature of 15 nm

  10. Coating of tips for electrochemical scanning tunneling microscopy by means of silicon, magnesium, and tungsten oxides

    Science.gov (United States)

    Salerno, Marco

    2010-09-01

    Different combinations of metal tips and oxide coatings have been tested for possible operation in electrochemical scanning tunneling microscopy. Silicon and magnesium oxides have been thermally evaporated onto gold and platinum-iridium tips, respectively. Two different thickness values have been explored for both materials, namely, 40 and 120 nm for silicon oxide and 20 and 60 nm for magnesium oxide. Alternatively, tungsten oxide has been grown on tungsten tips via electrochemical anodization. In the latter case, to seek optimal results we have varied the pH of the anodizing electrolyte between one and four. The oxide coated tips have been first inspected by means of scanning electron microscopy equipped with microanalysis to determine the morphological results of the coating. Second, the coated tips have been electrically characterized ex situ for stability in time by means of cyclic voltammetry in 1 M aqueous KCl supporting electrolyte, both bare and supplemented with K3[Fe(CN)6] complex at 10 mM concentration in milliQ water as an analyte. Only the tungsten oxide coated tungsten tips have shown stable electrical behavior in the electrolyte. For these tips, the uncoated metal area has been estimated from the electrical current levels, and they have been successfully tested by imaging a gold grating in situ, which provided stable results for several hours. The successful tungsten oxide coating obtained at pH=4 has been assigned to the WO3 form.

  11. Development of a Micro-SPM (Scanning Probe Microscope by Post-Assembly of a MEMS-Stage and an Independent Cantilever

    Directory of Open Access Journals (Sweden)

    Zhi Li

    2007-08-01

    Full Text Available The development of miniature scanning probe microscopes (SPM on the basis of the MEMS technique has gained more and more interest. Here a novel approach is presented to realize a micro-SPM, in which by means of post-assembly a conventional cantilever is mounted onto a MEMS positioning stage and used to detect the topography variation of the surface under test. Compared with other integrated micro-SPMs, the proposed micro-SPM can maintain the lateral resolution by simply renewing its cantilever in use, and therefore features low cost, practicability and longer lifetime. Preliminary experimental results are reported, which demonstrate that the proposed microSPM can be realized.

  12. Tip-Dependent Scanning Tunneling Microscopy Imaging of Ultrathin FeO Films on Pt(111)

    DEFF Research Database (Denmark)

    Merte, Lindsay Richard; Grabow, Lars C.; Peng, Guowen

    2011-01-01

    High-resolution scanning tunneling microscope (STM) images of moiré-structured FeO films on Pt(111) were obtained in a number of different tip-dependent imaging modes. For the first time, the STM images are distinguished and interpreted unambiguously with the help of distinct oxygen...

  13. 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....

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

    Science.gov (United States)

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

    2014-02-21

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

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

    Science.gov (United States)

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

    2012-06-01

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

  16. Calibration of tip and sample temperature of a scanning tunneling microscope using a superconductive sample

    Energy Technology Data Exchange (ETDEWEB)

    Stocker, Matthias; Pfeifer, Holger; Koslowski, Berndt, E-mail: berndt.koslowski@uni-ulm.de [Institute of Solid State Physics, University of Ulm, D-89069 Ulm (Germany)

    2014-05-15

    The temperature of the electrodes is a crucial parameter in virtually all tunneling experiments. The temperature not only controls the thermodynamic state of the electrodes but also causes thermal broadening, which limits the energy resolution. Unfortunately, the construction of many scanning tunneling microscopes inherits a weak thermal link between tip and sample in order to make one side movable. Such, the temperature of that electrode is badly defined. Here, the authors present a procedure to calibrate the tip temperature by very simple means. The authors use a superconducting sample (Nb) and a standard tip made from W. Due to the asymmetry in the density of states of the superconductor (SC)—normal metal (NM) tunneling junction, the SC temperature controls predominantly the density of states while the NM controls the thermal smearing. By numerically simulating the I-V curves and numerically optimizing the tip temperature and the SC gap width, the tip temperature can be accurately deduced if the sample temperature is known or measureable. In our case, the temperature dependence of the SC gap may serve as a temperature sensor, leading to an accurate NM temperature even if the SC temperature is unknown.

  17. Calibration of tip and sample temperature of a scanning tunneling microscope using a superconductive sample

    International Nuclear Information System (INIS)

    Stocker, Matthias; Pfeifer, Holger; Koslowski, Berndt

    2014-01-01

    The temperature of the electrodes is a crucial parameter in virtually all tunneling experiments. The temperature not only controls the thermodynamic state of the electrodes but also causes thermal broadening, which limits the energy resolution. Unfortunately, the construction of many scanning tunneling microscopes inherits a weak thermal link between tip and sample in order to make one side movable. Such, the temperature of that electrode is badly defined. Here, the authors present a procedure to calibrate the tip temperature by very simple means. The authors use a superconducting sample (Nb) and a standard tip made from W. Due to the asymmetry in the density of states of the superconductor (SC)—normal metal (NM) tunneling junction, the SC temperature controls predominantly the density of states while the NM controls the thermal smearing. By numerically simulating the I-V curves and numerically optimizing the tip temperature and the SC gap width, the tip temperature can be accurately deduced if the sample temperature is known or measureable. In our case, the temperature dependence of the SC gap may serve as a temperature sensor, leading to an accurate NM temperature even if the SC temperature is unknown

  18. 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. © 2011 American Institute of Physics

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

  20. A 30 mK, 13.5 T scanning tunneling microscope with two independent tips

    Energy Technology Data Exchange (ETDEWEB)

    Roychowdhury, Anita [Laboratory for Physical Sciences, College Park, Maryland 20742 (United States); Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20740 (United States); Gubrud, M. A.; Dana, R.; Dreyer, M. [Laboratory for Physical Sciences, College Park, Maryland 20742 (United States); Anderson, J. R.; Lobb, C. J.; Wellstood, F. C. [Center for Nanophysics and Advanced Materials, Department of Physics, University of Maryland, College Park, Maryland 20740 (United States)

    2014-04-15

    We describe the design, construction, and performance of an ultra-low temperature, high-field scanning tunneling microscope (STM) with two independent tips. The STM is mounted on a dilution refrigerator and operates at a base temperature of 30 mK with magnetic fields of up to 13.5 T. We focus on the design of the two-tip STM head, as well as the sample transfer mechanism, which allows in situ transfer from an ultra high vacuum preparation chamber while the STM is at 1.5 K. Other design details such as the vibration isolation and rf-filtered wiring are also described. Their effectiveness is demonstrated via spectral current noise characteristics and the root mean square roughness of atomic resolution images. The high-field capability is shown by the magnetic field dependence of the superconducting gap of Cu{sub x}Bi{sub 2}Se{sub 3}. Finally, we present images and spectroscopy taken with superconducting Nb tips with the refrigerator at 35 mK that indicate that the effective temperature of our tips/sample is approximately 184 mK, corresponding to an energy resolution of 16 μeV.

  1. Modeling of Electronic Transport in Scanning Tunneling Microscope Tip-Carbon Nanotube Systems

    Science.gov (United States)

    Yamada, Toshishige; Kwak, Dochan (Technical Monitor)

    2000-01-01

    A model is proposed for two observed current-voltage (I-V) patterns in a recent experiment with a scanning tunneling microscope tip and a carbon nanotube. We claim that there are two mechanical contact modes for a tip (metal) -nanotube (semiconductor) junction (1) with or (2) without a tiny vacuum gap (0.1 - 0.2 nm). With the tip grounded, the tunneling case in (1) would produce large dI/dV with V > 0, small dI/dV with V < 0, and I = 0 near V = 0 for an either n- or p-nanotube; the Schottky mechanism in (2) would result in I does not equal 0 only with V < 0 for an n-nanotube, and the bias polarities would be reversed for a p-nanotube. The two observed I-V patterns are thus entirely explained by a tip-nanotube contact of the two types, where the nanotube must be n-type.

  2. A 30 mK, 13.5 T scanning tunneling microscope with two independent tips.

    Science.gov (United States)

    Roychowdhury, Anita; Gubrud, M A; Dana, R; Anderson, J R; Lobb, C J; Wellstood, F C; Dreyer, M

    2014-04-01

    We describe the design, construction, and performance of an ultra-low temperature, high-field scanning tunneling microscope (STM) with two independent tips. The STM is mounted on a dilution refrigerator and operates at a base temperature of 30 mK with magnetic fields of up to 13.5 T. We focus on the design of the two-tip STM head, as well as the sample transfer mechanism, which allows in situ transfer from an ultra high vacuum preparation chamber while the STM is at 1.5 K. Other design details such as the vibration isolation and rf-filtered wiring are also described. Their effectiveness is demonstrated via spectral current noise characteristics and the root mean square roughness of atomic resolution images. The high-field capability is shown by the magnetic field dependence of the superconducting gap of CuxBi2Se3. Finally, we present images and spectroscopy taken with superconducting Nb tips with the refrigerator at 35 mK that indicate that the effective temperature of our tips/sample is approximately 184 mK, corresponding to an energy resolution of 16 μeV.

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

    International Nuclear Information System (INIS)

    Nicolet, Anaïs; Küng, Alain; Meli, Felix

    2012-01-01

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

  4. Deformation and wear of pyramidal, silicon-nitride AFM tips scanning micrometre-size features in contact mode

    NARCIS (Netherlands)

    Bloo, M.; Haitjema, H.; Pril, W.O.

    1999-01-01

    An experimental study was carried out, in order to investigate the deformation and wear taking place on pyramidal silicon-nitride AFM tips. The study focuses on the contact mode scanning of silicon features of micrometre-size. First the deformation and the mechanisms of wear of the tip during

  5. Cutting efficiency of apical preparation using ultrasonic tips with microprojections: confocal laser scanning microscopy study

    Directory of Open Access Journals (Sweden)

    Sang-Won Kwak

    2014-11-01

    Full Text Available Objectives The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. Materials and Methods The apical 3-mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan or JT-5B (B&L Biotech Ltd.. The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1, J1 (JT-5B / Power-1, K4 (KIS-1D / Power-4, and J4 (JT-5B / Power-4. The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. Results There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05. The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. Conclusions Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency.

  6. Cutting efficiency of apical preparation using ultrasonic tips with microprojections: confocal laser scanning microscopy study.

    Science.gov (United States)

    Kwak, Sang-Won; Moon, Young-Mi; Yoo, Yeon-Jee; Baek, Seung-Ho; Lee, WooCheol; Kim, Hyeon-Cheol

    2014-11-01

    The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. The apical 3-mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan) or JT-5B (B&L Biotech Ltd.). The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1), J1 (JT-5B / Power-1), K4 (KIS-1D / Power-4), and J4 (JT-5B / Power-4). The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05). The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency.

  7. Self-navigation of a scanning tunneling microscope tip toward a micron-sized graphene sample.

    Science.gov (United States)

    Li, Guohong; Luican, Adina; Andrei, Eva Y

    2011-07-01

    We demonstrate a simple capacitance-based method to quickly and efficiently locate micron-sized conductive samples, such as graphene flakes, on insulating substrates in a scanning tunneling microscope (STM). By using edge recognition, the method is designed to locate and to identify small features when the STM tip is far above the surface, allowing for crash-free search and navigation. The method can be implemented in any STM environment, even at low temperatures and in strong magnetic field, with minimal or no hardware modifications.

  8. Improved design for a low temperature scanning tunneling microscope with an in situ tip treatment stage.

    Science.gov (United States)

    Kim, J-J; Joo, S H; Lee, K S; Yoo, J H; Park, M S; Kwak, J S; Lee, Jinho

    2017-04-01

    The Low Temperature Scanning Tunneling Microscope (LT-STM) is an extremely valuable tool not only in surface science but also in condensed matter physics. For years, numerous new ideas have been adopted to perfect LT-STM performances-Ultra-Low Vibration (ULV) laboratory and the rigid STM head design are among them. Here, we present three improvements for the design of the ULV laboratory and the LT-STM: tip treatment stage, sample cleaving stage, and vibration isolation system. The improved tip treatment stage enables us to perform field emission for the purpose of tip treatment in situ without exchanging samples, while our enhanced sample cleaving stage allows us to cleave samples at low temperature in a vacuum without optical access by a simple pressing motion. Our newly designed vibration isolation system provides efficient space usage while maintaining vibration isolation capability. These improvements enhance the quality of spectroscopic imaging experiments that can last for many days and provide increased data yield, which we expect can be indispensable elements in future LT-STM designs.

  9. [TIPS

    Science.gov (United States)

    Brazzini, Augusto; Carrillo, Alvaro; Cantella, Raúl

    1998-01-01

    Esophageal hemorrage due to variceal bleeding in cirrhotic patients represents a serious problem for the physician in charge, especially in this country where liver transplants are inexistent; and also, it is a drama for the patient and its familly. We propose here the Transjugular Intrahepatic Portosystemic Shunt (TIPS). Twenty one patients were part of a study where 23 TIPS were placed, observing an immediate improval in 18 of them, a rebleeding in 2, within the first 24 and 48 hours. An embolization of the coronary veins was performed in the procedure in 15 patients, and a second intervention due to rebleeding in 2 of them. In the latter patients, the embolization of the coronary veins was rutinary.The survival of the patients has been outstanding.We conclude that this interventional procedure is a worldwide reality in the treatment of esophageal hemorrage by variceal bleeding due to portal hipertension, and it does not cut down the probability of liver transplant, unfortunately inexistent in our country. This procedure results in a low morbimortality with an adequate quality of life.

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

    Science.gov (United States)

    Rashidi, Mohammad; Wolkow, Robert A

    2018-05-23

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

  11. Note: Low-temperature scanning tunneling microscope with detachable scanner and reliable transfer mechanism for tip and sample exchange.

    Science.gov (United States)

    Ge, Weifeng; Wang, Jihao; Wang, Junting; Zhang, Jing; Hou, Yubin; Lu, Qingyou

    2017-12-01

    A homebuilt low-temperature scanning tunneling microscope (STM) featuring a detachable scanner based on a double slider design, along with a reliable transfer mechanism for tip and sample exchange, is present. The coarse motor is decoupled from the scanner, which prevents the motor instabilities including vibrations and drifts from entering the tip-sample loop and thus improves the performance of the STM. In addition, in situ exchange of tips and samples can be implemented easily and reliably using a winch-type transfer mechanism. Atomically resolved images on graphite are demonstrated to show the performance of the proposed STM.

  12. Chiral Majorana fermion modes regulated by a scanning tunneling microscope tip

    Science.gov (United States)

    Zhou, Yan-Feng; Hou, Zhe; Zhang, Ying-Tao; Sun, Qing-Feng

    2018-03-01

    The Majorana fermion can be described by a real wave function with only two phases (zero and π ) which provide a controllable degree of freedom. We propose a strategy to regulate the phase of the chiral Majorana state by coupling with a scanning tunneling microscope tip in a system consisting of a quantum anomalous Hall insulator coupled with a superconductor. With the change in the chemical potential, the chiral Majorana state can be tuned alternately between zero and π , in which the perfect normal tunneling and perfect crossed Andreev reflection appear, respectively. The perfect crossed Andreev reflection, by which a Cooper pair can be split into two electrons going into different terminals completely, leads to a pumping current and distinct quantized resistances. These findings may provide a signature of Majorana fermions and pave a feasible avenue to regulate the phase of the Majorana state.

  13. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    Energy Technology Data Exchange (ETDEWEB)

    Mendrik, Adrienne M; Van Ginneken, Bram; Viergever, Max A [Image Sciences Institute, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Vonken, Evert-jan; De Jong, Hugo W; Riordan, Alan; Van Seeters, Tom; Smit, Ewoud J; Prokop, Mathias, E-mail: a.m.mendrik@gmail.com [Radiology Department, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    2011-07-07

    Cerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of x-ray radiation that can be used per sequential scan is limited, which results in a high level of noise. To detect areas of abnormal perfusion, perfusion parameters are derived from the CTP data, such as the cerebral blood flow (CBF). Algorithms to determine perfusion parameters, especially singular value decomposition, are very sensitive to noise. Therefore, noise reduction is an important preprocessing step for CTP analysis. In this paper, we propose a time-intensity profile similarity (TIPS) bilateral filter to reduce noise in 4D CTP scans, while preserving the time-intensity profiles (fourth dimension) that are essential for determining the perfusion parameters. The proposed TIPS bilateral filter is compared to standard Gaussian filtering, and 4D and 3D (applied separately to each sequential scan) bilateral filtering on both phantom and patient data. Results on the phantom data show that the TIPS bilateral filter is best able to approach the ground truth (noise-free phantom), compared to the other filtering methods (lowest root mean square error). An observer study is performed using CBF maps derived from fifteen CTP scans of acute stroke patients filtered with standard Gaussian, 3D, 4D and TIPS bilateral filtering. These CBF maps were blindly presented to two observers that indicated which map they preferred for (1) gray/white matter differentiation, (2) detectability of infarcted area and (3) overall image quality. Based on these results, the TIPS bilateral filter ranked best and its CBF maps were scored to have the best overall image quality in 100% of the cases by both observers. Furthermore, quantitative CBF and cerebral blood volume values in both the phantom and the

  14. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope.

    Science.gov (United States)

    Fang, Yurui; Zhang, Zhenglong; Sun, Mengtao

    2016-03-01

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10(-7) Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  15. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yurui [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); Bionanophotonics, Department of Applied Physics, Chalmers University of Technology, Göteborg, SE 41296 (Sweden); Zhang, Zhenglong [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); School of Physics and Information Technology, Shaanxi Normal University, 710062 Xi’an (China); Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Sun, Mengtao, E-mail: mtsun@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China)

    2016-03-15

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10{sup −7} Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  16. Silver nanowires for highly reproducible cantilever based AFM-TERS microscopy: towards a universal TERS probe.

    Science.gov (United States)

    Walke, Peter; Fujita, Yasuhiko; Peeters, Wannes; Toyouchi, Shuichi; Frederickx, Wout; De Feyter, Steven; Uji-I, Hiroshi

    2018-04-26

    Tip-enhanced Raman scattering (TERS) microscopy is a unique analytical tool to provide complementary chemical and topographic information of surfaces with nanometric resolution. However, difficulties in reliably producing the necessary metallized scanning probe tips has limited its widespread utilisation, particularly in the case of cantilever-based atomic force microscopy. Attempts to alleviate tip related issues using colloidal or bottom-up engineered tips have so far not reported consistent probes for both Raman and topographic imaging. Here we demonstrate the reproducible fabrication of cantilever-based high-performance TERS probes for both topographic and Raman measurements, based on an approach that utilises noble metal nanowires as the active TERS probe. The tips show 10 times higher TERS contrasts than the most typically used electrochemically-etched tips, and show a reproducibility for TERS greater than 90%, far greater than found with standard methods. We show that TERS can be performed in tapping as well as contact AFM mode, with optical resolutions around or below 15 nm, and with a maximum resolution achieved in tapping-mode of 6 nm. Our work illustrates that superior TERS probes can be produced in a fast and cost-effective manner using simple wet-chemistry methods, leading to reliable and reproducible high-resolution and high-sensitivity TERS, and thus renders the technique applicable for a broad community.

  17. A more comprehensive modeling of atomic force microscope cantilever

    International Nuclear Information System (INIS)

    Mahdavi, M.H.; Farshidianfar, A.; Tahani, M.; Mahdavi, S.; Dalir, H.

    2008-01-01

    This paper focuses on the development of a complete model of an atomic force microscope (AFM) micro-cantilever beam, based on considering the effects of four major factors in modeling the cantilever. They are: rotary inertia and shear deformation of the beam and mass and rotary inertia of the tip. A method based on distributed-parameter modeling approach is proposed to solve the governing equations. The comparisons generally show a very good agreement between the present results and the results of other investigators. As expected, rotary inertia and shear deformation of the beam decrease resonance frequency especially at high ratio of cantilever thickness to its length, and it is relatively more pronounced for higher-order frequencies, than lower ones. Mass and rotary inertia of the tip have similar effects when the mass-ratio of the tip to the cantilever is high. Moreover, the influence of each of these four factors, thickness of the cantilever, density of the tip and inclination of the cantilever on the resonance frequencies has been investigated, separately. It is felt that this work might help the engineers in reducing AFM micro-cantilever design time, by providing insight into the effects of various parameters with the micro-cantilever.

  18. Electrical conduction of organic ultrathin films evaluated by an independently driven double-tip scanning tunneling microscope.

    Science.gov (United States)

    Takami, K; Tsuruta, S; Miyake, Y; Akai-Kasaya, M; Saito, A; Aono, M; Kuwahara, Y

    2011-11-02

    The electrical transport properties of organic thin films within the micrometer scale have been evaluated by a laboratory-built independently driven double-tip scanning tunneling microscope, operating under ambient conditions. The two tips were used as point contact electrodes, and current in the range from 0.1 pA to 100 nA flowing between the two tips through the material can be detected. We demonstrated two-dimensional contour mapping of the electrical resistance on a poly(3-octylthiophene) thin films as shown below. The obtained contour map clearly provided an image of two-dimensional electrical conductance between two point electrodes on the poly(3-octylthiophene) thin film. The conductivity of the thin film was estimated to be (1-8) × 10(-6) S cm(-1). Future prospects and the desired development of multiprobe STMs are also discussed.

  19. Tip-enhanced near-field Raman spectroscopy with a scanning tunneling microscope and side-illumination optics.

    Science.gov (United States)

    Yi, K J; He, X N; Zhou, Y S; Xiong, W; Lu, Y F

    2008-07-01

    Conventional Raman spectroscopy (RS) suffers from low spatial resolution and low detection sensitivity due to the optical diffraction limit and small interaction cross sections. It has been reported that a highly localized and significantly enhanced electromagnetic field could be generated in the proximity of a metallic tip illuminated by a laser beam. In this study, a tip-enhanced RS system was developed to both improve the resolution and enhance the detection sensitivity using the tip-enhanced near-field effects. This instrument, by combining RS with a scanning tunneling microscope and side-illumination optics, demonstrated significant enhancement on both optical sensitivity and spatial resolution using either silver (Ag)-coated tungsten (W) tips or gold (Au) tips. The sensitivity improvement was verified by observing the enhancement effects on silicon (Si) substrates. Lateral resolution was verified to be below 100 nm by mapping Ag nanostructures. By deploying the depolarization technique, an apparent enhancement of 175% on Si substrates was achieved. Furthermore, the developed instrument features fast and reliable optical alignment, versatile sample adaptability, and effective suppression of far-field signals.

  20. Electroluminescence of a polythiophene molecular wire suspended between a metallic surface and the tip of a scanning tunneling microscope.

    Science.gov (United States)

    Reecht, Gaël; Scheurer, Fabrice; Speisser, Virginie; Dappe, Yannick J; Mathevet, Fabrice; Schull, Guillaume

    2014-01-31

    The electroluminescence of a polythiophene wire suspended between a metallic surface and the tip of a scanning tunneling microscope is reported. Under positive sample voltage, the spectral and voltage dependencies of the emitted light are consistent with the fluorescence of the wire junction mediated by localized plasmons. This emission is strongly attenuated for the opposite polarity. Both emission mechanism and polarity dependence are similar to what occurs in organic light emitting diodes (OLED) but at the level of a single molecular wire.

  1. High-speed dynamic atomic force microscopy by using a Q-controlled cantilever eigenmode as an actuator

    Energy Technology Data Exchange (ETDEWEB)

    Balantekin, M., E-mail: mujdatbalantekin@iyte.edu.tr

    2015-02-15

    We present a high-speed operating method with feedback to be used in dynamic atomic force microscope (AFM) systems. In this method we do not use an actuator that has to be employed to move the tip or the sample as in conventional AFM setups. Instead, we utilize a Q-controlled eigenmode of an AFM cantilever to perform the function of the actuator. Simulations show that even with an ordinary tapping-mode cantilever, imaging speed can be increased by about 2 orders of magnitude compared to conventional dynamic AFM imaging. - Highlights: • A high-speed imaging method is developed for dynamic-AFM systems. • An eigenmode of an AFM cantilever is utilized to perform fast actuation. • Simulations show 2 orders of magnitude increase in scan speed. • The time spent for dynamic-AFM imaging experiments will be minimized.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2005-07-01

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

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

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  4. Scanning tunneling microscopy measurements of the spin Hall effect in tungsten films by using iron-coated tungsten tips

    Directory of Open Access Journals (Sweden)

    Ting Xie

    2018-05-01

    Full Text Available Scanning tunneling microscopy experiments using iron-coated tungsten tips and current-carrying tungsten films have been conducted. An asymmetry of the tunneling current with respect to the change of the direction of the bias current through a tungsten film has been observed. It is argued that this asymmetry is a manifestation of the spin Hall effect in the current-carrying tungsten film. Nanoscale variations of this asymmetry across the tungsten film have been studied by using the scanning tunneling microscopy technique.

  5. Scanning tunneling microscopy measurements of the spin Hall effect in tungsten films by using iron-coated tungsten tips

    Science.gov (United States)

    Xie, Ting; Dreyer, Michael; Bowen, David; Hinkel, Dan; Butera, R. E.; Krafft, Charles; Mayergoyz, Isaak

    2018-05-01

    Scanning tunneling microscopy experiments using iron-coated tungsten tips and current-carrying tungsten films have been conducted. An asymmetry of the tunneling current with respect to the change of the direction of the bias current through a tungsten film has been observed. It is argued that this asymmetry is a manifestation of the spin Hall effect in the current-carrying tungsten film. Nanoscale variations of this asymmetry across the tungsten film have been studied by using the scanning tunneling microscopy technique.

  6. Electrostatic force microscopy with a self-sensing piezoresistive cantilever

    International Nuclear Information System (INIS)

    Pi, U. H.; Kye, J. I.; Shin, S.; Khim, Z. G.; Hong, J. W.; Yoon, S.

    2003-01-01

    We present a new method for electrostatic force microscopy (EFM) using a piezoresistive cantilever instead of the conventional cantilever with an optical detector. In EFM with a piezoresistive cantilever, the electrostatic force between the tip and the sample is monitored by sensing the change in the resistance of the piezoresistive cantilever at a frequency of several tens of kHz. A large stray capacitance effect can be rejected by using an appropriate phase tuning of the phase-sensitive detection. We observed the ferroelectric domain images of a triglycine sulfate single crystal. We could also write fine patterns on a lead-zirconate-titanate (PZT) thin film through domain reversal by applying various dc voltages between the tip and the sample. We suggest that the EFM technique using a self-sensing and self-actuating piezoresistive cantilever can be applied to a high-density data storage field

  7. Dual-tip magnetic force microscopy with suppressed influence on magnetically soft samples

    International Nuclear Information System (INIS)

    Precner, Marián; Fedor, Ján; Šoltýs, Ján; Cambel, Vladimír

    2015-01-01

    Standard magnetic force microscopy (MFM) is considered as a powerful tool used for magnetic field imaging at nanoscale. The method consists of two passes realized by the magnetic tip. Within the first one, the topography pass, the magnetic tip directly touches the magnetic sample. Such contact perturbs the magnetization of the sample explored. To avoid the sample touching the magnetic tip, we present a new approach to magnetic field scanning by segregating the topological and magnetic scans with two different tips located on a cut cantilever. The approach minimizes the disturbance of sample magnetization, which could be a major problem in conventional MFM images of soft magnetic samples. By cutting the cantilever in half using the focused ion beam technique, we create one sensor with two different tips—one tip is magnetized, and the other one is left non-magnetized. The non-magnetized tip is used for topography and the magnetized one for the magnetic field imaging. The method developed we call dual-tip magnetic force microscopy (DT-MFM). We describe in detail the dual-tip fabrication process. In the experiments, we show that the DT-MFM method reduces significantly the perturbations of the magnetic tip as compared to the standard MFM method. The present technique can be used to investigate microscopic magnetic domain structures in a variety of magnetic samples and is relevant in a wide range of applications, e.g., data storage and biomedicine. (paper)

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

    KAUST Repository

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

    2012-01-01

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

  9. Calibration of atomic force microscope cantilevers using standard and inverted static methods assisted by FIB-milled spatial markers

    International Nuclear Information System (INIS)

    Slattery, Ashley D; Blanch, Adam J; Quinton, Jamie S; Gibson, Christopher T

    2013-01-01

    Static methods to determine the spring constant of AFM cantilevers have been widely used in the scientific community since the importance of such calibration techniques was established nearly 20 years ago. The most commonly used static techniques involve loading a trial cantilever with a known force by pressing it against a pre-calibrated standard or reference cantilever. These reference cantilever methods have a number of sources of uncertainty, which include the uncertainty in the measured spring constant of the standard cantilever, the exact position of the loading point on the reference cantilever and how closely the spring constant of the trial and reference cantilever match. We present a technique that enables users to minimize these uncertainties by creating spatial markers on reference cantilevers using a focused ion beam (FIB). We demonstrate that by combining FIB spatial markers with an inverted reference cantilever method, AFM cantilevers can be accurately calibrated without the tip of the test cantilever contacting a surface. This work also demonstrates that for V-shaped cantilevers it is possible to determine the precise loading position by AFM imaging the section of the cantilever where the two arms join. Removing tip-to-surface contact in both the reference cantilever method and sensitivity calibration is a significant improvement, since this is an important consideration for AFM users that require the imaging tip to remain in pristine condition before commencing measurements. Uncertainties of between 5 and 10% are routinely achievable with these methods. (paper)

  10. Modular design of AFM probe with sputtered silicon tip

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Thaysen, Jacob; Bouwstra, Siebe

    2001-01-01

    of the thin films constituting the cantilever. The AFM probe has an integrated tip made of a thick sputtered silicon layer, which is deposited after the probe has been defined and just before the cantilevers are released. The tips are so-called rocket tips made by reactive ion etching. We present probes...

  11. Chain polymerization of diacetylene compound multilayer films on the topmost surface initiated by a scanning tunneling microscope tip.

    Science.gov (United States)

    Takajo, Daisuke; Okawa, Yuji; Hasegawa, Tsuyoshi; Aono, Masakazu

    2007-05-08

    Chain polymerizations of diacetylene compound multilayer films on graphite substrates were examined with a scanning tunneling microscope (STM) at the liquid/solid interface of the phenyloctane solution. The first layer grew very quickly into many small domains. This was followed by the slow formation of the piled up layers into much larger domains. Chain polymerization on the topmost surface layer could be initiated by applying a pulsed voltage between the STM tip and the substrate, usually producing a long polymer of submicrometer length. In contrast, polymerizations on the underlying layer were never observed. This can be explained by a conformation model in which the polymer backbone is lifted up.

  12. Controlling molecular condensation/diffusion of copper phthalocyanine by local electric field induced with scanning tunneling microscope tip

    Science.gov (United States)

    Nagaoka, Katsumi; Yaginuma, Shin; Nakayama, Tomonobu

    2018-02-01

    We have discovered the condensation/diffusion phenomena of copper phthalocyanine (CuPc) molecules controlled with a pulsed electric field induced by the scanning tunneling microscope tip. This behavior is not explained by the conventional induced dipole model. In order to understand the mechanism, we have measured the electronic structure of the molecule by tunneling spectroscopy and also performed theoretical calculations on molecular orbitals. These data clearly indicate that the molecule is positively charged owing to charge transfer to the substrate, and that hydrogen bonding exists between CuPc molecules, which makes the molecular island stable.

  13. Three-way flexible cantilever probes for static contact

    International Nuclear Information System (INIS)

    Wang, Fei; Petersen, Dirch H; Hansen, Christian; Mortensen, Dennis; Friis, Lars; Hansen, Ole; Jensen, Helle V

    2011-01-01

    In micro four-point probe measurements, three-way flexible L-shaped cantilever probes show significant advantages over conventional straight cantilever probes. The L-shaped cantilever allows static contact to the sample surface which reduces the frictional wear of the cantilever tips. We analyze the geometrical design space that must be fulfilled for the cantilevers to obtain static contact with the test sample. The design space relates the spring constant tensor of the cantilevers to the minimal value of the static tip-to-sample friction coefficient. Using an approximate model, we provide the analytical calculation of the compliance matrix of the L-shaped cantilever. Compared to results derived from finite element model simulations, the theoretical model provides a good qualitative analysis while deviations for the absolute values are seen. From a statistical analysis, the deviation is small for cantilevers with low effective spring constants, while the deviation is significant for large spring constants where the quasi one-dimensional approximation is no longer valid

  14. Resonance frequencies of AFM cantilevers in contact with a surface

    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); Rost, M.J., E-mail: Rost@physics.leidenuniv.nl [Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden (Netherlands)

    2016-12-15

    To make the forces in an Atomic Force Microscope that operates in a dynamic mode with one or multiple vibrations applied to the cantilever, quantitative, one needs to relate a change in resonance frequency of the cantilever to a specific tip–sample interaction. Due to the time dependence of the force between the tip and sample caused by the vibrations, this task is not only difficult, but in fact only possible to solve for certain limiting cases, if one follows common theoretical approaches with a Taylor expansion around the deflection point. Here, we present an analytical method for calculating the resonance frequencies of the cantilever that is valid for any tip–sample interaction. Instead of linearizing the tip–sample interaction locally, we calculate an averaged, weighted linearization taking into account all positions of the tip while vibrating. Our method bridges, therefore, the difficult gap between a free oscillating cantilever and a cantilever that is pushed infinitely hard into contact with a surface, which describes a clamped-pinned boundary condition. For a correct description of the cantilever dynamics, we take into account both the tip mass and the tip moment of inertia. Applying our model, we show that it is possible to calculate the modal response of a cantilever as a function of the tip–sample interaction strength. Based on these modal vibration characteristics, we show that the higher resonance frequencies of a cantilever are completely insensitive to the strength of the tip–sample interaction. - Highlights: • A method to calculate the resonances of AFM cantilevers under any force is proposed. • The analytical model is based on Euler-beam theory. • The shift in resonance frequency due to forces decrease with increasing mode number. • The proposed method enables quantitative ultrasound AFM experiments. • Our results explain also the applicability of the higher modes in SubSurface-AFM.

  15. Modified cantilevers to probe unambiguously out-of-plane piezoresponse

    Science.gov (United States)

    Alyabyeva, Natalia; Ouvrard, Aimeric; Lindfors-Vrejoiu, Ionela; Kolomiytsev, Alexey; Solodovnik, Maxim; Ageev, Oleg; McGrouther, Damien

    2018-06-01

    We demonstrate and investigate the coupling of contributions from both in-plane (IP) polarization and out-of-plane (OP) components in BiFeO3 (BFO) thin-film polarization probed by piezoresponse force microscopy (PFM). Such coupling leads to image artifacts which prevent the correct determination of OP polarization vector directions and the corresponding piezoelectric coefficient d33. Using material strength theory with a one-dimensional modeling of the cantilever oscillation amplitude under electrostatic and elastic forces as a function of the tip length, we have evidenced the impact of IP piezoresponse to the OP signal for tip length longer than 4 μm. The IP polarization vector induces a significant longitudinal bending of the cantilever, due to the small spring constant of long tips, which provokes a normal deviation superimposed to the OP piezoresponse. These artifacts can be reduced by increasing the longitudinal spring constant of the cantilever by shortening the tip length. Standard cantilevers with 15-μm-long tips were modified to reach the desired tip length, using focused ion-beam techniques and tested using PFM on the same BFO thin film. Tip length shortening has strongly reduced IP artifacts as expected, while the impact of nonlocal electrostatic forces, becoming predominant for tips shorter than 1 μm, has led to a non-negligible deflection offset. For shorter tips, a strong electric field from a cantilever beam can induce polarization switching as observed for a 0.5-μm-long tip. Tip length ranging from 1 to 4 μm allowed minimizing both artifacts to probe unambiguously OP piezoresponse and quantify the d33 piezoelectric coefficient.

  16. Customized atomic force microscopy probe by focused-ion-beam-assisted tip transfer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Andrew; Butte, Manish J., E-mail: manish.butte@stanford.edu [Department of Pediatrics, Division of Immunology, Allergy and Rheumatology, Stanford University, Stanford, California 94305 (United States)

    2014-08-04

    We present a technique for transferring separately fabricated tips onto tipless atomic force microscopy (AFM) cantilevers, performed using focused ion beam-assisted nanomanipulation. This method addresses the need in scanning probe microscopy for certain tip geometries that cannot be achieved by conventional lithography. For example, in probing complex layered materials or tall biological cells using AFM, a tall tip with a high-aspect-ratio is required to avoid artifacts caused by collisions of the tip's sides with the material being probed. We show experimentally that tall (18 μm) cantilever tips fabricated by this approach reduce squeeze-film damping, which fits predictions from hydrodynamic theory, and results in an increased quality factor (Q) of the fundamental flexural mode. We demonstrate that a customized tip's well-defined geometry, tall tip height, and aspect ratio enable improved measurement of elastic moduli by allowing access to low-laying portions of tall cells (T lymphocytes). This technique can be generally used to attach tips to any micromechanical device when conventional lithography of tips cannot be accomplished.

  17. Accurate spring constant calibration for very stiff atomic force microscopy cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Grutzik, Scott J.; Zehnder, Alan T. [Field of Theoretical and Applied Mechanics, Cornell University, Ithaca, New York 14853 (United States); Gates, Richard S.; Gerbig, Yvonne B.; Smith, Douglas T.; Cook, Robert F. [Nanomechanical Properties Group, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

    2013-11-15

    There are many atomic force microscopy (AFM) applications that rely on quantifying the force between the AFM cantilever tip and the sample. The AFM does not explicitly measure force, however, so in such cases knowledge of the cantilever stiffness is required. In most cases, the forces of interest are very small, thus compliant cantilevers are used. A number of methods have been developed that are well suited to measuring low stiffness values. However, in some cases a cantilever with much greater stiffness is required. Thus, a direct, traceable method for calibrating very stiff (approximately 200 N/m) cantilevers is presented here. The method uses an instrumented and calibrated nanoindenter to determine the stiffness of a reference cantilever. This reference cantilever is then used to measure the stiffness of a number of AFM test cantilevers. This method is shown to have much smaller uncertainty than previously proposed methods. An example application to fracture testing of nanoscale silicon beam specimens is included.

  18. Accurate spring constant calibration for very stiff atomic force microscopy cantilevers

    International Nuclear Information System (INIS)

    Grutzik, Scott J.; Zehnder, Alan T.; Gates, Richard S.; Gerbig, Yvonne B.; Smith, Douglas T.; Cook, Robert F.

    2013-01-01

    There are many atomic force microscopy (AFM) applications that rely on quantifying the force between the AFM cantilever tip and the sample. The AFM does not explicitly measure force, however, so in such cases knowledge of the cantilever stiffness is required. In most cases, the forces of interest are very small, thus compliant cantilevers are used. A number of methods have been developed that are well suited to measuring low stiffness values. However, in some cases a cantilever with much greater stiffness is required. Thus, a direct, traceable method for calibrating very stiff (approximately 200 N/m) cantilevers is presented here. The method uses an instrumented and calibrated nanoindenter to determine the stiffness of a reference cantilever. This reference cantilever is then used to measure the stiffness of a number of AFM test cantilevers. This method is shown to have much smaller uncertainty than previously proposed methods. An example application to fracture testing of nanoscale silicon beam specimens is included

  19. Correction of the tip convolution effects in the imaging of nanostructures studied through scanning force microscopy

    International Nuclear Information System (INIS)

    Canet-Ferrer, Josep; Coronado, Eugenio; Forment-Aliaga, Alicia; Pinilla-Cienfuegos, Elena

    2014-01-01

    AFM images are always affected by artifacts arising from tip convolution effects, resulting in a decrease in the lateral resolution of this technique. The magnitude of such effects is described by means of geometrical considerations, thereby providing better understanding of the convolution phenomenon. We demonstrate that for a constant tip radius, the convolution error is increased with the object height, mainly for the narrowest motifs. Certain influence of the object shape is observed between rectangular and elliptical objects with the same height. Such moderate differences are essentially expected among elongated objects; in contrast they are reduced as the object aspect ratio is increased. Finally, we propose an algorithm to study the influence of the size, shape and aspect ratio of different nanometric motifs on a flat substrate. Indeed, with this algorithm, convolution artifacts can be extended to any kind of motif including real surface roughness. From the simulation results we demonstrate that in most cases the real motif’s width can be estimated from AFM images without knowing its shape in detail. (paper)

  20. In-situ piezoresponse force microscopy cantilever mode shape profiling

    International Nuclear Information System (INIS)

    Proksch, R.

    2015-01-01

    The frequency-dependent amplitude and phase in piezoresponse force microscopy (PFM) measurements are shown to be a consequence of the Euler-Bernoulli (EB) dynamics of atomic force microscope (AFM) cantilever beams used to make the measurements. Changes in the cantilever mode shape as a function of changes in the boundary conditions determine the sensitivity of cantilevers to forces between the tip and the sample. Conventional PFM and AFM measurements are made with the motion of the cantilever measured at one optical beam detector (OBD) spot location. A single OBD spot location provides a limited picture of the total cantilever motion, and in fact, experimentally observed cantilever amplitude and phase are shown to be strongly dependent on the OBD spot position for many measurements. In this work, the commonly observed frequency dependence of PFM response is explained through experimental measurements and analytic theoretical EB modeling of the PFM response as a function of both frequency and OBD spot location on a periodically poled lithium niobate sample. One notable conclusion is that a common choice of OBD spot location—at or near the tip of the cantilever—is particularly vulnerable to frequency dependent amplitude and phase variations stemming from dynamics of the cantilever sensor rather than from the piezoresponse of the sample

  1. Improving tapping mode atomic force microscopy with piezoelectric cantilevers

    International Nuclear Information System (INIS)

    Rogers, B.; Manning, L.; Sulchek, T.; Adams, J.D.

    2004-01-01

    This article summarizes improvements to the speed, simplicity and versatility of tapping mode atomic force microscopy (AFM). Improvements are enabled by a piezoelectric microcantilever with a sharp silicon tip and a thin, low-stress zinc oxide (ZnO) film to both actuate and sense deflection. First, we demonstrate self-sensing tapping mode without laser detection. Similar previous work has been limited by unoptimized probe tips, cantilever thicknesses, and stress in the piezoelectric films. Tests indicate self-sensing amplitude resolution is as good or better than optical detection, with double the sensitivity, using the same type of cantilever. Second, we demonstrate self-oscillating tapping mode AFM. The cantilever's integrated piezoelectric film serves as the frequency-determining component of an oscillator circuit. The circuit oscillates the cantilever near its resonant frequency by applying positive feedback to the film. We present images and force-distance curves using both self-sensing and self-oscillating techniques. Finally, high-speed tapping mode imaging in liquid, where electric components of the cantilever require insulation, is demonstrated. Three cantilever coating schemes are tested. The insulated microactuator is used to simultaneously vibrate and actuate the cantilever over topographical features. Preliminary images in water and saline are presented, including one taken at 75.5 μm/s - a threefold improvement in bandwidth versus conventional piezotube actuators

  2. Characterization of piesoelectric ZnO thin films and the fabrication of piezoelectric micro-cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Raegan Lynn [Iowa State Univ., Ames, IA (United States)

    2005-01-01

    In Atomic Force Microscopy (AFM), a microcantilever is raster scanned across the surface of a sample in order to obtain a topographical image of the sample's surface. In a traditional, optical AFM, the sample rests on a bulk piezoelectric tube and a control loop is used to control the tip-sample separation by actuating the piezo-tube. This method has several disadvantages--the most noticeable one being that response time of the piezo-tube is rather long which leads to slow imaging speeds. One possible solution aimed at improving the speed of imaging is to incorporate a thin piezoelectric film on top of the cantilever beam. This design not only improves the speed of imaging because the piezoelectric film replaces the piezo-tube as an actuator, but the film can also act as a sensor. In addition, the piezoelectric film can excite the cantilever beam near its resonance frequency. This project aims to fabricate piezoelectric microcantilevers for use in the AFM. Prior to fabricating the cantilevers and also part of this project, a systematic study was performed to examine the effects of deposition conditions on the quality of piezoelectric ZnO thin films deposited by RF sputtering. These results will be presented. The deposition parameters that produced the highest quality ZnO film were used in the fabrication of the piezoelectric cantilevers. Unfortunately, the fabricated cantilevers warped due to the intrinsic stress of the ZnO film and were therefore not usable in the AFM. The complete fabrication process will be detailed, the results will be discussed and reasons for the warping will be examined.

  3. Near-Field Imaging of Free Carriers in ZnO Nanowires with a Scanning Probe Tip Made of Heavily Doped Germanium

    Science.gov (United States)

    Sakat, Emilie; Giliberti, Valeria; Bollani, Monica; Notargiacomo, Andrea; Pea, Marialilia; Finazzi, Marco; Pellegrini, Giovanni; Hugonin, Jean-Paul; Weber-Bargioni, Alexander; Melli, Mauro; Sassolini, Simone; Cabrini, Stefano; Biagioni, Paolo; Ortolani, Michele; Baldassarre, Leonetta

    2017-11-01

    A novel scanning probe tip made of heavily doped semiconductor is fabricated and used instead of standard gold-coated tips in infrared scattering-type near-field microscopy. Midinfrared near-field microscopy experiments are conducted on ZnO nanowires with a lateral resolution better than 100 nm, using tips made of heavily electron-doped germanium with a plasma frequency in the midinfrared (plasma wavelength of 9.5 μ m ). Nanowires embedded in a dielectric matrix are imaged at two wavelengths, 11.3 and 8.0 μ m , above and below the plasma wavelength of the tips. An opposite sign of the imaging contrasts between the nanowire and the dielectric matrix is observed at the two infrared wavelengths, indicating a clear role of the free-electron plasma in the heavily doped germanium tip in building the imaging contrast. Electromagnetic simulations with a multispherical dipole model accounting for the finite size of the tip are well consistent with the experiments. By comparison of the simulated and measured imaging contrasts, an estimate for the local free-carrier density in the investigated ZnO nanowires in the low 1019 cm-3 range is retrieved. The results are benchmarked against the scattering intensity and phase maps obtained on the same sample with a gold-coated probe tip in pseudoheterodyne detection mode.

  4. Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

    Directory of Open Access Journals (Sweden)

    Walla Frederik

    2018-01-01

    Full Text Available We investigated the excitation of surface plasmon polaritons on gold films with the metallized probe tip of a scattering-type scanning near-field optical microscope (s-SNOM. The emission of the polaritons from the tip, illuminated by near-infrared laser radiation, was found to be anisotropic and not circularly symmetric as expected on the basis of literature data. We furthermore identified an additional excitation channel via light that was reflected off the tip and excited the plasmon polaritons at the edge of the metal film. Our results, while obtained for a non-rotationally-symmetric type of probe tip and thus specific for this situation, indicate that when an s-SNOM is employed for the investigation of plasmonic structures, the unintentional excitation of surface waves and anisotropic surface wave propagation must be considered in order to correctly interpret the signatures of plasmon polariton generation and propagation.

  5. Two-dimensional dopant profiling by electrostatic force microscopy using carbon nanotube modified cantilevers

    International Nuclear Information System (INIS)

    Chin, S.-C.; Chang, Y.-C.; Chang, C.-S.; Tsong, T T; Hsu, Chen-Chih; Wu, Chih-I; Lin, W-H; Woon, W-Y; Lin, L-T; Tao, H-J

    2008-01-01

    A two-dimensional (2D) dopant profiling technique is demonstrated in this work. We apply a unique cantilever probe in electrostatic force microscopy (EFM) modified by the attachment of a multiwalled carbon nanotube (MWNT). Furthermore, the tip apex of the MWNT was trimmed to the sharpness of a single-walled carbon nanotube (SWNT). This ultra-sharp MWNT tip helps us to resolve dopant features to within 10 nm in air, which approaches the resolution achieved by ultra-high vacuum scanning tunnelling microscopy (UHV STM). In this study, the CNT-probed EFM is used to profile 2D buried dopant distribution under a nano-scale device structure and shows the feasibility of device characterization for sub-45 nm complementary metal-oxide-semiconductor (CMOS) field-effect transistors

  6. Calibration of higher eigenmodes of cantilevers

    International Nuclear Information System (INIS)

    Labuda, Aleksander; Kocun, Marta; Walsh, Tim; Meinhold, Jieh; Proksch, Tania; Meinhold, Waiman; Anderson, Caleb; Proksch, Roger; Lysy, Martin

    2016-01-01

    A method is presented for calibrating the higher eigenmodes (resonant modes) of atomic force microscopy cantilevers that can be performed prior to any tip-sample interaction. The method leverages recent efforts in accurately calibrating the first eigenmode by providing the higher-mode stiffness as a ratio to the first mode stiffness. A one-time calibration routine must be performed for every cantilever type to determine a power-law relationship between stiffness and frequency, which is then stored for future use on similar cantilevers. Then, future calibrations only require a measurement of the ratio of resonant frequencies and the stiffness of the first mode. This method is verified through stiffness measurements using three independent approaches: interferometric measurement, AC approach-curve calibration, and finite element analysis simulation. Power-law values for calibrating higher-mode stiffnesses are reported for several cantilever models. Once the higher-mode stiffnesses are known, the amplitude of each mode can also be calibrated from the thermal spectrum by application of the equipartition theorem.

  7. Calibration of higher eigenmodes of cantilevers

    Energy Technology Data Exchange (ETDEWEB)

    Labuda, Aleksander; Kocun, Marta; Walsh, Tim; Meinhold, Jieh; Proksch, Tania; Meinhold, Waiman; Anderson, Caleb; Proksch, Roger [Asylum Research, an Oxford Instruments Company, Santa Barbara, California 93117 (United States); Lysy, Martin [Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2016-07-15

    A method is presented for calibrating the higher eigenmodes (resonant modes) of atomic force microscopy cantilevers that can be performed prior to any tip-sample interaction. The method leverages recent efforts in accurately calibrating the first eigenmode by providing the higher-mode stiffness as a ratio to the first mode stiffness. A one-time calibration routine must be performed for every cantilever type to determine a power-law relationship between stiffness and frequency, which is then stored for future use on similar cantilevers. Then, future calibrations only require a measurement of the ratio of resonant frequencies and the stiffness of the first mode. This method is verified through stiffness measurements using three independent approaches: interferometric measurement, AC approach-curve calibration, and finite element analysis simulation. Power-law values for calibrating higher-mode stiffnesses are reported for several cantilever models. Once the higher-mode stiffnesses are known, the amplitude of each mode can also be calibrated from the thermal spectrum by application of the equipartition theorem.

  8. Construction of a four tip scanning tunneling microscope/scanning electron microscope combination and conductivity measurements of silicide nanowires; Aufbau einer Vierspitzen-Rastertunnelmikroskop/Rasterelektronenmikroskop-Kombination und Leitfaehigkeitsmessungen an Silizid Nanodraehten

    Energy Technology Data Exchange (ETDEWEB)

    Zubkov, Evgeniy

    2013-09-01

    In this work the combination of a four-tip scanning tunneling microscope with a scanning electron microscope is presented. By means of this apparatus it is possible to perform the conductivity measurements on the in-situ prepared nanostructures in ultra-high vacuum. With the aid of a scanning electron microscope (SEM), it becomes possible to position the tunneling tips of the four-tip scanning tunneling microscope (STM), so that an arrangement for a four-point probe measurement on nanostructures can be obtained. The STM head was built according to the novel coaxial Beetle concept. This concept allows on the one hand, a very compact arrangement of the components of the STM and on the other hand, the new-built STM head has a good mechanical stability, in order to achieve atomic resolution with all four STM units. The atomic resolution of the STM units was confirmed by scanning a Si(111)-7 x 7 surface. The thermal drift during the STM operation, as well as the resonant frequencies of the mechanical structure of the STM head, were determined. The scanning electron microscope allows the precise and safe navigation of the tunneling tips on the sample surface. Multi tip spectroscopy with up to four STM units can be performed synchronously. To demonstrate the capabilities of the new-built apparatus the conductivity measurements were carried out on metallic yttrium silicide nanowires. The nanowires were prepared by the in-situ deposition of yttrium on a heated Si(110) sample surface. Current-voltage curves were recorded on the nanowires and on the wetting layer in-between. The curves indicate an existence of the Schottky barrier between the yttrium silicide nanowires and the silicon bulk. By means of the two-tip measurements with a gate, the insulating property of the Schottky barrier has been confirmed. Using this Schottky barrier, it is possible to limit the current to the nanowire and to prevent it from flowing through the silicon bulk. A four-tip resistance measurement

  9. Conductive oxide cantilever for cryogenic nano-potentiometry

    International Nuclear Information System (INIS)

    Hiroya, Tsutomu; Inagaki, Katsuhiko; Tanda, Satoshi; Tsuneta, Taku; Yamaya, Kazuhiko

    2003-01-01

    Nanoscale electrical transport properties have attracted attentions because of new phenomena such as ballistic transport, quantized resistance, and Coulomb blockade. For measurement of nanoscale resistance, we have been developing a cryogenic atomic force microscope that can operate at 1.8 K. To use it as an electrode, we coated the cantilever with conductive oxides of TiO and indium tin oxide (ITO). We verified that TiO and ITO thin films remain conductive even at 4.2 K. Also we measured I-V characteristics of the tip-sample contact with a standard sample of NbSe 2 single crystal, and found that the conductive coats were not lost under large stresses due to the tip-sample contact. Moreover, we succeeded in obtaining a room temperature nano-potentiometry of a gold thin film with the ITO coated cantilever. In conclusion, the TiO and ITO coated cantilevers are applicable to cryogenic nano-potentiometry

  10. Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

    International Nuclear Information System (INIS)

    Xu, J.; Tang, J.

    2015-01-01

    This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined

  11. Multi-directional energy harvesting by piezoelectric cantilever-pendulum with internal resonance

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Tang, J., E-mail: jtang@engr.uconn.edu [Department of Mechanical Engineering, The University of Connecticut, Storrs, Connecticut 06269 (United States)

    2015-11-23

    This letter reports a piezoelectric cantilever-pendulum design for multi-directional energy harvesting. A pendulum is attached to the tip of a piezoelectric cantilever-type energy harvester. This design aims at taking advantage of the nonlinear coupling between the pendulum motion in 3-dimensional space and the beam bending vibration at resonances. Experimental studies indicate that, under properly chosen parameters, 1:2 internal resonance can be induced, which enables the multi-directional energy harvesting with a single cantilever. The advantages of the design with respect to traditional piezoelectric cantilever are examined.

  12. Note: A resonating reflector-based optical system for motion measurement in micro-cantilever arrays

    International Nuclear Information System (INIS)

    Sathishkumar, P.; Punyabrahma, P.; Sri Muthu Mrinalini, R.; Jayanth, G. R.

    2015-01-01

    A robust, compact optical measurement unit for motion measurement in micro-cantilever arrays enables development of portable micro-cantilever sensors. This paper reports on an optical beam deflection-based system to measure the deflection of micro-cantilevers in an array that employs a single laser source, a single detector, and a resonating reflector to scan the measurement laser across the array. A strategy is also proposed to extract the deflection of individual cantilevers from the acquired data. The proposed system and measurement strategy are experimentally evaluated and demonstrated to measure motion of multiple cantilevers in an array

  13. Reconstruction of the Tip-Surface Interaction Potential by Analysis of the Brownian Motion of an Atomic Force Microscope Tip

    NARCIS (Netherlands)

    Willemsen, O.H.; Kuipers, L.; van der Werf, Kees; de Grooth, B.G.; Greve, Jan

    2000-01-01

    The thermal movement of an atomic force microscope (AFM) tip is used to reconstruct the tip-surface interaction potential. If a tip is brought into the vicinity of a surface, its movement is governed by the sum of the harmonic cantilever potential and the tip-surface interaction potential. By

  14. Scanning electrochemical microscopy. 47. Imaging electrocatalytic activity for oxygen reduction in an acidic medium by the tip generation-substrate collection mode.

    Science.gov (United States)

    Fernández, José L; Bard, Allen J

    2003-07-01

    The oxygen reduction reaction (ORR) in acidic medium was studied on different electrode materials by scanning electrochemical microscopy (SECM) operating in a new variation of the tip generation-substrate collection mode. An ultramicroelectrode tip placed close to the substrate electrode oxidizes water to oxygen at a constant current. The substrate is held at a potential where the tip-generated oxygen is reduced and the resulting substrate current is measured. By changing the substrate potential, it is possible to obtain a polarization (current-potential) curve, which depends on the electrocatalytic activity of the substrate material. The main difference between this mode and the classical feedback SECM mode of operation is that the feedback diffusion process is not required for the measurement, allowing its application for studying the ORR in acidic solutions. Activity-sensitive images of heterogeneous surfaces, e.g., with Pt and Au electrodes, were obtained from the substrate current when the x-y plane was scanned with the tip. The usefulness of this technique for imaging electrocatalytic activity of smooth metallic electrodes and of highly dispersed fuel cell-type electrocatalysts was demonstrated. The application of this method to the combinatorial chemical analysis of electrode materials and electrocatalysts is discussed.

  15. Nonlinear Dynamics of Cantilever-Sample Interactions in Atomic Force Microscopy

    Science.gov (United States)

    Cantrell, John H.; Cantrell, Sean A.

    2010-01-01

    The interaction of the cantilever tip of an atomic force microscope (AFM) with the sample surface is obtained by treating the cantilever and sample as independent systems coupled by a nonlinear force acting between the cantilever tip and a volume element of the sample surface. The volume element is subjected to a restoring force from the remainder of the sample that provides dynamical equilibrium for the combined systems. The model accounts for the positions on the cantilever of the cantilever tip, laser probe, and excitation force (if any) via a basis set of set of orthogonal functions that may be generalized to account for arbitrary cantilever shapes. The basis set is extended to include nonlinear cantilever modes. The model leads to a pair of coupled nonlinear differential equations that are solved analytically using a matrix iteration procedure. The effects of oscillatory excitation forces applied either to the cantilever or to the sample surface (or to both) are obtained from the solution set and applied to the to the assessment of phase and amplitude signals generated by various acoustic-atomic force microscope (A-AFM) modalities. The influence of bistable cantilever modes of on AFM signal generation is discussed. The effects on the cantilever-sample surface dynamics of subsurface features embedded in the sample that are perturbed by surface-generated oscillatory excitation forces and carried to the cantilever via wave propagation are accounted by the Bolef-Miller propagating wave model. Expressions pertaining to signal generation and image contrast in A-AFM are obtained and applied to amplitude modulation (intermittent contact) atomic force microscopy and resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM). The influence of phase accumulation in A-AFM on image contrast is discussed, as is the effect of hard contact and maximum nonlinearity regimes of A-AFM operation.

  16. Tip radius preservation for high resolution imaging in amplitude modulation atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ramos, Jorge R., E-mail: jorge.rr@cea.cu [Instituto de Ciencia de Materiales de Madrid, Sor Juana Inés de la Cruz 3, Canto Blanco, 28049 Madrid, España (Spain)

    2014-07-28

    The acquisition of high resolution images in atomic force microscopy (AFM) is correlated to the cantilever's tip shape, size, and imaging conditions. In this work, relative tip wear is quantified based on the evolution of a direct experimental observable in amplitude modulation atomic force microscopy, i.e., the critical amplitude. We further show that the scanning parameters required to guarantee a maximum compressive stress that is lower than the yield/fracture stress of the tip can be estimated via experimental observables. In both counts, the optimized parameters to acquire AFM images while preserving the tip are discussed. The results are validated experimentally by employing IgG antibodies as a model system.

  17. Influence of the tip mass on the tip-sample interactions in TM-AFM

    Energy Technology Data Exchange (ETDEWEB)

    Pishkenari, Hossein Nejat, E-mail: nejat@mech.sharif.edu [Nano-Robotics Laboratory, Center of Excellence in Design, Robotics and Automation, School of Mechanical Engineering, Sharif University of Technology, Tehran, P.O. Box 11365-9465 (Iran, Islamic Republic of); Meghdari, Ali [Nano-Robotics Laboratory, Center of Excellence in Design, Robotics and Automation, School of Mechanical Engineering, Sharif University of Technology, Tehran, P.O. Box 11365-9465 (Iran, Islamic Republic of)

    2011-07-15

    This paper focuses on the influences of the tip mass ratio (the ratio of the tip mass to the cantilever mass), on the excitation of higher oscillation eigenmodes and also on the tip-sample interaction forces in tapping mode atomic force microscopy (TM-AFM). A precise model for the cantilever dynamics capable of accurate simulations is essential for the investigation of the tip mass effects on the interaction forces. In the present work, the finite element method (FEM) is used for modeling the AFM cantilever to consider the oscillations of higher eigenmodes oscillations. In addition, molecular dynamics (MD) is used to calculate precise data for the tip-sample force as a function of tip vertical position with respect to the sample. The results demonstrate that in the presence of nonlinear tip-sample interaction forces, the tip mass ratio plays a significant role in the excitations of higher eigenmodes and also in the normal force applied on the surface. Furthermore, it has been shown that the difference between responses of the FEM and point-mass models in different system operational conditions is highly affected by the tip mass ratio. -- Highlights: {yields} A strong correlation exists between the tip mass ratio and the 18th harmonic amplitude. {yields} Near the critical tip mass ratio a small change in the tip mass may lead to a significant force change. {yields} Inaccuracy of the lumped model depends significantly on the tip mass ratio.

  18. Design of a micro-cartridge system for the robotic assembly of exchangeable AFM-probe tips

    DEFF Research Database (Denmark)

    Bartenwerfer, Malte; Eichhorn, Volkmar; Fatikow, Sergej

    2013-01-01

    demand an even higher lateral resolution of the measurements. The atomic force microscope (AFM) is a common tool for this characterization and a standard instrument for all kinds of research and development disciplines. However, the characterization of three dimensional high-aspect ratio and sidewall...... structures remains a hardly accomplishable task. Novel exchangeable and customizable scanning probe tips, so-called NanoBits, can be attached to standard AFM cantilevers offering unprecedented freedom in adapting the shape and size of the tips to the surface topology of the specific application. The ultimate...

  19. Graphene cantilever under Casimir force

    Science.gov (United States)

    Derras-Chouk, Amel; Chudnovsky, Eugene M.; Garanin, Dmitry A.; Jaafar, Reem

    2018-05-01

    The stability of graphene cantilever under Casimir attraction to an underlying conductor is investigated. The dependence of the instability threshold on temperature and flexural rigidity is obtained. Analytical work is supplemented by numerical computation of the critical temperature above which the graphene cantilever irreversibly bends down and attaches to the conductor. The geometry of the attachment and exfoliation of the graphene sheet is discussed. It is argued that graphene cantilever can be an excellent tool for precision measurements of the Casimir force.

  20. GaAs/AlAs/InGaP heterostructure: a versatile material basis for cantilever designs

    International Nuclear Information System (INIS)

    Gregušová, Dagmar; Kúdela, Róbert; Eliáš, Peter; Šoltýs, Ján; Cambel, Vladimír; Kostič, Ivan

    2010-01-01

    We report on the design, fabrication and initial mechanical testing of cantilevers with tips based on a GaAs/In 0.485 Ga 0.515 P/AlAs heterostructure grown by metal organic chemical vapor deposition. They were produced using a dedicated technological process based on (1) the formation of integrated tips through an AlAs-assisted surface sacrificial wet-etching process and (2) the GaAs cantilever release fully protected between two InGaP etch-stop layers. 2 µm thick InGaP/GaAs/InGaP cantilevers had integrated pyramidal tips with the sides at ∼45° to (1 0 0). Metallic elements were processed close to the tip apexes using non-standard optical lithography. The cantilever release was accomplished using photolithography, Ar ion milling of InGaP and wet chemical etching of GaAs via resist layers deposited by a draping technique. A tip–cantilever prototype with length, width and thickness of 150, 35 and 2 µm, respectively, exhibited a resonance frequency of 66.2 kHz, which correlated well with a theoretical value of 57 kHz for a GaAs cantilever of identical dimensions. (technical note)

  1. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    NARCIS (Netherlands)

    A. Mendrik (Adrienne); E.J.P.A. Vonken; B.T.J. van Ginneken (Berbke); J.R. Riordan (John ); H.W.A.M. de Jong (Hugo); T. van Seeters (Tom); E.J. Smit (Ewoud); M.A. Viergever (Max); M. Prokop (Mathias)

    2011-01-01

    textabstractCerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of

  2. Three-phase bone scan and indium white blood cell scintigraphy following porous coated hip arthroplasty: A prospective study of the prosthetic tip

    International Nuclear Information System (INIS)

    Oswald, S.G.; Van Nostrand, D.; Savory, C.G.; Callaghan, J.J.

    1989-01-01

    Although few reports address the use of three-phase bone scanning (TPBS) and 111 In-labeled white blood cell (In-WBC) scintigraphy in hip arthroplasty utilizing a porous coated prosthesis, the literature suggests that scintigraphic patterns in the uncomplicated patient may differ from that seen in the cemented prosthesis. In an attempt to determine the scintigraphic natural history, 25 uncomplicated porous coated hip arthroplasties in 21 patients were prospectively studied with serial TPBS and In-WBC at approximately 7 days, and at 3, 6, 12, 18, and 24 mo postoperatively. This report deals with findings related to the prosthetic tip. Only one of 136 flow studies were abnormal and only two of 136 blood-pool images demonstrated focally increased activity. All 25 prostheses (120 of 143 scans) demonstrated increased uptake on the bone phase images. The area about the tip was divided into three segments; increased uptake at 24 mo was noted in the medial, distal, and lateral segments in 16%, 72%, and 56% of prostheses, respectively. Twenty of 25 prostheses (82 of 142 scans) showed uptake on In-WBC scintigraphy, being noted in 48% of prostheses at 24 mo. We conclude that scintigraphic patterns in the uncomplicated patient with a porous coated prosthesis appear to differ from patterns described in cemented prostheses

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  4. The importance of cantilever dynamics in the interpretation of Kelvin probe force microscopy.

    Science.gov (United States)

    Satzinger, Kevin J; Brown, Keith A; Westervelt, Robert M

    2012-09-15

    A realistic interpretation of the measured contact potential difference (CPD) in Kelvin probe force microscopy (KPFM) is crucial in order to extract meaningful information about the sample. Central to this interpretation is a method to include contributions from the macroscopic cantilever arm, as well as the cone and sharp tip of a KPFM probe. Here, three models of the electrostatic interaction between a KPFM probe and a sample are tested through an electrostatic simulation and compared with experiment. In contrast with previous studies that treat the KPFM cantilever as a rigid object, we allow the cantilever to bend and rotate; accounting for cantilever bending provides the closest agreement between theory and experiment. We demonstrate that cantilever dynamics play a major role in CPD measurements and provide a simulation technique to explore this phenomenon.

  5. Potential of interferometric cantilever detection and its application for SFM/AFM in liquids

    Energy Technology Data Exchange (ETDEWEB)

    Hoogenboom, B W [London Centre for Nanotechnology and Department of Physics and Astronomy, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom); Frederix, P L T M; Engel, A [M E Mueller Institute, Biozentrum, University of Basel, Klingelbergstrasse 70, 4056 Basel (Switzerland); Fotiadis, D [Institute of Biochemistry and Molecular Medicine, University of Berne, Buehlstrasse 28, 3012 Berne (Switzerland); Hug, H J [Swiss Federal Laboratories for Materials Testing and Research, EMPA, Ueberlandstrasse 129, 8600 Duebendorf (Switzerland)], E-mail: b.hoogenboom@ucl.ac.uk

    2008-09-24

    We have developed an optical cantilever deflection detector with a spot size <3 {mu}m and fm Hz{sup -1/2} sensitivity over a>10 MHz bandwidth. In this work, we demonstrate its potential for detecting small-amplitude oscillations of various flexural and torsional oscillation modes of cantilevers. The high deflection sensitivity of the interferometer is particularly useful for detecting cantilever oscillations in aqueous solutions, enabling us to reach the thermal noise limit in scanning or atomic force microscopy experiments with stiff cantilevers. This has resulted in atomic-resolution images of solid-liquid interfaces and submolecular-resolution images of native membranes.

  6. Potential of interferometric cantilever detection and its application for SFM/AFM in liquids

    International Nuclear Information System (INIS)

    Hoogenboom, B W; Frederix, P L T M; Engel, A; Fotiadis, D; Hug, H J

    2008-01-01

    We have developed an optical cantilever deflection detector with a spot size -1/2 sensitivity over a>10 MHz bandwidth. In this work, we demonstrate its potential for detecting small-amplitude oscillations of various flexural and torsional oscillation modes of cantilevers. The high deflection sensitivity of the interferometer is particularly useful for detecting cantilever oscillations in aqueous solutions, enabling us to reach the thermal noise limit in scanning or atomic force microscopy experiments with stiff cantilevers. This has resulted in atomic-resolution images of solid-liquid interfaces and submolecular-resolution images of native membranes

  7. Biosensors based on cantilevers.

    Science.gov (United States)

    Alvarez, Mar; Carrascosa, Laura G; Zinoviev, Kiril; Plaza, Jose A; Lechuga, Laura M

    2009-01-01

    Microcantilevers based-biosensors are a new label-free technique that allows the direct detection of biomolecular interactions in a label-less way and with great accuracy by translating the biointeraction into a nanomechanical motion. Low cost and reliable standard silicon technologies are widely used for the fabrication of cantilevers with well-controlled mechanical properties. Over the last years, the number of applications of these sensors has shown a fast growth in diverse fields, such as genomic or proteomic, because of the biosensor flexibility, the low sample consumption, and the non-pretreated samples required. In this chapter, we report a dedicated design and a fabrication process of highly sensitive microcantilever silicon sensors. We will describe as well an application of the device in the environmental field showing the immunodetection of an organic toxic pesticide as an example. The cantilever biofunctionalization process and the subsequent pesticide determination are detected in real time by monitoring the nanometer-scale bending of the microcantilever due to a differential surface stress generated between both surfaces of the device.

  8. System identification and control parameter optimization for a stylus profiler with exchangeable cantilevers

    OpenAIRE

    Felix Ströer; Katharina Trinkaus; Indek Raid; Jörg Seewig

    2018-01-01

    Stylus instruments are widely used in production metrology due to their robustness. Interchangeable cantilevers allow a wide range of measuring tasks to be covered with one measuring device. When approaching the sample, the positioning of the stylus instrument tip relative to the measurement object has to be accomplished in a controlled way in order to prevent damages to the specimen and the stylus cantilever. This is achieved by a closed-loop control. We present a method for the objective de...

  9. System identification and control parameter optimization for a stylus profiler with exchangeable cantilevers

    Directory of Open Access Journals (Sweden)

    Felix Ströer

    2018-02-01

    Full Text Available Stylus instruments are widely used in production metrology due to their robustness. Interchangeable cantilevers allow a wide range of measuring tasks to be covered with one measuring device. When approaching the sample, the positioning of the stylus instrument tip relative to the measurement object has to be accomplished in a controlled way in order to prevent damages to the specimen and the stylus cantilever. This is achieved by a closed-loop control. We present a method for the objective description of the stylus cantilever dynamics with system-theoretical techniques and show a simple iterative approach to optimize closed-loop control parameters with boundary conditions.

  10. Chemical sensor with oscillating cantilevered probe

    Science.gov (United States)

    Adams, Jesse D

    2013-02-05

    The invention provides a method of detecting a chemical species with an oscillating cantilevered probe. A cantilevered beam is driven into oscillation with a drive mechanism coupled to the cantilevered beam. A free end of the oscillating cantilevered beam is tapped against a mechanical stop coupled to a base end of the cantilevered beam. An amplitude of the oscillating cantilevered beam is measured with a sense mechanism coupled to the cantilevered beam. A treated portion of the cantilevered beam is exposed to the chemical species, wherein the cantilevered beam bends when exposed to the chemical species. A second amplitude of the oscillating cantilevered beam is measured, and the chemical species is determined based on the measured amplitudes.

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

    Science.gov (United States)

    Shih, Hua-Ju; Shih, Po-Jen

    2015-07-28

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

  12. Analysis the effect of different geometries of AFM's cantilever on the dynamic behavior and the critical forces of three-dimensional manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Korayem, Moharam Habibnejad, E-mail: hkorayem@iust.ac.ir; Saraie, Maniya B.; Saraee, Mahdieh B.

    2017-04-15

    An important challenge when using an atomic force microscope (AFM) is to be able to control the force exerted by the AFM for performing various tasks. Nevertheless, the exerted force is proportional to the deflection of the AFM cantilever, which itself is affected by a cantilever's stiffness coefficient. Many papers have been published so far on the methods of obtaining the stiffness coefficients of AFM cantilevers in 2D; however, a comprehensive model is yet to be presented on 3D cantilever motion. The discrepancies between the equations of the 2D and 3D analysis are due to the number and direction of forces and moments that are applied to a cantilever. Moreover, in the 3D analysis, contrary to the 2D analysis, due to the interaction between the forces and moments applied on a cantilever, its stiffness values cannot be separately expressed for each direction; and instead, a stiffness matrix should be used to correctly derive the relevant equations. In this paper, 3D stiffness coefficient matrices have been obtained for three common cantilever geometries including the rectangular, V-shape and dagger-shape cantilevers. The obtained equations are validated by two methods. In the first approach, the Finite Element Method is combined with the cantilever deflection values computed by using the obtained stiffness matrices. In the second approach, by reducing the problem's parameters, the forces applied on a cantilever along different directions are compared with each other in 2D and 3D cases. Then the 3D manipulation of a stiff nanoparticle is modeled and simulated by using the stiffness matrices obtained for the three cantilever geometries. The obtained results indicate that during the manipulation process, the dagger-shaped and rectangular cantilevers exert the maximum and minimum amounts of forces on the stiff nanoparticle, respectively. Also, by examining the effects of different probe tip geometries, it is realized that a probe tip of cylindrical geometry

  13. Analysis the effect of different geometries of AFM's cantilever on the dynamic behavior and the critical forces of three-dimensional manipulation

    International Nuclear Information System (INIS)

    Korayem, Moharam Habibnejad; Saraie, Maniya B.; Saraee, Mahdieh B.

    2017-01-01

    An important challenge when using an atomic force microscope (AFM) is to be able to control the force exerted by the AFM for performing various tasks. Nevertheless, the exerted force is proportional to the deflection of the AFM cantilever, which itself is affected by a cantilever's stiffness coefficient. Many papers have been published so far on the methods of obtaining the stiffness coefficients of AFM cantilevers in 2D; however, a comprehensive model is yet to be presented on 3D cantilever motion. The discrepancies between the equations of the 2D and 3D analysis are due to the number and direction of forces and moments that are applied to a cantilever. Moreover, in the 3D analysis, contrary to the 2D analysis, due to the interaction between the forces and moments applied on a cantilever, its stiffness values cannot be separately expressed for each direction; and instead, a stiffness matrix should be used to correctly derive the relevant equations. In this paper, 3D stiffness coefficient matrices have been obtained for three common cantilever geometries including the rectangular, V-shape and dagger-shape cantilevers. The obtained equations are validated by two methods. In the first approach, the Finite Element Method is combined with the cantilever deflection values computed by using the obtained stiffness matrices. In the second approach, by reducing the problem's parameters, the forces applied on a cantilever along different directions are compared with each other in 2D and 3D cases. Then the 3D manipulation of a stiff nanoparticle is modeled and simulated by using the stiffness matrices obtained for the three cantilever geometries. The obtained results indicate that during the manipulation process, the dagger-shaped and rectangular cantilevers exert the maximum and minimum amounts of forces on the stiff nanoparticle, respectively. Also, by examining the effects of different probe tip geometries, it is realized that a probe tip of cylindrical geometry exerts the

  14. Bi-harmonic cantilever design for improved measurement sensitivity in tapping-mode atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Loganathan, Muthukumaran; Bristow, Douglas A., E-mail: dbristow@mst.edu [Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65401 (United States)

    2014-04-15

    This paper presents a method and cantilever design for improving the mechanical measurement sensitivity in the atomic force microscopy (AFM) tapping mode. The method uses two harmonics in the drive signal to generate a bi-harmonic tapping trajectory. Mathematical analysis demonstrates that the wide-valley bi-harmonic tapping trajectory is as much as 70% more sensitive to changes in the sample topography than the standard single-harmonic trajectory typically used. Although standard AFM cantilevers can be driven in the bi-harmonic tapping trajectory, they require large forcing at the second harmonic. A design is presented for a bi-harmonic cantilever that has a second resonant mode at twice its first resonant mode, thereby capable of generating bi-harmonic trajectories with small forcing signals. Bi-harmonic cantilevers are fabricated by milling a small cantilever on the interior of a standard cantilever probe using a focused ion beam. Bi-harmonic drive signals are derived for standard cantilevers and bi-harmonic cantilevers. Experimental results demonstrate better than 30% improvement in measurement sensitivity using the bi-harmonic cantilever. Images obtained through bi-harmonic tapping exhibit improved sharpness and surface tracking, especially at high scan speeds and low force fields.

  15. Bi-harmonic cantilever design for improved measurement sensitivity in tapping-mode atomic force microscopy.

    Science.gov (United States)

    Loganathan, Muthukumaran; Bristow, Douglas A

    2014-04-01

    This paper presents a method and cantilever design for improving the mechanical measurement sensitivity in the atomic force microscopy (AFM) tapping mode. The method uses two harmonics in the drive signal to generate a bi-harmonic tapping trajectory. Mathematical analysis demonstrates that the wide-valley bi-harmonic tapping trajectory is as much as 70% more sensitive to changes in the sample topography than the standard single-harmonic trajectory typically used. Although standard AFM cantilevers can be driven in the bi-harmonic tapping trajectory, they require large forcing at the second harmonic. A design is presented for a bi-harmonic cantilever that has a second resonant mode at twice its first resonant mode, thereby capable of generating bi-harmonic trajectories with small forcing signals. Bi-harmonic cantilevers are fabricated by milling a small cantilever on the interior of a standard cantilever probe using a focused ion beam. Bi-harmonic drive signals are derived for standard cantilevers and bi-harmonic cantilevers. Experimental results demonstrate better than 30% improvement in measurement sensitivity using the bi-harmonic cantilever. Images obtained through bi-harmonic tapping exhibit improved sharpness and surface tracking, especially at high scan speeds and low force fields.

  16. Design and fabrication of a micro PZT cantilever array actuator for applications in fluidic systems

    DEFF Research Database (Denmark)

    Kim, H.; In, C.; Yoon, Gil Ho

    2005-01-01

    In this article, a micro cantilever array actuated by PZT films is designed and fabricated for micro fluidic systems. The design features for maximizing tip deflections and minimizing fluid leakage are described. The governing equation of the composite PZT cantilever is derived and the actuating......, dielectric constant, and dielectric loss. Tip deflections of 12 mu m at 5 V are measured, which agreed well with the predicted value. The 18 mu l/s leakage rate of air was observed at a pressure difference of 1000 Pa. Micro cooler is introduced, and its possible application to micro compressor is discussed....

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

    Science.gov (United States)

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

    2006-09-01

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

  18. Dual frequency modulation with two cantilevers in series: a possible means to rapidly acquire tip–sample interaction force curves with dynamic AFM

    International Nuclear Information System (INIS)

    Solares, Santiago D; Chawla, Gaurav

    2008-01-01

    One common application of atomic force microscopy (AFM) is the acquisition of tip–sample interaction force curves. However, this can be a slow process when the user is interested in studying non-uniform samples, because existing contact- and dynamic-mode methods require that the measurement be performed at one fixed surface point at a time. This paper proposes an AFM method based on dual frequency modulation using two cantilevers in series, which could be used to measure the tip–sample interaction force curves and topography of the entire sample with a single surface scan, in a time that is comparable to the time needed to collect a topographic image with current AFM imaging modes. Numerical simulation results are provided along with recommended parameters to characterize tip–sample interactions resembling those of conventional silicon tips and carbon nanotube tips tapping on silicon surfaces

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

    DEFF Research Database (Denmark)

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

    2007-01-01

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

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

    International Nuclear Information System (INIS)

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

    2007-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-01

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

  2. Finite-Element Simulation of Cantilever Vibrations in Atomic Force Acoustic Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Beltran, F J Espinoza [Centro de Investigacion y Estudios Avanzados del IPN. Unidad Queretaro, Apdo. Postal 1-798, 76001 Queretaro, Qro. (Mexico); Scholz, T [Hamburg University of Technology, Institute of Advanced Ceramics, Denickestrasse 15, D-21073 Hamburg (Germany); Schneider, G A [Hamburg University of Technology, Institute of Advanced Ceramics, Denickestrasse 15, D-21073 Hamburg (Germany); Munoz-Saldana, J [Centro de Investigacion y Estudios Avanzados del IPN. Unidad Queretaro, Apdo. Postal 1-798, 76001 Queretaro, Qro. (Mexico); Rabe, U [Fraunhofer Institute for Non-Destructive Testing (IZFP), Bldg. E3.1, University, D-66123 Saarbruecken (Germany); Arnold, W [Fraunhofer Institute for Non-Destructive Testing (IZFP), Bldg. E3.1, University, D-66123 Saarbruecken (Germany)

    2007-03-15

    Atomic Force Acoustic Microscopy has been proven to be a powerful technique for materials characterization with nanoscale lateral resolution. This technique allows one to obtain images of elastic properties of materials. By means of spectroscopic measurements of the tip-sample contact-resonance frequencies, it is possible to obtain quantitative values of the mechanical stiffness of the sample surface. For quantitative analysis a reliable relation between the spectroscopic data and the contact stiffness is required based on a correct geometrical model of the cantilever vibrations. This model must be precise enough for predicting the resonance frequencies of the tip-sample interaction when excited over a wide range of frequencies. Analytical models have served as a good reference for understanding the vibrational behavior of the AFM cantilever. They have certain limits, however, for reproducing the tip-sample contact-resonances due to the cantilever geometries used. For obtaining the local elastic modulus of samples, it is necessary to know the tip-sample contact area which is usually obtained by a calibration procedure with a reference sample. In this work we show that finiteelement modeling may be used to replace the analytical inversion procedure for AFAM data. First, the three first bending modes of cantilever resonances were used for finding the geometrical dimension of the cantilever employed. Then the normal and in-plane stiffness of the sample were obtained for each measurement on the surface to be measured. A calibration was needed to obtain the tip position of the cantilever by making measurements on a sample with known surface elasticity, here crystalline silicon. The method developed in this work was applied to AFAM measurements on silicon, zerodur, and strontium titanate.

  3. Cantilever contribution to the total electrostatic force measured with the atomic force microscope

    International Nuclear Information System (INIS)

    Guriyanova, Svetlana; Golovko, Dmytro S; Bonaccurso, Elmar

    2010-01-01

    The atomic force microscope (AFM) is a powerful tool for surface imaging at the nanometer scale and surface force measurements in the piconewton range. Among long-range surface forces, the electrostatic forces play a predominant role. They originate if the electric potentials of the substrate and of the tip of the AFM cantilever are different. A quantitative interpretation of the AFM signal is often difficult because it depends in a complicated fashion on the cantilever–tip–surface geometry. Since the electrostatic interaction is a long-range interaction, the cantilever, which is many microns from the surface, contributes to the total electrostatic force along with the tip. Here we present results of the electrostatic interaction between a conducting flat surface and horizontal or tilted cantilevers, with and without tips, at various distances from the surface. As addressed in a previous work, we show that the contribution of the cantilever to the overall force cannot be neglected. Based on a predictive model and on 3D confocal measurements, we discuss the influence of the tilting angle of the cantilever

  4. The effects of substrate layer thickness on piezoelectric vibration energy harvesting with a bimorph type cantilever

    Science.gov (United States)

    Palosaari, Jaakko; Leinonen, Mikko; Juuti, Jari; Jantunen, Heli

    2018-06-01

    In this research four piezoelectric bimorph type cantilevers for energy harvesting were manufactured, measured and analyzed to study the effects of substrate layer thickness on energy harvesting efficiency and durability under different accelerations. The cantilevers had the same dimensions of the piezoelectric ceramic components, but had different thicknesses of the steel substrate (no steel, 30 μm, 50 μm and 75 μm). The cantilevers were tuned to the same resonance frequency with different sizes of tip mass (2.13 g, 3.84 g, 4.17 g and 5.08 g). The energy harvester voltage outputs were then measured across an electrical load near to the resonance frequency (∼40 Hz) with sinusoidal vibrations under different accelerations. The stress exhibited by the four cantilevers was compared and analyzed and their durability was tested with accelerations up to 2.5 g-forces.

  5. Minimizing tip-sample forces in jumping mode atomic force microscopy in liquid

    Energy Technology Data Exchange (ETDEWEB)

    Ortega-Esteban, A. [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Horcas, I. [Nanotec Electronica S.L., Centro Empresarial Euronova 3, Ronda de Poniente 12, 28760 Tres Cantos, Madrid (Spain); Hernando-Perez, M. [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Ares, P. [Nanotec Electronica S.L., Centro Empresarial Euronova 3, Ronda de Poniente 12, 28760 Tres Cantos, Madrid (Spain); Perez-Berna, A.J.; San Martin, C.; Carrascosa, J.L. [Centro Nacional de Biotecnologia (CNB-CSIC), Darwin 3, 28049 Madrid (Spain); Pablo, P.J. de [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Gomez-Herrero, J., E-mail: julio.gomez@uam.es [Departamento de Fisica de la Materia Condensada, C-3, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2012-03-15

    Control and minimization of tip-sample interaction forces are imperative tasks to maximize the performance of atomic force microscopy. In particular, when imaging soft biological matter in liquids, the cantilever dragging force prevents identification of the tip-sample mechanical contact, resulting in deleterious interaction with the specimen. In this work we present an improved jumping mode procedure that allows detecting the tip-sample contact with high accuracy, thus minimizing the scanning forces ({approx}100 pN) during the approach cycles. To illustrate this method we report images of human adenovirus and T7 bacteriophage particles which are prone to uncontrolled modifications when using conventional jumping mode. -- Highlights: Black-Right-Pointing-Pointer Improvement in atomic force microscopy in buffer solution. Black-Right-Pointing-Pointer Peak force detection. Black-Right-Pointing-Pointer Subtracting the cantilever dragging force. Black-Right-Pointing-Pointer Forces in the 100 pN range. Black-Right-Pointing-Pointer Imaging of delicate viruses with atomic force microscopy.

  6. Analysis of heat transfer in the water meniscus at the tip-sample contact in scanning thermal microscopy

    International Nuclear Information System (INIS)

    Assy, Ali; Lefèvre, Stéphane; Chapuis, Pierre-Olivier; Gomès, Séverine

    2014-01-01

    Quantitative measurements of local nanometer-scale thermal measurements are difficult to achieve because heat flux may be transferred from the heated sensor to the cold sample through various elusive mixed thermal channels. This paper addresses one of these channels, the water meniscus at the nano-contact between a heated atomic force microscopy probe and a hydrophilic sample. This heat transfer mechanism is found to depend strongly on the probe temperature. The analysis of the pull-off forces as a function of temperature indicates that the water film almost vanishes above a probe mean temperature between 120 and 150 ºC. In particular, a methodology that allows for correlating the thermal conductance of the water meniscus to the capillary forces is applied. In the case of the standard scanning thermal microscopy Wollaston probe, values of this thermal conductance show that the water meniscus mechanism is not dominant in the thermal interaction between the probe and the sample, regardless of probe temperature. (fast track communication)

  7. An atomic force microscope for the study of the effects of tip sample interactions on dimensional metrology

    Science.gov (United States)

    Yacoot, Andrew; Koenders, Ludger; Wolff, Helmut

    2007-02-01

    An atomic force microscope (AFM) has been developed for studying interactions between the AFM tip and the sample. Such interactions need to be taken into account when making quantitative measurements. The microscope reported here has both the conventional beam deflection system and a fibre optical interferometer for measuring the movement of the cantilever. Both can be simultaneously used so as to not only servo control the tip movements, but also detect residual movement of the cantilever. Additionally, a high-resolution homodyne differential optical interferometer is used to measure the vertical displacement between the cantilever holder and the sample, thereby providing traceability for vertical height measurements. The instrument is compatible with an x-ray interferometer, thereby facilitating high resolution one-dimensional scans in the X-direction whose metrology is based on the silicon d220 lattice spacing (0.192 nm). This paper concentrates on the first stage of the instrument's development and presents some preliminary results validating the instrument's performance and showing its potential.

  8. Cantilever-like micromechanical sensors

    DEFF Research Database (Denmark)

    Boisen, Anja; Dohn, Søren; Keller, Stephan Sylvest

    2011-01-01

    The field of cantilever-based sensing emerged in the mid-1990s and is today a well-known technology for label-free sensing which holds promise as a technique for cheap, portable, sensitive and highly parallel analysis systems. The research in sensor realization as well as sensor applications has...... increased significantly over the past 10 years. In this review we will present the basic modes of operation in cantilever-like micromechanical sensors and discuss optical and electrical means for signal transduction. The fundamental processes for realizing miniaturized cantilevers are described with focus...... on silicon-and polymer-based technologies. Examples of recent sensor applications are given covering such diverse fields as drug discovery, food diagnostics, material characterizations and explosives detection....

  9. Electronically droplet energy harvesting using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud Al; Jabbour, Ghassan E.

    2012-01-01

    A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films

  10. Search for the optimally suited cantilever type for high-frequency MFM

    International Nuclear Information System (INIS)

    Koblischka, M R; Wei, J D; Kirsch, M; Lessel, M; Pfeifer, R; Brust, M; Hartmann, U; Richter, C; Sulzbach, T

    2007-01-01

    To optimize the performance of the high-frequency MFM (HF-MFM) technique [1-4], we performed a search for the best suited cantilever type and magnetic material coating. Using a HF-MFM setup with hard disk writer poles as test samples, we carried out HF-MFM imaging at frequencies up to 2 GHz. For HF-MFM, it is an essential ingredient that the tip material can follow the fast switching of the high-frequency fields. In this contribution, we investigated 6 different types of cantilevers (i) the 'standard' MFM tip (Nanoworld Pointprobe) with 30 nm CoCr coating, (ii) a 'SSS' (Nanoworld SuperSharpSilicon TM ) cantilever with a 10 nm CoCr coating, (iii) a (Ni, Zn)-ferrite coated pointprobe tip (iv) a Ba 3 Co 2 Fe 23 O 41 (BCFO) coated pointprobe tip, (v) a low-coercivity NiCo alloy coated tip, and (vi) a permalloy-coated tip

  11. Tips for TIPS

    NARCIS (Netherlands)

    Cuijpers, C.F.

    2015-01-01

    The transjugular intrahepatic portosystemic shunt (TIPS) procedure is one of the most technically challenging procedures in interventional radiology. During the procedure, interventional radiologists (IRs) insert very thin and long instruments through a little incision in the patient’s neck. They

  12. Experimental measurements of out-of-plane vibrations of a simple blisk design using Blade Tip Timing and Scanning LDV measurement methods

    Science.gov (United States)

    Di Maio, D.; Ewins, D. J.

    2012-04-01

    The study of dynamic properties of rotating structures, such as bladed discs, can be conveniently done using simple bladed discs where the blades do not have staggering angles. Simplified design, although not truly representative of real structures, can be easy and economic to manufacture and, still, very helpful for studying specific dynamic properties. An example of this can be called as mass mistune blisk study. Experimental measurements of vibrations of bladed discs under rotating conditions can be performed using Scanning Laser Doppler Vibrometer (SLDV) systems. However, in the aerospace industry, the vibrations of complex bladed discs must be measured under operating conditions which are more hostile than laboratory simulations. The Blade Tip Timing (BTT) measurement method is a measurement technique, which can be used to measure vibrations of bladed discs of an engine aircraft under operating conditions. However, the BTT technique is ineffective when used with a flat bladed disc whose blade vibrations cannot be measured. This can be detrimental when the use of controlled dynamic parameters, such as those obtained from a simple bladed disc design, can improve the confidence for the validation of post-processing software. This paper presents a work about experimental measurements of a simple bladed disc design whose vibrations were measured synchronously by Scanning LDV and BTT measurement systems. A rotating test rig and its mechanical modifications for the installation of the BTT probes are introduced. Implications of rotating a specimen inconsistently are presented so as solutions to obtained constant revolving speed. The experimental comparisons of forced response vibrations measured synchronously at one blade are presented and explained.

  13. Polymeric Cantilever Arrays for Biosensing Applications

    DEFF Research Database (Denmark)

    Calleja, M.; Tamayo, J.; Johansson, Alicia

    2003-01-01

    We report the fabrication of arrays of polymeric cantilevers for biochemistry applications. The cantilevers are fabricated in the polymer SU-8. The use of a polymer as the component material for the cantilevers provides the sensors with very high sensitivity due to convenient mechanical material...... properties. The fabrication process is based on spin coating of the photosensitive polymer and near-ultraviolet exposure. The method allows obtaining well-controlled and uniform mechanical properties of the cantilevers. The elastic constant of the cantilevers was measured, and their dynamic response...

  14. Cantilevered probe detector with piezoelectric element

    Science.gov (United States)

    Adams, Jesse D; Sulchek, Todd A; Feigin, Stuart C

    2013-04-30

    A disclosed chemical detection system for detecting a target material, such as an explosive material, can include a cantilevered probe, a probe heater coupled to the cantilevered probe, and a piezoelectric element disposed on the cantilevered probe. The piezoelectric element can be configured as a detector and/or an actuator. Detection can include, for example, detecting a movement of the cantilevered probe or a property of the cantilevered probe. The movement or a change in the property of the cantilevered probe can occur, for example, by adsorption of the target material, desorption of the target material, reaction of the target material and/or phase change of the target material. Examples of detectable movements and properties include temperature shifts, impedance shifts, and resonant frequency shifts of the cantilevered probe. The overall chemical detection system can be incorporated, for example, into a handheld explosive material detection system.

  15. A new detection system for extremely small vertically mounted cantilevers

    International Nuclear Information System (INIS)

    Antognozzi, M; Ulcinas, A; Picco, L; Simpson, S H; Miles, M J; Heard, P J; Szczelkun, M D; Brenner, B

    2008-01-01

    Detection techniques currently used in scanning force microscopy impose limitations on the geometrical dimensions of the probes and, as a consequence, on their force sensitivity and temporal response. A new technique, based on scattered evanescent electromagnetic waves (SEW), is presented here that can detect the displacement of the extreme end of a vertically mounted cantilever. The resolution of this method is tested using different cantilever sizes and a theoretical model is developed to maximize the detection sensitivity. The applications presented here clearly show that the SEW detection system enables the use of force sensors with sub-micron size, opening new possibilities in the investigation of biomolecular systems and high speed imaging. Two types of cantilevers were successfully tested: a high force sensitivity lever with a spring constant of 0.17 pN nm -1 and a resonant frequency of 32 kHz; and a high speed lever with a spring constant of 50 pN nm -1 and a resonant frequency of 1.8 MHz. Both these force sensors were fabricated by modifying commercial microcantilevers in a focused ion beam system. It is important to emphasize that these modified cantilevers could not be detected by the conventional optical detection system used in commercial atomic force microscopes

  16. Shielded piezoresistive cantilever probes for nanoscale topography and electrical imaging

    International Nuclear Information System (INIS)

    Yang, Yongliang; Ma, Eric Yue; Cui, Yong-Tao; Lai, Keji; Kundhikanjana, Worasom; Kelly, Michael; Shen, Zhi-Xun; Haemmerli, Alexandre; Harjee, Nahid; Pruitt, Beth L

    2014-01-01

    This paper presents the design and fabrication of piezoresistive cantilever probes for microwave impedance microscopy (MIM) to enable simultaneous topographic and electrical imaging. Plasma enhanced chemical vapor deposited Si 3 N 4  cantilevers with a shielded center conductor line and nanoscale conductive tip apex are batch fabricated on silicon-on-insulator wafers. Doped silicon piezoresistors are integrated at the root of the cantilevers to sense their deformation. The piezoresistive sensitivity is 2 nm for a bandwidth of 10 kHz, enabling topographical imaging with reasonable speed. The aluminum center conductor has a low resistance (less than 5 Ω) and small capacitance (∼1.7 pF) to ground; these parameters are critical for high sensitivity MIM imaging. High quality piezoresistive topography and MIM images are simultaneously obtained with the fabricated probes at ambient and cryogenic temperatures. These new piezoresistive probes remarkably broaden the horizon of MIM for scientific applications by operating with an integrated feedback mechanism at low temperature and for photosensitive samples. (paper)

  17. Thermoelectric voltage at a nanometer-scale heated tip point contact

    Science.gov (United States)

    Fletcher, Patrick C.; Lee, Byeonghee; King, William P.

    2012-01-01

    We report thermoelectric voltage measurements between the platinum-coated tip of a heated atomic force microscope (AFM) cantilever and a gold-coated substrate. The cantilevers have an integrated heater-thermometer element made from doped single crystal silicon, and a platinum tip. The voltage can be measured at the tip, independent from the cantilever heating. We used the thermocouple junction between the platinum tip and the gold substrate to measure thermoelectric voltage during heating. Experiments used either sample-side or tip-side heating, over the temperature range 25-275 °C. The tip-substrate contact is ˜4 nm in diameter and its average measured Seebeck coefficient is 3.4 μV K-1. The thermoelectric voltage is used to determine tip-substrate interface temperature when the substrate is either glass or quartz. When the non-dimensional cantilever heater temperature is 1, the tip-substrate interface temperature is 0.593 on glass and 0.125 on quartz. Thermal contact resistance between the tip and the substrate heavily influences the tip-substrate interface temperature. Measurements agree well with modeling when the tip-substrate interface contact resistance is 108 K W-1.

  18. Protein crystals as scanned probes for recognition atomic force microscopy.

    Science.gov (United States)

    Wickremasinghe, Nissanka S; Hafner, Jason H

    2005-12-01

    Lysozyme crystal growth has been localized at the tip of a conventional silicon nitride cantilever through seeded nucleation. After cross-linking with glutaraldehyde, lysozyme protein crystal tips image gold nanoparticles and grating standards with a resolution comparable to that of conventional tips. Force spectra between the lysozyme crystal tips and surfaces covered with antilysozyme reveal an adhesion force that drops significantly upon blocking with free lysozyme, thus confirming that lysozyme crystal tips can detect molecular recognition interactions.

  19. Spin-polarized scanning tunneling microscopy experiments on the rough surface of a polycrystalline NiFe film with a fine magnetic tip sensitive to a well-defined magnetization component

    Energy Technology Data Exchange (ETDEWEB)

    Matsuyama, H., E-mail: matsu@phys.sci.hokudai.ac.jp [Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Nara, D.; Kageyama, R.; Honda, K.; Sato, T.; Kusanagi, K. [Department of Condensed Matter Physics, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Srinivasan, E. [Creative Research Institution (CRIS), Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan); Koike, K. [Department of Physics, Faculty of Science, Hokkaido University, Sapporo, Hokkaido 060-0810 (Japan); Creative Research Institution (CRIS), Hokkaido University, Sapporo, Hokkaido 001-0021 (Japan)

    2016-03-15

    We developed a micrometer-sized magnetic tip integrated onto the write head of a hard disk drive for spin-polarized scanning tunneling microscopy (SP-STM) in the modulated tip magnetization mode. Using SP-STM, we measured a well-defined in-plane spin-component of the tunneling current of the rough surface of a polycrystalline NiFe film. The spin asymmetry of the NiFe film was about 1.3% within the bias voltage range of -3 to 1 V. We obtained the local spin component image of the sample surface, switching the magnetic field of the sample to reverse the sample magnetization during scanning. We also obtained a spin image of the rough surface of a polycrystalline NiFe film evaporated on the recording medium of a hard disk drive.

  20. Spin-polarized scanning tunneling microscopy experiments on the rough surface of a polycrystalline NiFe film with a fine magnetic tip sensitive to a well-defined magnetization component

    Directory of Open Access Journals (Sweden)

    H. Matsuyama

    2016-03-01

    Full Text Available We developed a micrometer-sized magnetic tip integrated onto the write head of a hard disk drive for spin-polarized scanning tunneling microscopy (SP-STM in the modulated tip magnetization mode. Using SP-STM, we measured a well-defined in-plane spin-component of the tunneling current of the rough surface of a polycrystalline NiFe film. The spin asymmetry of the NiFe film was about 1.3% within the bias voltage range of -3 to 1 V. We obtained the local spin component image of the sample surface, switching the magnetic field of the sample to reverse the sample magnetization during scanning. We also obtained a spin image of the rough surface of a polycrystalline NiFe film evaporated on the recording medium of a hard disk drive.

  1. Tipping Point

    Medline Plus

    Full Text Available ... death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash ... tv tip-overs. The force of a large television falling from tipping furniture can be staggering. A ...

  2. CPAP Tips

    Science.gov (United States)

    ... now Try it free Find out why Close CPAP Tips from FDA USFoodandDrugAdmin Loading... Unsubscribe from USFoodandDrugAdmin? ... apnea and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from ...

  3. Tipping Point

    Medline Plus

    Full Text Available ... and furniture, appliance and tv tip-overs. The force of a large television falling from tipping furniture ... 50 lb. TV falls with about the same force as child falling from the third story of ...

  4. Tipping Point

    Medline Plus

    Full Text Available ... Tipping Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture ... about horrible accidents involving young children and furniture, appliance and tv tip-overs. The force of a ...

  5. Tipping Point

    Medline Plus

    Full Text Available ... en español Blog About OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point The Tipping Point by ... danger death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe ...

  6. A compact atomic force-scanning tunneling microscope for studying microelectronics and environmental aerosols

    International Nuclear Information System (INIS)

    Chen, G.

    1996-06-01

    This dissertation describes the characteristics and the construction of a compact atomic force/scanning tunneling microscope (AFM/STM). The basics and the method of preparing a tunneling junction between a chemically etched tunneling tip and a micro-manufactured cantilever is outlined by analyzing the forces between tunneling tip and cantilever as well as between force-sensing tip and sample surfaces. To our best knowledge this instrument is the first one using a commercial cantilever with only one piezoelectric tube carrying the whole tunneling sensor. The feedback control system has been optimized after a careful analysis of the electronic loop characteristics. The mode of operation has been determined by analyzing the dynamic characteristics of the scan heads and by investigating the time characteristics of the data acquisition system. The vibration isolation system has been calibrated by analyzing the characteristics of the damping setup and the stiffness of the scan head. The calculated results agree well with the measured ones. Also, a software package for data acquisition and real time display as well as for image processing and three-dimensional visualization has been developed. With this home-made software package, the images can be processed by means of a convolution filter, a Wiener filter and other 2-D FFT filters, and can be displayed in different ways. Atomic resolution images of highly oriented pyrolytic graphite (HOPG) and graphite surfaces have been obtained in AFM and STM mode. New theoretical explanations have been given for the observed anomalous STM and AFM images of graphite by calculating the asymmetric distribution of quantum conductance and tip-surface forces on a graphite surface. This not only resolved the theoretical puzzles of STM and AFM of graphite, but also revealed the relation between atomic force microscopy and scanning tunneling microscopy of graphite. Applications of STM and AFM to micro-electronic devices have been investigated

  7. Investigation of static and dynamic behavior of functionally graded piezoelectric actuated Poly-Si micro cantilever probe

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Vibhuti Bhushan; Parashar, Sandeep Kumar, E-mail: skparashar@rtu.ac.in [Department of Mechanical Engineering, Rajasthan Technical University, Kota (India)

    2016-04-13

    In the present paper a novel functionally graded piezoelectric (FGP) actuated Poly-Si micro cantilever probe is proposed for atomic force microscope. The shear piezoelectric coefficient d{sub 15} has much higher value than coupling coefficients d{sub 31} and d{sub 33}, hence in the present work the micro cantilever beam actuated by d{sub 15} effect is utilized. The material properties are graded in the thickness direction of actuator by a simple power law. A three dimensional finite element analysis has been performed using COMSOL Multiphysics® (version 4.2) software. Tip deflection and free vibration analysis for the micro cantilever probe has been done. The results presented in the paper shall be useful in the design of micro cantilever probe and their subsequent utilization in atomic force microscopes.

  8. Fabrication of resonant micro cantilevers with integrated transparent fluidic channel

    DEFF Research Database (Denmark)

    Khan, Faheem; Schmid, Silvan; Davis, Zachary James

    2011-01-01

    Microfabricated cantilevers are proving their potential as excellent tools for analysis applications. In this paper, we describe the design, fabrication and testing of resonant micro cantilevers with integrated transparent fluidic channels. The cantilevers have been devised to measure the density...

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

    International Nuclear Information System (INIS)

    Liu, Bernard Haochih; Chang, Day-Bin

    2011-01-01

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

  10. Analysis of dynamic cantilever behavior in tapping mode atomic force microscopy.

    Science.gov (United States)

    Deng, Wenqi; Zhang, Guang-Ming; Murphy, Mark F; Lilley, Francis; Harvey, David M; Burton, David R

    2015-10-01

    Tapping mode atomic force microscopy (AFM) provides phase images in addition to height and amplitude images. Although the behavior of tapping mode AFM has been investigated using mathematical modeling, comprehensive understanding of the behavior of tapping mode AFM still poses a significant challenge to the AFM community, involving issues such as the correct interpretation of the phase images. In this paper, the cantilever's dynamic behavior in tapping mode AFM is studied through a three dimensional finite element method. The cantilever's dynamic displacement responses are firstly obtained via simulation under different tip-sample separations, and for different tip-sample interaction forces, such as elastic force, adhesion force, viscosity force, and the van der Waals force, which correspond to the cantilever's action upon various different representative computer-generated test samples. Simulated results show that the dynamic cantilever displacement response can be divided into three zones: a free vibration zone, a transition zone, and a contact vibration zone. Phase trajectory, phase shift, transition time, pseudo stable amplitude, and frequency changes are then analyzed from the dynamic displacement responses that are obtained. Finally, experiments are carried out on a real AFM system to support the findings of the simulations. © 2015 Wiley Periodicals, Inc.

  11. Cantilevers orthodontics forces measured by fiber sensors

    Science.gov (United States)

    Schneider, Neblyssa; Milczewski, Maura S.; de Oliveira, Valmir; Guariza Filho, Odilon; Lopes, Stephani C. P. S.; Kalinowski, Hypolito J.

    2015-09-01

    Fibers Bragg Gratings were used to evaluate the transmission of the forces generates by orthodontic mechanic based one and two cantilevers used to move molars to the upright position. The results showed levels forces of approximately 0,14N near to the root of the molar with one and two cantilevers.

  12. Cantilever sensors: Nanomechanical tools for diagnostics

    DEFF Research Database (Denmark)

    Datar, R.; Kim, S.; Jeon, S.

    2009-01-01

    Cantilever sensors have attracted considerable attention over the last decade because of their potential as a highly sensitive sensor platform for high throughput and multiplexed detection of proteins and nucleic acids. A micromachined cantilever platform integrates nanoscale science and microfab......Cantilever sensors have attracted considerable attention over the last decade because of their potential as a highly sensitive sensor platform for high throughput and multiplexed detection of proteins and nucleic acids. A micromachined cantilever platform integrates nanoscale science...... and microfabrication technology for the label-free detection of biological molecules, allowing miniaturization. Molecular adsorption, when restricted to a single side of a deformable cantilever beam, results in measurable bending of the cantilever. This nanoscale deflection is caused by a variation in the cantilever...... surface stress due to biomolecular interactions and can be measured by optical or electrical means, thereby reporting on the presence of biomolecules. Biological specificity in detection is typically achieved by immobilizing selective receptors or probe molecules on one side of the cantilever using...

  13. Oscillations of end loaded cantilever beams

    International Nuclear Information System (INIS)

    Macho-Stadler, E; Elejalde-García, M J; Llanos-Vázquez, R

    2015-01-01

    This article presents several simple experiments based on changing transverse vibration frequencies in a cantilever beam, when acted on by an external attached mass load at the free end. By using a mechanical wave driver, available in introductory undergraduate laboratories, we provide various experimental results for end loaded cantilever beams that fit reasonably well into a linear equation. The behaviour of the cantilever beam’s weak-damping resonance response is studied for the case of metal resonance strips. As the mass load increases, a more pronounced decrease occurs in the fundamental frequency of beam vibration. It is important to note that cantilever construction is often used in architectural design and engineering construction projects but current analysis also predicts the influence of mass load on the sound generated by musical free reeds with boundary conditions similar to a cantilever beam. (paper)

  14. Oscillations of end loaded cantilever beams

    Science.gov (United States)

    Macho-Stadler, E.; Elejalde-García, M. J.; Llanos-Vázquez, R.

    2015-09-01

    This article presents several simple experiments based on changing transverse vibration frequencies in a cantilever beam, when acted on by an external attached mass load at the free end. By using a mechanical wave driver, available in introductory undergraduate laboratories, we provide various experimental results for end loaded cantilever beams that fit reasonably well into a linear equation. The behaviour of the cantilever beam’s weak-damping resonance response is studied for the case of metal resonance strips. As the mass load increases, a more pronounced decrease occurs in the fundamental frequency of beam vibration. It is important to note that cantilever construction is often used in architectural design and engineering construction projects but current analysis also predicts the influence of mass load on the sound generated by musical free reeds with boundary conditions similar to a cantilever beam.

  15. High-speed tapping-mode atomic force microscopy using a Q-controlled regular cantilever acting as the actuator: Proof-of-principle experiments

    Energy Technology Data Exchange (ETDEWEB)

    Balantekin, M., E-mail: mujdatbalantekin@iyte.edu.tr [Electrical and Electronics Engineering, İzmir Institute of Technology, Urla, İzmir 35430 (Turkey); Satır, S.; Torello, D.; Değertekin, F. L. [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States)

    2014-12-15

    We present the proof-of-principle experiments of a high-speed actuation method to be used in tapping-mode atomic force microscopes (AFM). In this method, we do not employ a piezotube actuator to move the tip or the sample as in conventional AFM systems, but, we utilize a Q-controlled eigenmode of a cantilever to perform the fast actuation. We show that the actuation speed can be increased even with a regular cantilever.

  16. Investigation of polymer derived ceramics cantilevers for application of high speed atomic force microscopy

    Science.gov (United States)

    Wu, Chia-Yun

    High speed Atomic Force Microscopy (AFM) has a wide variety of applications ranging from nanomanufacturing to biophysics. In order to have higher scanning speed of certain AFM modes, high resonant frequency cantilevers are needed; therefore, the goal of this research is to investigate using polymer derived ceramics for possible applications in making high resonant frequency AFM cantilevers using complex cross sections. The polymer derived ceramic that will be studied, is silicon carbide. Polymer derived ceramics offer a potentially more economic fabrication approach for MEMS due to their relatively low processing temperatures and ease of complex shape design. Photolithography was used to make the desired cantilever shapes with micron scale size followed by a wet etching process to release the cantilevers from the substrates. The whole manufacturing process we use borrow well-developed techniques from the semiconducting industry, and as such this project also could offer the opportunity to reduce the fabrication cost of AFM cantilevers and MEMS in general. The characteristics of silicon carbide made from the precursor polymer, SMP-10 (Starfire Systems), were studied. In order to produce high qualities of silicon carbide cantilevers, where the major concern is defects, proper process parameters needed to be determined. Films of polymer derived ceramics often have defects due to shrinkage during the conversion process. Thus control of defects was a central issue in this study. A second, related concern was preventing oxidation; the polymer derived ceramics we chose is easily oxidized during processing. Establishing an environment without oxygen in the whole process was a significant challenge in the project. The optimization of the parameters for using photolithography and wet etching process was the final and central goal of the project; well established techniques used in microfabrication were modified for use in making the cantilever in the project. The techniques

  17. CPAP Tips

    Medline Plus

    Full Text Available ... now Try it free Find out why Close CPAP Tips from FDA USFoodandDrugAdmin Loading... Unsubscribe from USFoodandDrugAdmin? ... apnea and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from ...

  18. Technology Tips

    Science.gov (United States)

    Mathematics Teacher, 2004

    2004-01-01

    Some inexpensive or free ways that enable to capture and use images in work are mentioned. The first tip demonstrates the methods of using some of the built-in capabilities of the Macintosh and Windows-based PC operating systems, and the second tip describes methods to capture and create images using SnagIt.

  19. Tipping Point

    Medline Plus

    Full Text Available ... OnSafety CPSC Stands for Safety The Tipping Point Home > 60 Seconds of Safety (Videos) > The Tipping Point ... 24 hours a day. For young children whose home is a playground, it’s the best way to ...

  20. Tipping Point

    Medline Plus

    Full Text Available ... 60 Seconds of Safety (Videos) > The Tipping Point The Tipping Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash ...

  1. Nonlinear vibration of rectangular atomic force microscope cantilevers by considering the Hertzian contact theory

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, A., E-mail: a_sadeghi@srbiau.ac.ir [Islamic Azad Univ., Dept. of Mechanical and Aerospace Engineering, Science and Research Branch, Tehran (Iran, Islamic Republic of); Zohoor, H. [Sharif Univ. of Technology, Center of Excellence in Design, Robotics and Automation, Tehran (Iran, Islamic Republic of); The Academy of Sciences if I.R. Iran (Iran, Islamic Republic of)

    2010-05-15

    The nonlinear flexural vibration for a rectangular atomic force microscope cantilever is investigated by using Timoshenko beam theory. In this paper, the normal and tangential tip-sample interaction forces are found from a Hertzian contact model and the effects of the contact position, normal and lateral contact stiffness, tip height, thickness of the beam, and the angle between the cantilever and the sample surface on the nonlinear frequency to linear frequency ratio are studied. The differential quadrature method is employed to solve the nonlinear differential equations of motion. The results show that softening behavior is seen for most cases and by increasing the normal contact stiffness, the frequency ratio increases for the first mode, but for the second mode, the situation is reversed. The nonlinear-frequency to linear-frequency ratio increases by increasing the Timoshenko beam parameter, but decreases by increasing the contact position for constant amplitude for the first and second modes. For the first mode, the frequency ratio decreases by increasing both of the lateral contact stiffness and the tip height, but increases by increasing the angle α between the cantilever and sample surface. (author)

  2. Dual-MWCNT Probe Thermal Sensor Assembly and Evaluation Based on Nanorobotic Manipulation inside a Field-Emission-Scanning Electron Microscope

    Directory of Open Access Journals (Sweden)

    Zhan Yang

    2015-03-01

    Full Text Available We report a thermal sensor composed of two multiwalled carbon nano-tubes (MWCNTs inside a field-emission-scanning electron microscope. The sensor was assembled using a nanorobotic manipulation system, which was used to construct a probe tip in order to detect the local environment of a single cell. An atomic force microscopy (AFM cantilever was used as a substrate; the cantilever was composed of Si3N4 and both sides were covered with a gold layer. MWCNTs were individually assembled on both sides of the AFM cantilever by employing nanorobotic manipulation. Another AFM cantilever was subsequently used as an end effector to manipulate the MWCNTs to touch each other. Electron-beam-induced deposition (EBID was then used to bond the two MWCNTs. The MWCNT probe thermal sensor was evaluated inside a thermostated container in the temperature range from 25°C to 60°C. The experimental results show the positive characteristics of the temperature coefficient of resistance (TCR.

  3. Tipping Point

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    Full Text Available ... fall furniture head injury product safety television tipover tv Watch the video in Adobe Flash format. Almost ... accidents involving young children and furniture, appliance and tv tip-overs. The force of a large television ...

  4. Tipping Point

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    Full Text Available ... of a large television falling from tipping furniture can be staggering. A 50 lb. TV falls with ... story of a building. That kind of impact can kill a child or cause severe injuries. About ...

  5. Tipping Point

    Medline Plus

    Full Text Available ... Point by CPSC Blogger September 22, 2009 appliance child Childproofing CPSC danger death electrical fall furniture head ... see news reports about horrible accidents involving young children and furniture, appliance and tv tip-overs. The ...

  6. CPAP Tips

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    Full Text Available ... sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely and effectively use your CPAP device. Category Education License Standard YouTube License Show more Show ...

  7. CPAP Tips

    Medline Plus

    Full Text Available ... opinion count. Sign in ... and use a continuous positive airway pressure (CPAP) device when sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely ...

  8. Tipping Point

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    Full Text Available ... third story of a building. That kind of impact can kill a child or cause severe injuries. ... to prevent a tip-over tragedy. Share Post Facebook Twitter Google Plus Reddit Connect with Me:  Visit ...

  9. Micromechanical testing of SU-8 cantilevers

    OpenAIRE

    Hopcroft, M; Kramer, T; Kim, G; Takashima, K; Higo, Y; Moore, D; Brugger, J

    2005-01-01

    SU-8 is a photoplastic polymer with a wide range of possible applications in microtechnology. Cantilevers designed for atomic force microscopes were fabricated in SU-8. The mechanical properties of these cantilevers were investigated using two microscale testing techniques: contact surface profilometer beam deflection and static load deflection at a point on the beam using a specially designed test machine. The SU-8 Young's modulus value from the microscale test methods is approximately 2-3 GPa.

  10. Design optimization and fatigue testing of an electronically-driven mechanically-resonant cantilever spring mechanism

    International Nuclear Information System (INIS)

    Kheng, Lim Boon; Kean, Koay Loke; Gitano-Briggs, Horizon

    2010-01-01

    A light scanning device consisting of an electronically-driven mechanically-resonant cantilever spring-mirror system has been developed for innovative lighting applications. The repeated flexing of the cantilever spring during operation can lead to premature fatigue failure. A model was created to optimize the spring design. The optimized spring design can reduce stress by approximately one-third from the initial design. Fatigue testing showed that the optimized spring design can operate continuously for over 1 month without failure. Analysis of failures indicates surface cracks near the root of the spring are responsible for the failures.

  11. Optimization of the imaging response of scanning microwave microscopy measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sardi, G. M.; Lucibello, A.; Proietti, E.; Marcelli, R., E-mail: romolo.marcelli@imm.cnr.it [National Research Council, Institute for Microelectronics and Microsystems, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Kasper, M.; Gramse, G. [Biophysics Institute, Johannes Kepler University, Gruberstrasse 40, 4020 Linz (Austria); Kienberger, F. [Keysight Technologies Austria GmbH, Gruberstrasse 40, 4020 Linz (Austria)

    2015-07-20

    In this work, we present the analytical modeling and preliminary experimental results for the choice of the optimal frequencies when performing amplitude and phase measurements with a scanning microwave microscope. In particular, the analysis is related to the reflection mode operation of the instrument, i.e., the acquisition of the complex reflection coefficient data, usually referred as S{sub 11}. The studied configuration is composed of an atomic force microscope with a microwave matched nanometric cantilever probe tip, connected by a λ/2 coaxial cable resonator to a vector network analyzer. The set-up is provided by Keysight Technologies. As a peculiar result, the optimal frequencies, where the maximum sensitivity is achieved, are different for the amplitude and for the phase signals. The analysis is focused on measurements of dielectric samples, like semiconductor devices, textile pieces, and biological specimens.

  12. Optical detection of ultrasound using an apertureless near-field scanning optical microscopy system

    Science.gov (United States)

    Ahn, Phillip; Zhang, Zhen; Sun, Cheng; Balogun, Oluwaseyi

    2013-01-01

    Laser ultrasonics techniques are power approaches for non-contact generation and detection of high frequency ultrasound on a local scale. In these techniques, optical diffraction limits the spatial information that can be accessed from a measurement. In order to improve the lateral spatial resolution, we incorporate an apertureless near-field scanning optical microscope (aNSOM) into laser ultrasonics setup for local detection of laser generated ultrasound. The aNSOM technique relies on the measurement of a weak backscattered near-field light intensity resulting from the oblique illumination of a nanoscale probe-tip positioned close to a sample surface. We enhance the optical near-field intensity by coupling light to surface plasmon polaritons (SPPs) on the shaft of an atomic force microscopy (AFM) cantilever. The SPPs propagate down the AFM shaft, localize at the tip apex, and are backscattered to the far-field when the separation distance between the probe tip and the sample surface is comparable to the probe-tip radius. The backscattered near-field intensity is dynamically modulated when an ultrasonic wave arrives at the sample surface leading to a transient change in the tip-sample separation distance. We present experimental results detailing measurement of broadband and narrowband laser generated ultrasound in solids with frequencies reaching up to 180 MHz range.

  13. AFM tip-sample convolution effects for cylinder protrusions

    Science.gov (United States)

    Shen, Jian; Zhang, Dan; Zhang, Fei-Hu; Gan, Yang

    2017-11-01

    A thorough understanding about the AFM tip geometry dependent artifacts and tip-sample convolution effect is essential for reliable AFM topographic characterization and dimensional metrology. Using rigid sapphire cylinder protrusions (diameter: 2.25 μm, height: 575 nm) as the model system, a systematic and quantitative study about the imaging artifacts of four types of tips-two different pyramidal tips, one tetrahedral tip and one super sharp whisker tip-is carried out through comparing tip geometry dependent variations in AFM topography of cylinders and constructing the rigid tip-cylinder convolution models. We found that the imaging artifacts and the tip-sample convolution effect are critically related to the actual inclination of the working cantilever, the tip geometry, and the obstructive contacts between the working tip's planes/edges and the cylinder. Artifact-free images can only be obtained provided that all planes and edges of the working tip are steeper than the cylinder sidewalls. The findings reported here will contribute to reliable AFM characterization of surface features of micron or hundreds of nanometers in height that are frequently met in semiconductor, biology and materials fields.

  14. Microstructuring of piezoresistive cantilevers for gas detection and analysis

    International Nuclear Information System (INIS)

    Sarov, Y.; Sarova, V.; Bitterlich, Ch.; Richter, O.; Guliyev, E.; Zoellner, J.-P.; Rangelow, I. W.; Andok, R.; Bencurova, A.

    2011-01-01

    In this work we report on a design and fabrication of cantilevers for gas detection and analysis. The cantilevers have expanded area of interaction with the gas, while the signal transduction is realized by an integrated piezoresistive deflection sensor, placed at the narrowed cantilever base with highest stress along the cantilever. Moreover, the cantilevers have integrated bimorph micro-actuator detection in a static and dynamic mode. The cantilevers are feasible as pressure, temperature and flow sensors and under chemical functionalization - for gas recognition, tracing and composition analysis. (authors)

  15. Coalescence and movement of nanobubbles studied with tapping mode AFM and tip-bubble interaction analysis

    International Nuclear Information System (INIS)

    Bhushan, Bharat; Wang Yuliang; Maali, Abdelhamid

    2008-01-01

    Imaging of a polystyrene (PS) coated silicon wafer immersed in deionized (DI) water was conducted using atomic force microscopy (AFM) in the tapping mode (TMAFM). As reported earlier, spherical cap-like domains, referred to as nanobubbles, were observed to be distributed on the PS surface. Experiments reveal that, in addition to the well-known parameter of scan load, scan speed is also an important parameter which affects nanobubble coalescence. The process of nanobubble coalescence was studied. It was found that during coalescence, small nanobubbles were easily moved and merged into bigger ones. Based on the interaction between the AFM cantilever tip and a bubble in the so-called force modulation mode of TMAFM, bubble height and adhesive force information for a given bubble was extracted. A viscoelastic model is used to obtain the interaction stiffness and damping coefficient, which provides a method to obtain the mechanical properties of nanobubbles. The model was further used to study the effect of surface tension force on attractive interaction force and contact angle hysteresis on the changes of the interaction damping coefficient during tip-bubble interaction.

  16. Thermoelectric voltage at a nanometer-scale heated tip point contact

    International Nuclear Information System (INIS)

    Fletcher, Patrick C; Lee, Byeonghee; King, William P

    2012-01-01

    We report thermoelectric voltage measurements between the platinum-coated tip of a heated atomic force microscope (AFM) cantilever and a gold-coated substrate. The cantilevers have an integrated heater–thermometer element made from doped single crystal silicon, and a platinum tip. The voltage can be measured at the tip, independent from the cantilever heating. We used the thermocouple junction between the platinum tip and the gold substrate to measure thermoelectric voltage during heating. Experiments used either sample-side or tip-side heating, over the temperature range 25–275 °C. The tip–substrate contact is ∼4 nm in diameter and its average measured Seebeck coefficient is 3.4 μV K −1 . The thermoelectric voltage is used to determine tip–substrate interface temperature when the substrate is either glass or quartz. When the non-dimensional cantilever heater temperature is 1, the tip–substrate interface temperature is 0.593 on glass and 0.125 on quartz. Thermal contact resistance between the tip and the substrate heavily influences the tip–substrate interface temperature. Measurements agree well with modeling when the tip–substrate interface contact resistance is 10 8 K W −1 . (paper)

  17. CPAP Tips

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  18. Tipping Point

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    Full Text Available ... sleeping? Here are some tips from the U.S. Food and Drug Administration (FDA) on how to safely and effectively use your CPAP device. Category ... Ambulance Service 21,588 views 4:34 Obstructive Sleep Apnea ...

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  2. Nonlinear mathematical modeling of vibrating motion of nanomechanical cantilever active probe

    Directory of Open Access Journals (Sweden)

    Reza Ghaderi

    Full Text Available Nonlinear vibration response of nanomechanical cantilever (NMC active probes in atomic force microscope (AFM application has been studied in the amplitude mode. Piezoelectric layer is placed piecewise and as an actuator on NMC. Continuous beam model has been chosen for analysis with regard to the geometric discontinuities of piezoelectric layer attachment and NMC's cross section. The force between the tip and the sample surface is modeled using Leonard-Jones potential. Assuming that cantilever is inclined to the sample surface, the effect of nonlinear force on NMC is considered as a shearing force and the concentrated bending moment is regarded at the end. Nonlinear frequency response of NMC is obtained close to the sample surface using the dynamic modeling. It is then become clear that the distance and angle of NMC, the probe length, and the geometric dimensions of piezoelectric layer can affect frequency response bending of the curve.

  3. A low-noise measurement system for scanning thermal microscopy resistive nanoprobes based on a transformer ratio-arm bridge

    Science.gov (United States)

    Świątkowski, Michał; Wojtuś, Arkadiusz; Wielgoszewski, Grzegorz; Rudek, Maciej; Piasecki, Tomasz; Jóźwiak, Grzegorz; Gotszalk, Teodor

    2018-04-01

    Atomic force microscopy (AFM) is a widely used technology for the investigation and characterization of nanomaterials. Its functionality can be easily expanded by applying dedicated extension modules, which can measure the electrical conductivity or temperature of a sample. In this paper, we introduce a transformer ratio-arm bridge setup dedicated to AFM-based thermal imaging. One of the key features of the thermal module is the use of a low-power driving signal that prevents undesirable tip heating during resistance measurement, while the other is the sensor location in a ratio-arm transformer bridge working in the audio frequency range and ensuring galvanic isolation of the tip, enabling contact-mode scanning of electronic circuits. The proposed expansion module is compact and it can be integrated onto the AFM head close to the cantilever. The calibration process and the resolution of 11 mK of the proposed setup are shown.

  4. Cantilever piezoelectric energy harvester with multiple cavities

    International Nuclear Information System (INIS)

    S Srinivasulu Raju; M Umapathy; G Uma

    2015-01-01

    Energy harvesting employing piezoelectric materials in mechanical structures such as cantilever beams, plates, diaphragms, etc, has been an emerging area of research in recent years. The research in this area is also focused on structural tailoring to improve the harvested power from the energy harvesters. Towards this aim, this paper presents a method for improving the harvested power from a cantilever piezoelectric energy harvester by introducing multiple rectangular cavities. A generalized model for a piezoelectric energy harvester with multiple rectangular cavities at a single section and two sections is developed. A method is suggested to optimize the thickness of the cavities and the number of cavities required to generate a higher output voltage for a given cantilever beam structure. The performance of the optimized energy harvesters is evaluated analytically and through experimentation. The simulation and experimental results show that the performance of the energy harvester can be increased with multiple cavities compared to the harvester with a single cavity. (paper)

  5. An experimentally validated bimorph cantilever model for piezoelectric energy harvesting from base excitations

    International Nuclear Information System (INIS)

    Erturk, A; Inman, D J

    2009-01-01

    Piezoelectric transduction has received great attention for vibration-to-electric energy conversion over the last five years. A typical piezoelectric energy harvester is a unimorph or a bimorph cantilever located on a vibrating host structure, to generate electrical energy from base excitations. Several authors have investigated modeling of cantilevered piezoelectric energy harvesters under base excitation. The existing mathematical modeling approaches range from elementary single-degree-of-freedom models to approximate distributed parameter solutions in the sense of Rayleigh–Ritz discretization as well as analytical solution attempts with certain simplifications. Recently, the authors have presented the closed-form analytical solution for a unimorph cantilever under base excitation based on the Euler–Bernoulli beam assumptions. In this paper, the analytical solution is applied to bimorph cantilever configurations with series and parallel connections of piezoceramic layers. The base excitation is assumed to be translation in the transverse direction with a superimposed small rotation. The closed-form steady state response expressions are obtained for harmonic excitations at arbitrary frequencies, which are then reduced to simple but accurate single-mode expressions for modal excitations. The electromechanical frequency response functions (FRFs) that relate the voltage output and vibration response to translational and rotational base accelerations are identified from the multi-mode and single-mode solutions. Experimental validation of the single-mode coupled voltage output and vibration response expressions is presented for a bimorph cantilever with a tip mass. It is observed that the closed-form single-mode FRFs obtained from the analytical solution can successfully predict the coupled system dynamics for a wide range of electrical load resistance. The performance of the bimorph device is analyzed extensively for the short circuit and open circuit resonance

  6. A comparative finite elemental analysis of glass abutment supported and unsupported cantilever fixed partial denture.

    Science.gov (United States)

    Ramakrishaniah, Ravikumar; Al Kheraif, Abdulaziz A; Elsharawy, Mohamed A; Alsaleh, Ayman K; Ismail Mohamed, Karem M; Rehman, Ihtesham Ur

    2015-05-01

    The purpose of this study was to investigate and compare the load distribution and displacement of cantilever prostheses with and without glass abutment by three dimensional finite element analysis. Micro-computed tomography was used to study the relationship between the glass abutment and the ridge. The external surface of the maxilla was scanned, and a simplified finite element model was constructed. The ZX-27 glass abutment and the maxillary first and second premolars were created and modified. The solid model of the three-unit cantilever fixed partial denture was scanned, and the fitting surface was modified with reference to the created abutments using the 3D CAD system. The finite element analysis was completed in ANSYS. The fit and total gap volume between the glass abutment and dental model were determined by Skyscan 1173 high-energy spiral micro-CT scan. The results of the finite element analysis in this study showed that the cantilever prosthesis supported by the glass abutment demonstrated significantly less stress on the terminal abutment and overall deformation of the prosthesis under vertical and oblique load. Micro-computed tomography determined a gap volume of 6.74162 mm(3). By contacting the mucosa, glass abutments transfer some amount of masticatory load to the residual alveolar ridge, thereby preventing damage to the periodontal microstructures of the terminal abutment. The passive contact of the glass abutment with the mucosa not only preserves the health of the mucosa covering the ridge but also permits easy cleaning. It is possible to increase the success rate of cantilever FPDs by supporting the cantilevered pontic with glass abutments. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. Self-heating in piezoresistive cantilevers.

    Science.gov (United States)

    Doll, Joseph C; Corbin, Elise A; King, William P; Pruitt, Beth L

    2011-05-30

    We report experiments and models of self-heating in piezoresistive microcantilevers that show how cantilever measurement resolution depends on the thermal properties of the surrounding fluid. The predicted cantilever temperature rise from a finite difference model is compared with detailed temperature measurements on fabricated devices. Increasing the fluid thermal conductivity allows for lower temperature operation for a given power dissipation, leading to lower force and displacement noise. The force noise in air is 76% greater than in water for the same increase in piezoresistor temperature.

  8. Design & fabrication of cantilever array biosensors

    DEFF Research Database (Denmark)

    Boisen, Anja; Thundat, T

    2009-01-01

    Surface immobilization of functional receptors on microfabricated cantilever arrays offers a new paradigm for the development of biosensors based on nanomechanics. Microcantilever-based systems are capable of real-time, multiplexed detection of unlabeled disease markers in extremely small volumes......, electronic processing, and even local telemetry on a single chip have the potential of satisfying the need for highly sensitive and selective multiple-target detection in very small samples. Here we will review the design and fabrication process of cantilever-based biosensors....

  9. Electronically droplet energy harvesting using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud Al

    2012-01-01

    A report is presented on free falling droplet energy harvesting using piezoelectric cantilevers. The harvester incorporates a multimorph clamped-free cantilever which is composed of five layers of lead zirconate titanate piezoelectric thick films. During the impact, the droplet kinetic energy is transferred into the form of mechanical stress forcing the piezoelectric structure to vibrate. Experimental results show energy of 0.3 μJ per droplet. The scenario of moderate falling drop intensity, i.e. 230 drops per second, yields a total energy of 400 μJ. © 2012 The Institution of Engineering and Technology.

  10. Physics-based signal processing algorithms for micromachined cantilever arrays

    Science.gov (United States)

    Candy, James V; Clague, David S; Lee, Christopher L; Rudd, Robert E; Burnham, Alan K; Tringe, Joseph W

    2013-11-19

    A method of using physics-based signal processing algorithms for micromachined cantilever arrays. The methods utilize deflection of a micromachined cantilever that represents the chemical, biological, or physical element being detected. One embodiment of the method comprises the steps of modeling the deflection of the micromachined cantilever producing a deflection model, sensing the deflection of the micromachined cantilever and producing a signal representing the deflection, and comparing the signal representing the deflection with the deflection model.

  11. 〈c + a〉 Dislocations in deformed Ti–6Al–4V micro-cantilevers

    International Nuclear Information System (INIS)

    Ding, Rengen; Gong, Jicheng; Wilkinson, Angus J.; Jones, Ian P.

    2014-01-01

    Single α–β colony micro-cantilevers with an equilateral triangular cross-section and an apex at the bottom were machined from a polycrystalline commercial Ti–6Al–4V sample using a focused ion beam (FIB). Each cantilever contained several α lamellae separated by thin fillets of β. A nano-indenter was used to perform micro-bending tests (Ding et al., 2012) [1]. 〈c + a〉 Slip systems were selectively activated in the cantilevers by controlling the crystal direction along the micro-cantilever to be [0 0 0 1]. Specimens for transmission electron microscopy were prepared from the deformed micro-cantilevers using a dual-beam FIB. Bright field scanning transmission electron microscopy was used to investigate the processes of slip nucleation, propagation and transmission through the α/β interface. Dislocations initiate first near the bottom of the cantilever and subsequently from the top. Both sets of dislocations move inward toward the neutral axis. Planar pyramidal {101 ¯ 1} slip was observed at the top (tension) but cross-slip was observed at the bottom (compression). All the 〈c + a〉 slip systems are equally stressed, but only a limited number is activated. This is tentatively interpreted in terms of dislocation transmission through the β fillets

  12. Cantilever-Based Microwave Biosensors: Analysis, Designs and Optimizations

    DEFF Research Database (Denmark)

    Jiang, Chenhui; Johansen, Tom Keinicke; Jónasson, Sævar Þór

    2011-01-01

    This paper presents a novel microwave readout scheme for measuring deflection of cantilevers in nanometer range. The cantilever deflection can be sensed by the variation of transmission levels or resonant frequencies of microwave signals. The sensitivity of the cantilever biosensor based on LC...

  13. Polymeric cantilever-based biosensors with integrated readout

    DEFF Research Database (Denmark)

    Johansson, Alicia; Blagoi, Gabriela; Boisen, Anja

    2006-01-01

    The authors present an SU-8 cantilever chip with integrated piezoresistors for detection of surface stress changes due to adsorption of biomolecules on the cantilever surface. Mercaptohexanol is used as a model biomolecule to study molecular interactions with Au-coated SU-8 cantilevers and surfac...

  14. Tip enhancement

    CERN Document Server

    Kawata, Satoshi

    2007-01-01

    This book discusses the recent advances in the area of near-field Raman scattering, mainly focusing on tip-enhanced and surface-enhanced Raman scattering. Some of the key features covered here are the optical structuring and manipulations, single molecule sensitivity, analysis of single-walled carbon nanotubes, and analytic applications in chemistry, biology and material sciences. This book also discusses the plasmonic materials for better enhancement, and optical antennas. Further, near-field microscopy based on second harmonic generation is also discussed. Chapters have been written by some of the leading scientists in this field, who present some of their recent work in this field.·Near-field Raman scattering·Tip-enhanced Raman spectroscopy·Surface-enhanced Raman spectroscopy·Nano-photonics·Nanoanalysis of Physical, chemical and biological materials beyond the diffraction limits·Single molecule detection

  15. Influences of thickness, scanning velocity and relative humidity on the frictional properties of WS2 nanosheets

    Science.gov (United States)

    Feng, Dongdong; Peng, Jinfeng; Liu, Sisi; Zheng, Xuejun; Yan, Xinyang; He, Wenyuan

    2018-01-01

    Distinguishing with the traditional cantilever mechanics method, we propose the extended cantilever mechanics method to calibrate the lateral calibration factor by using the normal spring constant obtained from atomic force microscopy (AFM) but not the Young’s modulus and the width of the cantilever, before the influences of thickness, scanning velocity and humidity on the frictional properties are investigated via friction measurement performed by the lateral force mode (LFM) of AFM. Tungsten disulfide (WS2) nanosheets were prepared through hydrothermal intercalation and exfoliation route, and AFM and Raman microscope were used to investigate the frictional properties, thickness and crystalline structure. The friction force and coefficient decrease monotonically with the increase of the nanosheet’s thickness, and the friction coefficient minimum value is close to 0.012 when the thickness larger than 5 nm. The friction property variation on the nanosheet’s thickness can be explained by the puckering effect of tip-sheet adhesion according thickness dependence of bending stiffness in the frame of continuum mechanics. The friction force is a constant value 1.7 nN when the scanning speed larger than the critical value 3.10 μm s-1, while it logarithmically increases for the scanning speed less than the critical value. It is easy to understand through the energy dissipation model and the thermally activated effect. The friction force and friction coefficient increase with the relative humidity at the range of 30%-60%, and the latter is at the range of 0.010-0.013. Influence of relative humidity is discussed via the increasing area of the water monolayer during the water adsorption process. The research can not only enrich nanotribology theory, but also prompt two dimensions materials for nanomechanical applications.

  16. Near-field scanning optical microscopy based nanostructuring of glass

    International Nuclear Information System (INIS)

    Chimmalgi, A; Hwang, D J; Grigoropoulos, C P

    2007-01-01

    Nanofabrication, at lateral resolutions beyond the capability of conventional optical lithography techniques, is demonstrated here. Femtosecond laser was used in conjunction with Near-field Scanning Optical Microscopes (NSOMs) to nanostructure thin metal films. Also, the possibility of using these nanostructured metal films as masks to effectively transfer the pattern to the underlying substrate by wet etching process is shown. Two different optical nearfiled processing schemes were studied for near-field nanostructuring. In the first scheme, local field enhancement in the near-field of a scanning probe microscope (SPM) probe tip irradiated with femtosecond laser pulses was utilized (apertureless NSOM mode) and as a second approach, femtosecond laser beam was spatially confined by cantilevered NSOM fiber tip (apertured NOSM mode). The minimized heat- and shock-affected areas introduced during ultrafast laser based machining process, allows processing of even high conductivity thin metal films with minimized formation of any interfacial compounds between the metal films and the underlying substrate. Potential applications of this method may be in the fields of nanolithography, nanofluidics, nanoscale chemical and gas sensors, high-density data storage, nano-opto-electronics, as well as biotechnology related applications

  17. Microstructure cantilever beam for current measurement

    Directory of Open Access Journals (Sweden)

    M.T.E. Khan

    2010-01-01

    Full Text Available Most microelectromechanical systems (MEMS sensors are based on the microcantilever technology, which uses a broad range of design materials and structures. The benefit ofMEMStechnology is in developing devices with a lower cost, lower power consumption, higher performance and greater integration. A free-end cantilever beam with a magnetic material mass has been designed using MEMS software tools. The magnetic material was used to improve the sensitivity of the cantilever beam to an externally-applied magnetic field. The cantilever was designed to form a capacitance transducer, which consisted of variable capacitance where electrical and mechanical energies were exchanged. The aim of this paper was to analyse the system design of the microcantilever when subjected to a magnetic field produced by a current-carrying conductor. When the signal, a sinusoidal current with a constant frequency, was applied, the cantilever beam exhibited a vibration motion along the vertical axis when placed closer to the line current. This motion created corresponding capacitance changes and generated a voltage output proportional to the capacitive change in the signal-processing circuitry attached to the microcantilever. The equivalent massspring system theory was used to describe and analyse the effect of the natural frequency of the system vibrations and motion due to the applied magnetic field, in a single-degree of freedom. The main application of this microcantilever is in current measurements to develop a non-contact current sensor mote.

  18. Development of a microfabricated electrochemical-cantilever hybrid platform

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie; Pedersen, Christoffer; Elkjær, Karl

    2011-01-01

    The design and fabrication of a combined electrochemical-cantilever microfluidic system is described. A chip integrating cantilevers with electrodes into a microchannel is presented with the accompanying polymer flow cell. Issues such as electrical and fluid connections are addressed......, electromechanical behavior in ionic solution is investigated, and two uses of the system are demonstrated. First, all cantilevers are functionalized with cysteine, to facilitate detection of Cu2+ ions, then one cantilever is electrochemically cleaned in situ to generate a reference cantilever for differential...

  19. Enhancing output power of a piezoelectric cantilever energy harvester using an oscillator

    International Nuclear Information System (INIS)

    Liu, Haili; Huang, Zhenyu; Xu, Tianzhu; Chen, Dayue

    2012-01-01

    The piezoelectric cantilever with a tip mass (Mass-PC), as a conventional vibration energy harvester, usually works at its fundamental frequency matching ambient excitation. By attaching an oscillator to a piezoelectric cantilever (Osc-PC), a double-mode energy harvester is developed to harvest more power from two matched ambient driving frequencies. Meanwhile, it allows the first operating frequency of the Osc-PC to be adjusted to be very low with only a limited mass attached. A distributed-parameter model of this harvester and the explicit expressions of its operating frequencies are derived to analyze and design the Osc-PC. Numerical investigations reveal that a heaver oscillator placed near the clamped end of the piezoelectric cantilever has better performance at the given exciting frequencies. Following the specified design criteria, an Osc-PC whose operating frequencies match two given exciting frequencies was constructed for the purpose of experimental testing. The results show that, compared to that of a corresponding Mass-PC whose operating frequency matches the lower exciting frequency, the energy harvesting efficiency of the Osc-PC increases by almost four times at the first operating frequency, while the output power at the second operating frequency of the Osc-PC accounts for 68% of that of the Mass-PC. (paper)

  20. Label-free glucose detection using cantilever sensor technology based on gravimetric detection principles.

    Science.gov (United States)

    Hsieh, Shuchen; Hsieh, Shu-Ling; Hsieh, Chiung-Wen; Lin, Po-Chiao; Wu, Chun-Hsin

    2013-01-01

    Efficient maintenance of glucose homeostasis is a major challenge in diabetes therapy, where accurate and reliable glucose level detection is required. Though several methods are currently used, these suffer from impaired response and often unpredictable drift, making them unsuitable for long-term therapeutic practice. In this study, we demonstrate a method that uses a functionalized atomic force microscope (AFM) cantilever as the sensor for reliable glucose detection with sufficient sensitivity and selectivity for clinical use. We first modified the AFM tip with aminopropylsilatrane (APS) and then adsorbed glucose-specific lectin concanavalin A (Con A) onto the surface. The Con A/APS-modified probes were then used to detect glucose by monitoring shifts in the cantilever resonance frequency. To confirm the molecule-specific interaction, AFM topographical images were acquired of identically treated silicon substrates which indicated a specific attachment for glucose-Con A and not for galactose-Con A. These results demonstrate that by monitoring the frequency shift of the AFM cantilever, this sensing system can detect the interaction between Con A and glucose, one of the biomolecule recognition processes, and may assist in the detection and mass quantification of glucose for clinical applications with very high sensitivity.

  1. Calibration of optical cantilever deflection readers

    International Nuclear Information System (INIS)

    Hu Zhiyu; Seeley, Tim; Kossek, Sebastian; Thundat, Thomas

    2004-01-01

    Because of its ultrahigh sensitivity, the optical lever detection method similar to that used in the atomic force microscope (AFM) has been widely employed as a standard technique for measuring microcantilever deflection. Along with the increasing interest in using the microcantilever as a sensing platform, there is also a requirement for a reliable calibration technique. Many researchers have used the concept of optical lever detection to construct microcantilever deflection readout instruments for chemical, physical, and biological detection. However, without an AFM piezo z scanner, it is very difficult to precisely calibrate these instruments. Here, we present a step-by-step method to conveniently calibrate an instrument using commercially available piezoresistive cantilevers. The experimental results closely match the theoretical calculation. Following this procedure, one can easily calibrate any optical cantilever deflection detection system with high reproducibility, precision, and reliability. A detailed discussion of the optical lever readout system design has been addressed in this article

  2. Magnetic elements for switching magnetization magnetic force microscopy tips

    International Nuclear Information System (INIS)

    Cambel, V.; Elias, P.; Gregusova, D.; Martaus, J.; Fedor, J.; Karapetrov, G.; Novosad, V.

    2010-01-01

    Using combination of micromagnetic calculations and magnetic force microscopy (MFM) imaging we find optimal parameters for novel magnetic tips suitable for switching magnetization MFM. Switching magnetization MFM is based on two-pass scanning atomic force microscopy with reversed tip magnetization between the scans. Within the technique the sum of the scanned data with reversed tip magnetization depicts local atomic forces, while their difference maps the local magnetic forces. Here we propose the design and calculate the magnetic properties of tips suitable for this scanning probe technique. We find that for best performance the spin-polarized tips must exhibit low magnetic moment, low switching fields, and single-domain state at remanence. The switching field of such tips is calculated and optimum shape of the Permalloy elements for the tips is found. We show excellent correspondence between calculated and experimental results for Py elements.

  3. Orthodontic Traction of Impacted Canine Using Cantilever

    OpenAIRE

    Nakandakari, Cláudia; Gonçalves, João Roberto; Cassano, Daniel Serra; Raveli, Taísa Boamorte; Bianchi, Jonas; Raveli, Dirceu Barnabé

    2016-01-01

    The impaction of the maxillary canines causes relevant aesthetic and functional problems. The multidisciplinary approach to the proper planning and execution of orthodontic traction of the element in question is essential. Many strategies are cited in the literature; among them is the good biomechanical control in order to avoid possible side effects. The aim of this paper is to present a case report in which a superior canine impacted by palatine was pulled out with the aid of the cantilever...

  4. Cantilever steel post damaged by wind

    Directory of Open Access Journals (Sweden)

    Wei Sha

    2014-10-01

    Full Text Available An analysis for the cause of fracture failure of a cantilever steel sign post damaged by wind has been carried out. An unusual cause of failure has been identified, which is the subject of this paper. Microscopy and microanalysis of the fracture surface showed that the failure was due to pre-existing cracks, from the fabrication of the post. This conclusion was reached after detecting and analysing a galvanised layer on the fracture surfaces.

  5. Dynamic state switching in nonlinear multiferroic cantilevers

    Science.gov (United States)

    Wang, Yi; Onuta, Tiberiu-Dan; Long, Christian J.; Lofland, Samuel E.; Takeuchi, Ichiro

    2013-03-01

    We demonstrate read-write-read-erase cyclical mechanical-memory properties of all-thin-film multiferroic heterostructured Pb(Zr0.52Ti0.48) O3 / Fe0.7Ga0.3 cantilevers when a high enough voltage around the resonant frequency of the device is applied on the Pb(Zr0.52Ti0.48) O3 piezo-film. The device state switching process occurs due to the presence of a hysteresis loop in the piezo-film frequency response, which comes from the nonlinear behavior of the cantilever. The reference frequency at which the strain-mediated Fe0.7Ga0.3 based multiferroic device switches can also be tuned by applying a DC magnetic field bias that contributes to the increase of the cantilever effective stiffness. The switching dynamics is mapped in the phase space of the device measured transfer function characteristic for such high piezo-film voltage excitation, providing additional information on the dynamical stability of the devices.

  6. Optimization of Q-factor of AFM cantilevers using genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Cruz, Angel, E-mail: elapc27@gmail.com [Faculty of Engineering, Universidad Autonoma de Queretaro, Queretaro (Mexico); Dominguez-Gonzalez, Aurelio [Faculty of Engineering, Universidad Autonoma de Queretaro, Queretaro (Mexico); Stiharu, Ion [Department of Mechanical and Industrial Engineering, Concordia University, Montreal (Canada); Osornio-Rios, Roque A. [Faculty of Engineering, Universidad Autonoma de Queretaro, Queretaro (Mexico)

    2012-04-15

    Micro cantilever beams have been intensively used in sensing applications including to scanning profiles and surfaces where there resolution and imaging speed are critical. Force resolution is related to the Q-factor. When the micro-cantilever operates in air with small separation gaps, the Q-factor is even more reduced due to the squeeze-film damping effect. Thus, the optimization of the configuration of an AFM micro-cantilever is presented in this work with the objective of improving its Q-factor. To accomplish this task, we propose the inclusion of holes as breathing chimneys in the initial design to reduce the squeeze-film damping effect. The evaluation of the Q-factor was carried out using finite element model, which is implemented to work together with the squeeze-film damping model. The methodology applied in the optimization process was genetic algorithms, which considers as constraints the maximum allowable stress, fundamental frequency and spring constant with respect to the initial design. The results show that the optimum design, which includes holes with an optimal location, increases the Q-factor almost five times compared to the initial design. -- Highlights: Black-Right-Pointing-Pointer It was optimized the Q-factor of a cantilever, which operates near to the surface in air. Black-Right-Pointing-Pointer It was proposed the inclusion of holes as breathing chimneys in the cantilever's surface. Black-Right-Pointing-Pointer Genetic algorithms and finite element analysis were applied to find the optimum configuration for the Q-factor. Black-Right-Pointing-Pointer Optimum design keeps first frequency and the spring constant very close to the original and has a better force resolution. Black-Right-Pointing-Pointer Final design can be easily manufactured through a mask.

  7. Nanofabrication of magnetic scanned-probe microscope sensors

    International Nuclear Information System (INIS)

    Chong, B.K.

    2001-10-01

    This thesis presents the development of novel magnetic sensor combined with Atomic Force Microscope probe (AFM) using conventional semiconductor processing techniques and Electron Beam Lithography (EBL). The fabrication of these magnetic sensors was performed on a common micromachined silicon substrate using a generic batch fabrication technique. Sub-micron Hall bar for Scanning Hall probe Microscopy (SHPM) and electromagnetic force coil magnet for Scanning Electromagnetic Force Microscopy (eMFM) were designed and constructed at the apex of Silicon attractive mode cantilever probes. The process demonstrates good control over sensor parameters. Results indicated controllability of Hall bar junction sizes (spatial resolution) to below 100nm and Coil diameter sizes to below 500nm with minimum sizes down to 50nm and 270nm respectively. The process has shown its flexibility to accommodate different material systems. The same technology was used to fabricate multiple devices such as double Hall bars on a tip as well as a small electro-magnet coil probe co-defined with the Hall probe to form a magnetic imaging / modification probe. A conventional Non-Contact mode AFM employing heterodyne interferometry and in-house built electronics was modified for SHPM and eMFM. These probes had been scanned over a commercial computer hard disk. These microscopes showed the capability of resolving magnetic bits and topographic information independently and simultaneously. All scanning experiments were carried out under ambient conditions. The experiments required no extra preparation to be done to the specimen before imaging and measurements were carried out under ambient conditions. These probes offer the prospect of direct magnetic field measurement, non- invasiveness, very close proximity, possible local manipulation, better control over the tip- specimen interaction distance and topographic imaging. It is hoped that these magnetic microscope probes will be of great interest and

  8. 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.

  9. Understanding interferometry for micro-cantilever displacement detection

    Directory of Open Access Journals (Sweden)

    Alexander von Schmidsfeld

    2016-06-01

    Full Text Available Interferometric displacement detection in a cantilever-based non-contact atomic force microscope (NC-AFM operated in ultra-high vacuum is demonstrated for the Michelson and Fabry–Pérot modes of operation. Each mode is addressed by appropriately adjusting the distance between the fiber end delivering and collecting light and a highly reflective micro-cantilever, both together forming the interferometric cavity. For a precise measurement of the cantilever displacement, the relative positioning of fiber and cantilever is of critical importance. We describe a systematic approach for accurate alignment as well as the implications of deficient fiber–cantilever configurations. In the Fabry–Pérot regime, the displacement noise spectral density strongly decreases with decreasing distance between the fiber-end and the cantilever, yielding a noise floor of 24 fm/Hz0.5 under optimum conditions.

  10. Towards easy and reliable AFM tip shape determination using blind tip reconstruction

    International Nuclear Information System (INIS)

    Flater, Erin E.; Zacharakis-Jutz, George E.; Dumba, Braulio G.; White, Isaac A.; Clifford, Charles A.

    2014-01-01

    Quantitative determination of the geometry of an atomic force microscope (AFM) probe tip is critical for robust measurements of the nanoscale properties of surfaces, including accurate measurement of sample features and quantification of tribological characteristics. Blind tip reconstruction, which determines tip shape from an AFM image scan without knowledge of tip or sample shape, was established most notably by Villarrubia [J. Res. Natl. Inst. Stand. Tech. 102 (1997)] and has been further developed since that time. Nevertheless, the implementation of blind tip reconstruction for the general user to produce reliable and consistent estimates of tip shape has been hindered due to ambiguity about how to choose the key input parameters, such as tip matrix size and threshold value, which strongly impact the results of the tip reconstruction. These key parameters are investigated here via Villarrubia's blind tip reconstruction algorithms in which we have added the capability for users to systematically vary the key tip reconstruction parameters, evaluate the set of possible tip reconstructions, and determine the optimal tip reconstruction for a given sample. We demonstrate the capabilities of these algorithms through analysis of a set of simulated AFM images and provide practical guidelines for users of the blind tip reconstruction method. We present a reliable method to choose the threshold parameter corresponding to an optimal reconstructed tip shape for a given image. Specifically, we show that the trend in how the reconstructed tip shape varies with threshold number is so regular that the optimal, or Goldilocks, threshold value corresponds with the peak in the derivative of the RMS difference with respect to the zero threshold curve vs. threshold number. - Highlights: • Blind tip reconstruction algorithms have been implemented and augmented to determine the optimal input parameters. • We demonstrate the capabilities of the algorithms using a simulated AFM

  11. Micro‑cantilevers for optical sensing of biogenic amines

    DEFF Research Database (Denmark)

    Wang, Ying; Bravo Costa, Carlos André; Sobolewska, Elżbieta Karolina

    2017-01-01

    molecules in the gas phase. Different functionalization conditions were investigated by immersing gold coated AFM cantilevers in cyclam solutions at different concentrations, for different functionalization times, and for different post-annealing treatments. The optimum morphology for high capture...... micro-cantilever based mass detection. We demonstrate that besides conventional AFM systems a MEMS cantilever in combination with an optical read out is a powerful analytic system which is highly attractive for widespread use in diagnostic applications, with optimized functionalization conditions...

  12. Lorentz force actuation of a heated atomic force microscope cantilever.

    Science.gov (United States)

    Lee, Byeonghee; Prater, Craig B; King, William P

    2012-02-10

    We report Lorentz force-induced actuation of a silicon microcantilever having an integrated resistive heater. Oscillating current through the cantilever interacts with the magnetic field around a NdFeB permanent magnet and induces a Lorentz force that deflects the cantilever. The same current induces cantilever heating. With AC currents as low as 0.2 mA, the cantilever can be oscillated as much as 80 nm at resonance with a DC temperature rise of less than 5 °C. By comparison, the AC temperature variation leads to a thermomechanical oscillation that is about 1000 times smaller than the Lorentz deflection at the cantilever resonance. The cantilever position in the nonuniform magnetic field affects the Lorentz force-induced deflection, with the magnetic field parallel to the cantilever having the largest effect on cantilever actuation. We demonstrate how the cantilever actuation can be used for imaging, and for measuring the local material softening temperature by sensing the contact resonance shift.

  13. An electrochemical-cantilever platform for hybrid sensing applications

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie; Dohn, Søren; Boisen, Anja

    2011-01-01

    This work presents a fully-functional, microfabricated electrochemical-cantilever hybrid platform with flow control. A new cantilever chip format is designed, fabricated, and mounted in a custom polymer flow cell. Issues such as leakage and optical/electrical access are addressed, and combined...... mechanical and electrochemical performance is investigated. Lastly, a cantilever is “defunctionalized” in situ to create a reference cantilever for differential measurements in detection of Cu2+ ions at concentrations of 10 μM and 100 nM....

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

    International Nuclear Information System (INIS)

    Braunsmann, Christoph; Seifert, Jan; Rheinlaender, Johannes; Schäffer, Tilman E.

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-15

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

  16. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji; Kundhikanjana, Worasom; Kelly, Michael A.; Shen, Zhi-Xun

    2011-01-01

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  17. Fabrication of biopolymer cantilevers using nanoimprint lithography

    DEFF Research Database (Denmark)

    Keller, Stephan Sylvest; Feidenhans'l, Nikolaj Agentoft; Fisker-Bødker, Nis

    2011-01-01

    The biodegradable polymer poly(l-lactide) (PLLA) was introduced for the fabrication of micromechanical devices. For this purpose, thin biopolymer films with thickness around 10 μm were spin-coated on silicon substrates. Patterning of microcantilevers is achieved by nanoimprint lithography. A major...... challenge was the high adhesion between PLLA and silicon stamp. Optimized stamp fabrication and the deposition of a 125 nm thick fluorocarbon anti-stiction coating on the PLLA allowed the fabrication of biopolymer cantilevers. Resonance frequency measurements were used to estimate the Young’s modulus...

  18. Cantilever torque magnetometry on coordination compounds

    DEFF Research Database (Denmark)

    Perfetti, Mauro

    2017-01-01

    compounds, such as quantum computation or information storage. This review enlightens that CTM offers a unique combination of accuracy and precision to disentangle noncollinear contributions inside Single Crystals as well as the sensitivity to detect molecular order of thin films. CTM can also detect......Cantilever Torque Magnetometry (CTM) is one of the leading techniques to deeply understand magnetic anisotropy of coordination compounds. The knowledge of magnetic anisotropy is a mandatory requirement before proceeding with any future application related to the magnetic properties of coordination...... quantum phenomena such as magnetization steps and molecular hysteresis curves. Moreover, it can also provide the energy levels splitting and avefunctions composition, especially if coupled with microwave radiation....

  19. Nanoscale microwave microscopy using shielded cantilever probes

    KAUST Repository

    Lai, Keji

    2011-04-21

    Quantitative dielectric and conductivity mapping in the nanoscale is highly desirable for many research disciplines, but difficult to achieve through conventional transport or established microscopy techniques. Taking advantage of the micro-fabrication technology, we have developed cantilever-based near-field microwave probes with shielded structures. Sensitive microwave electronics and finite-element analysis modeling are also utilized for quantitative electrical imaging. The system is fully compatible with atomic force microscope platforms for convenient operation and easy integration of other modes and functions. The microscope is ideal for interdisciplinary research, with demonstrated examples in nano electronics, physics, material science, and biology.

  20. Cantilever surface stress sensors with single-crystalline silicon piezoresistors

    DEFF Research Database (Denmark)

    Rasmussen, Peter Andreas; Hansen, Ole; Boisen, Anja

    2005-01-01

    We present a cantilever with piezoresistive readout optimized for measuring the static deflection due to isotropic surface stress on the surface of the cantilever [Sens. Actuators B 79(2-3), 115 (2001)]. To our knowledge nobody has addressed the difference in physical regimes, and its influence o...

  1. Development of an Electrochemical-Cantilever Hybrid Platform

    DEFF Research Database (Denmark)

    Fischer, Lee MacKenzie

    . For at binde kobber (II) ioner blev rækker af cantilevere funktionaliseret med aminosyre L-cysteine(Cys) og tetrapeptid Cys-Gly-Gly-His (CGGH). Dette funktionelle lag blev fjernet fra en enkelt cantilever, ved selektivt at anvende et voltammetrisk signal til at generere en ren reference cantilever til brug...

  2. SU-8 Cantilever Sensor with Integrated Read-Out

    DEFF Research Database (Denmark)

    Johansson, Alicia Charlotte

    2007-01-01

    Cantilever baserede biosensorer kan bruges til så kaldet label-free detektion af små koncentrationer af molekyler i en opløsning. Når et specifikt molekyle binder til overfladen af en cantilever induceres et overfladestress som resulterer i en udbøjning af cantileveren. Cantileverens udbøjningen ...

  3. Orthodontic Traction of Impacted Canine Using Cantilever

    Directory of Open Access Journals (Sweden)

    Cláudia Nakandakari

    2016-01-01

    Full Text Available The impaction of the maxillary canines causes relevant aesthetic and functional problems. The multidisciplinary approach to the proper planning and execution of orthodontic traction of the element in question is essential. Many strategies are cited in the literature; among them is the good biomechanical control in order to avoid possible side effects. The aim of this paper is to present a case report in which a superior canine impacted by palatine was pulled out with the aid of the cantilever on the Segmented Arch Technique (SAT concept. A 14.7-year-old female patient appeared at clinic complaining about the absence of the upper right permanent canine. The proposed treatment prioritized the traction of the upper right canine without changing the occlusion and aesthetics. For this, it only installed the upper fixed appliance (Roth with slot 0.018, opting for SAT in order to minimize unwanted side effects. The use of cantilever to the traction of the upper right canine has enabled an efficient and predictable outcome, because it is of statically determined mechanics.

  4. Magnetic force driven magnetoelectric effect in bi-cantilever composites

    Science.gov (United States)

    Zhang, Ru; Wu, Gaojian; Zhang, Ning

    2017-12-01

    The magnetic force driven magnetoelectric (ME) effect in bi-cantilever Mn-Zn-Ferrite /PZT composites is presented. Compared with single cantilever, the ME voltage coefficient in bi-cantilever composite is a little lower and the resonance frequency is higher, but the bi-cantilever structure is advantageous for integration. When the magnetic gap is 3 mm, the ME voltage coefficient can achieve 6.2 Vcm-1Oe-1 at resonance under optimum bias field Hm=1030 Oe; when the magnetic gap is 1.5 mm, the ME voltage coefficient can get the value as high as 4.4 Vcm-1Oe-1 under much lower bias field H=340 Oe. The stable ME effect in bi-cantilever composites has important potential application in the design of new type ME device.

  5. Analytical solutions to the free vibration of a double-walled carbon nanotube carrying a bacterium at its tip

    Energy Technology Data Exchange (ETDEWEB)

    Storch, Joel A. [Department of Mechanical Engineering, California State University, Northridge, CA 91330-8348 (United States); Elishakoff, Isaac [Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL 33431-0991 (United States)

    2013-11-07

    We calculate the natural frequencies and mode shapes of a cantilevered double-walled carbon nanotube carrying a rigid body—representative of a bacterium or virus—at the tip of the outer nanotube. By idealizing the nanotubes as Bernoulli-Euler beams, we are able to obtain exact expressions for both the mode shapes and characteristic frequency equation. Separate analyses are performed for the special case of a concentrated tip mass and the more complicated situation where the tip body also exhibits inertia and mass center offset from the beam tip.

  6. Robust energy harvesting from walking vibrations by means of nonlinear cantilever beams

    Science.gov (United States)

    Kluger, Jocelyn M.; Sapsis, Themistoklis P.; Slocum, Alexander H.

    2015-04-01

    In the present work we examine how mechanical nonlinearity can be appropriately utilized to achieve strong robustness of performance in an energy harvesting setting. More specifically, for energy harvesting applications, a great challenge is the uncertain character of the excitation. The combination of this uncertainty with the narrow range of good performance for linear oscillators creates the need for more robust designs that adapt to a wider range of excitation signals. A typical application of this kind is energy harvesting from walking vibrations. Depending on the particular characteristics of the person that walks as well as on the pace of walking, the excitation signal obtains completely different forms. In the present work we study a nonlinear spring mechanism that is composed of a cantilever wrapping around a curved surface as it deflects. While for the free cantilever, the force acting on the free tip depends linearly on the tip displacement, the utilization of a contact surface with the appropriate distribution of curvature leads to essentially nonlinear dependence between the tip displacement and the acting force. The studied nonlinear mechanism has favorable mechanical properties such as low frictional losses, minimal moving parts, and a rugged design that can withstand excessive loads. Through numerical simulations we illustrate that by utilizing this essentially nonlinear element in a 2 degrees-of-freedom (DOF) system, we obtain strongly nonlinear energy transfers between the modes of the system. We illustrate that this nonlinear behavior is associated with strong robustness over three radically different excitation signals that correspond to different walking paces. To validate the strong robustness properties of the 2DOF nonlinear system, we perform a direct parameter optimization for 1DOF and 2DOF linear systems as well as for a class of 1DOF and 2DOF systems with nonlinear springs similar to that of the cubic spring that are physically realized

  7. A method to provide rapid in situ determination of tip radius in dynamic atomic force microscopy

    International Nuclear Information System (INIS)

    Santos, Sergio; Guang Li; Souier, Tewfik; Gadelrab, Karim; Chiesa, Matteo; Thomson, Neil H.

    2012-01-01

    We provide a method to characterize the tip radius of an atomic force microscopy in situ by monitoring the dynamics of the cantilever in ambient conditions. The key concept is that the value of free amplitude for which transitions from the attractive to repulsive force regimes are observed, strongly depends on the curvature of the tip. In practice, the smaller the value of free amplitude required to observe a transition, the sharper the tip. This general behavior is remarkably independent of the properties of the sample and cantilever characteristics and shows the strong dependence of the transitions on the tip radius. The main advantage of this method is rapid in situ characterization. Rapid in situ characterization enables one to continuously monitor the tip size during experiments. Further, we show how to reproducibly shape the tip from a given initial size to any chosen larger size. This approach combined with the in situ tip size monitoring enables quantitative comparison of materials measurements between samples. These methods are set to allow quantitative data acquisition and make direct data comparison readily available in the community.

  8. Forced vibrations of a cantilever beam

    International Nuclear Information System (INIS)

    Repetto, C E; Roatta, A; Welti, R J

    2012-01-01

    The theoretical and experimental solutions for vibrations of a vertical-oriented, prismatic, thin cantilever beam are studied. The beam orientation is ‘downwards’, i.e. the clamped end is above the free end, and it is subjected to a transverse movement at a selected frequency. Both the behaviour of the device driver and the beam's weak-damping resonance response are compared for the case of an elastic beam made from PVC plastic excited over a frequency range from 1 to 30 Hz. The current analysis predicts the presence of ‘pseudo-nodes’ in the normal modes of oscillation. It is important to note that our results were obtained using very simple equipment, present in the teaching laboratory. (paper)

  9. Stabilizing device for control rod tip

    International Nuclear Information System (INIS)

    Verdone, G.F.

    1982-01-01

    A control rod has a spring device on its lower end for eliminating oscillatory contact of the rod against its adjacent guide tube wall. The base of the device is connected to the lower tip of the rod. A plurality of elongated extensions are cantilevered downward from the base. Each extension has a shoulder for contacting the guide tube, and the plurality of shoulders as a group has a transverse dimension that is preset to be larger than the inner diameter of the guide tube such that an interference fit is obtained when the control rod is inserted in the tube. The elongated extensions form an open-ended, substantially hollow member through which most of the liquid coolant flows, and the spaces between adjacent extensions allow the flow to bypass the shoulders without experiencing a significant pressure drop

  10. Bending and Shear Stresses Developed by the Instantaneous Arrest of the Root of a Moving Cantilever Beam

    Science.gov (United States)

    Stowell, Elbridge, Z; Schwartz, Edward B; Houbolt, John C

    1945-01-01

    A theoretical and experimental investigation has been made of the behavior of a cantilever beam in transverse motion when its root is suddenly brought to rest. Equations are given for determining the stresses, the deflections, and the accelerations that arise in the beam as a result of the impact. The theoretical equations, which have been confirmed experimentally, reveal that, at a given percentage of the distance from root to tip, the bending stresses for a particular mode are independent of the length of the beam, whereas the shear stresses vary inversely with the length.

  11. Optimization of sensitivity and noise in piezoresistive cantilevers

    DEFF Research Database (Denmark)

    Yu, Xiaomei; Thaysen, Jacob; Hansen, Ole

    2002-01-01

    In this article, the sensitivity and the noise of piezoresistive cantilevers were systematically investigated with respect to the piezoresistor geometry, the piezoresistive materials, the doping dose, the annealing temperature, and the operating biased voltage. With the noise optimization results......(-6), the biggest gauge factors was 95, and the minimum detectable deflection (MDD) at 6 V and 200 Hz-measurement bandwidth was 0.3 nm for a single-crystal silicon cantilever. Of the two LPCVD silicon piezoresistive cantilevers, amorphous silicon piezoresistors had relatively lower 1/f noise. The MDD for a LPCVD...

  12. Energy harvesting from radio frequency propagation using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud

    2012-02-01

    This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates in the line it sets an alternating current in the actuator electrodes. This flowing current drives the piezoelectric cantilever to mechanical movement, especially when the frequency of the RF signal matches the mechanical resonant frequency of the cantilever. Output voltage signals versus frequency for both mechanical vibrational and RF signal excitations have been measured using different loads.© 2011 Elsevier Ltd. All rights reserved.

  13. Polymer cantilever platform for dielectrophoretic assembly of carbon nanotubes

    DEFF Research Database (Denmark)

    Johansson, Alicia; Calleja, M.; Dimaki, Maria

    2004-01-01

    A polymer cantilever platform for dielectrophoretic assembly of carbon nanotubes has been designed and realized. Multi-walled carbon nanotubes from aqueous solution have been assembled between two metal electrodes that are separated by 2 mu m and embedded in the polymer cantilever. The entire chip......, except for the metallic electrodes and wiring, was fabricated in the photoresist SU-8. SU-8 allows for an inexpensive, flexible and fast fabrication method, and the cantilever platform provides a hydrophobic surface that should be well suited for nanotube assembly. The device can be integrated in a micro...

  14. On the calibration of rectangular atomic force microscope cantilevers modified by particle attachment and lamination

    International Nuclear Information System (INIS)

    Bowen, James; Zhang, Zhibing; Adams, Michael J; Cheneler, David; Ward, Michael C L; Walliman, Dominic; Arkless, Stuart G

    2010-01-01

    A simple but effective method for estimating the spring constant of commercially available atomic force microscope (AFM) cantilevers is presented, based on estimating the cantilever thickness from knowledge of its length, width, resonant frequency and the presence or absence of an added mass, such as a colloid probe at the cantilever apex, or a thin film of deposited material. The spring constant of the cantilever can then be estimated using standard equations for cantilever beams. The results are compared to spring constant calibration measurements performed using reference cantilevers. Additionally, the effect of the deposition of Cr and Ti thin films onto rectangular Si cantilevers is investigated

  15. Tips on Blood Testing

    Science.gov (United States)

    ... Test Pain, Discomfort and Anxiety Tips to Help Children through Their Medical Tests Tips to Help the Elderly through Their Medical Tests Find Us On Social Media: Facebook Twitter Google Plus Footer Menu Home About ...

  16. High-throughput characterization of stresses in thin film materials libraries using Si cantilever array wafers and digital holographic microscopy.

    Science.gov (United States)

    Lai, Y W; Hamann, S; Ehmann, M; Ludwig, A

    2011-06-01

    We report the development of an advanced high-throughput stress characterization method for thin film materials libraries sputter-deposited on micro-machined cantilever arrays consisting of around 1500 cantilevers on 4-inch silicon-on-insulator wafers. A low-cost custom-designed digital holographic microscope (DHM) is employed to simultaneously monitor the thin film thickness, the surface topography and the curvature of each of the cantilevers before and after deposition. The variation in stress state across the thin film materials library is then calculated by Stoney's equation based on the obtained radii of curvature of the cantilevers and film thicknesses. DHM with nanometer-scale out-of-plane resolution allows stress measurements in a wide range, at least from several MPa to several GPa. By using an automatic x-y translation stage, the local stresses within a 4-inch materials library are mapped with high accuracy within 10 min. The speed of measurement is greatly improved compared with the prior laser scanning approach that needs more than an hour of measuring time. A high-throughput stress measurement of an as-deposited Fe-Pd-W materials library was evaluated for demonstration. The fast characterization method is expected to accelerate the development of (functional) thin films, e.g., (magnetic) shape memory materials, whose functionality is greatly stress dependent. © 2011 American Institute of Physics

  17. High-throughput characterization of stresses in thin film materials libraries using Si cantilever array wafers and digital holographic microscopy

    International Nuclear Information System (INIS)

    Lai, Y. W.; Ludwig, A.; Hamann, S.; Ehmann, M.

    2011-01-01

    We report the development of an advanced high-throughput stress characterization method for thin film materials libraries sputter-deposited on micro-machined cantilever arrays consisting of around 1500 cantilevers on 4-inch silicon-on-insulator wafers. A low-cost custom-designed digital holographic microscope (DHM) is employed to simultaneously monitor the thin film thickness, the surface topography and the curvature of each of the cantilevers before and after deposition. The variation in stress state across the thin film materials library is then calculated by Stoney's equation based on the obtained radii of curvature of the cantilevers and film thicknesses. DHM with nanometer-scale out-of-plane resolution allows stress measurements in a wide range, at least from several MPa to several GPa. By using an automatic x-y translation stage, the local stresses within a 4-inch materials library are mapped with high accuracy within 10 min. The speed of measurement is greatly improved compared with the prior laser scanning approach that needs more than an hour of measuring time. A high-throughput stress measurement of an as-deposited Fe-Pd-W materials library was evaluated for demonstration. The fast characterization method is expected to accelerate the development of (functional) thin films, e.g., (magnetic) shape memory materials, whose functionality is greatly stress dependent.

  18. The TIPS Liquidity Premium

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Simon Riddell, Simon

    We introduce an arbitrage-free term structure model of nominal and real yields that accounts for liquidity risk in Treasury inflation-protected securities (TIPS). The novel feature of our model is to identify liquidity risk from individual TIPS prices by accounting for the tendency that TIPS, lik...

  19. Vibration suppression of a rotating flexible cantilever pipe conveying fluid using piezoelectric layers

    Directory of Open Access Journals (Sweden)

    S. Khajehpour

    Full Text Available AbstractIn this study, the governing equations of a rotating cantilever pipe conveying fluid are derived and the longitudinal and lateral induced vibrations are controlled. The pipe considered as an Euler Bernoulli beam with tip mass which piezoelectric layers attached both side of it as sensors and actuators. The follower force due to the fluid discharge causes both conservative and non-conservative work. For mathematical modeling, the Lagrange-Rayleigh-Ritz technique is utilized. An adaptive-robust control scheme is applied to suppress the vibration of the pipe. The adaptive-robust control method is robust against parameter uncertainties and disturbances. Finally, the system is simulated and the effects of varying parameters are studied. The simulation results show the excellent performance of the controller.

  20. Bidirectional frequency tuning of a piezoelectric energy converter based on a cantilever beam

    International Nuclear Information System (INIS)

    Eichhorn, C; Goldschmidtboeing, F; Woias, P

    2009-01-01

    A piezoelectric energy converter is presented, whose resonance frequency can be tuned by applying mechanical stress to its structure. The converter consists of a piezo-polymer cantilever beam with two additional thin arms, which are used to apply an axial preload to the tip of the beam. The compressive or tensile prestress applied through the arms leads to a shift of the beam's resonance frequency. Experiments with this structure indicate a high potential: the resonance frequency of a harvester to which a compressive preload was applied could be altered from 380 Hz to 292 Hz. In another experiment, a harvester with stiffened arms was tuned from 440 Hz to 460 Hz by applying a tensile preload. In combination with automatic control of the applied force, this type of structure could be used to enhance the performance of energy harvesters in vibrating environments with occasional shifts of the vibrational frequency

  1. Tip studies using CFD and comparison with tip loss models

    DEFF Research Database (Denmark)

    Hansen, Martin Otto Laver; Johansen, J.

    2004-01-01

    The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD......The flow past a rotating LM8.2 blade equipped with two different tips are computed using CFD. The different tip flows are analysed and a comparison with two different tip loss models is made. Keywords: tip flow, aerodynamics, CFD...

  2. Integrated MEMS/NEMS Resonant Cantilevers for Ultrasensitive Biological Detection

    Directory of Open Access Journals (Sweden)

    Xinxin Li

    2009-01-01

    Full Text Available The paper reviews the recent researches implemented in Chinese Academy of Sciences, with achievements on integrated resonant microcantilever sensors. In the resonant cantilevers, the self-sensing elements and resonance exciting elements are both top-down integrated with silicon micromachining techniques. Quite a lot of effort is focused on optimization of the resonance mode and sensing structure for improvement of sensitivity. On the other hand, to enable the micro-cantilevers specifically sensitive to bio/chemical molecules, sensing materials are developed and modified on the cantilever surface with a self-assembled monolayer (SAM based bottom-up construction and surface functionalization. To improve the selectivity of the sensors and depress environmental noise, multiple and localized surface modifications are developed. The achieved volume production capability and satisfactory detecting resolution to trace-level biological antigen of alpha-fetoprotein (AFP give the micro-cantilever sensors a great promise for rapid and high-resoluble detection.

  3. Influence of cantilevered sheet pile deflection on adjacent roadways.

    Science.gov (United States)

    2009-06-01

    Cantilevered sheet pile walls are often used adjacent roadways as temporary support during construction. Excess movement of these walls has led to excessive roadway distress causing additional repairs to be necessary. This study assessed the effects ...

  4. An Experimental and Theoretical Investigation of Electrostatically Coupled Cantilever Microbeams

    KAUST Repository

    Ilyas, Saad; Chappanda, Karumbaiah N.; Hafiz, Md Abdullah Al; Ramini, Abdallah; Younis, Mohammad I.

    2016-01-01

    We present an experimental and theoretical investigation of the static and dynamic behavior of electrostatically coupled laterally actuated silicon microbeams. The coupled beam resonators are composed of two almost identical flexible cantilever

  5. Squeeze-film damping characteristics of cantilever microresonators ...

    African Journals Online (AJOL)

    user

    perturbation approach does not apply to cantilever plates because of ...... Direct coupling of electrostatic and structural domain has been achieved using ... forces are computed to obtain the modal squeeze stiffness and damping parameters.

  6. Nonlinear Phenomena in the Single-Mode Dynamics in an AFM Cantilever Beam

    KAUST Repository

    Ruzziconi, Laura

    2016-12-05

    This study deals with the nonlinear dynamics arising in an atomic force microscope cantilever beam. After analyzing the static behavior, a single degree of freedom Galerkin reduced order model is introduced, which describes the overall scenario of the structure response in a neighborhood of the primary resonance. Extensive numerical simulations are performed when both the forcing amplitude and frequency are varied, ranging from low up to elevated excitations. The coexistence of competing attractors with different characteristics is analyzed. Both the non-resonant and the resonant behavior are observed, as well as ranges of inevitable escape. Versatility of behavior is highlighted, which may be attractive in applications. Special attention is devoted to the effects of the tip-sample separation distance, since this aspect is of fundamental importance to understand the operation of an AFM. We explore the metamorphoses of the multistability region when the tip-sample separation distance is varied. To have a complete description of the AFM response, comprehensive behavior charts are introduced to detect the theoretical boundaries of appearance and disappearance of the main attractors. Also, extensive numerical simulations investigate the AFM response when both the forcing amplitude and the tip-sample separation distance are considered as control parameters. The main features are analyzed in detail and the obtained results are interpreted in terms of oscillations of the cantilever-tip ensemble. However, we note that all the aforementioned results represent the limit when disturbances are absent, which never occurs in practice. Here comes the importance of overcoming local investigations and exploring dynamics from a global perspective, by introducing dynamical integrity concepts. To extend the AFM results to the practical case where disturbances exist, we develop a dynamical integrity analysis. After performing a systematic basin of attraction analysis, integrity

  7. Stability enhancement of an atomic force microscope for long-term force measurement including cantilever modification for whole cell deformation

    Science.gov (United States)

    Weafer, P. P.; McGarry, J. P.; van Es, M. H.; Kilpatrick, J. I.; Ronan, W.; Nolan, D. R.; Jarvis, S. P.

    2012-09-01

    Atomic force microscopy (AFM) is widely used in the study of both morphology and mechanical properties of living cells under physiologically relevant conditions. However, quantitative experiments on timescales of minutes to hours are generally limited by thermal drift in the instrument, particularly in the vertical (z) direction. In addition, we demonstrate the necessity to remove all air-liquid interfaces within the system for measurements in liquid environments, which may otherwise result in perturbations in the measured deflection. These effects severely limit the use of AFM as a practical tool for the study of long-term cell behavior, where precise knowledge of the tip-sample distance is a crucial requirement. Here we present a readily implementable, cost effective method of minimizing z-drift and liquid instabilities by utilizing active temperature control combined with a customized fluid cell system. Long-term whole cell mechanical measurements were performed using this stabilized AFM by attaching a large sphere to a cantilever in order to approximate a parallel plate system. An extensive examination of the effects of sphere attachment on AFM data is presented. Profiling of cantilever bending during substrate indentation revealed that the optical lever assumption of free ended cantilevering is inappropriate when sphere constraining occurs, which applies an additional torque to the cantilevers "free" end. Here we present the steps required to accurately determine force-indentation measurements for such a scenario. Combining these readily implementable modifications, we demonstrate the ability to investigate long-term whole cell mechanics by performing strain controlled cyclic deformation of single osteoblasts.

  8. Piezoresistive cantilever force-clamp system

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung-Jin; Petzold, Bryan C.; Pruitt, Beth L. [Department of Mechanical Engineering, Stanford University, Stanford, California 94305 (United States); Goodman, Miriam B. [Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305 (United States)

    2011-04-15

    We present a microelectromechanical device-based tool, namely, a force-clamp system that sets or ''clamps'' the scaled force and can apply designed loading profiles (e.g., constant, sinusoidal) of a desired magnitude. The system implements a piezoresistive cantilever as a force sensor and the built-in capacitive sensor of a piezoelectric actuator as a displacement sensor, such that sample indentation depth can be directly calculated from the force and displacement signals. A programmable real-time controller operating at 100 kHz feedback calculates the driving voltage of the actuator. The system has two distinct modes: a force-clamp mode that controls the force applied to a sample and a displacement-clamp mode that controls the moving distance of the actuator. We demonstrate that the system has a large dynamic range (sub-nN up to tens of {mu}N force and nm up to tens of {mu}m displacement) in both air and water, and excellent dynamic response (fast response time, <2 ms and large bandwidth, 1 Hz up to 1 kHz). In addition, the system has been specifically designed to be integrated with other instruments such as a microscope with patch-clamp electronics. We demonstrate the capabilities of the system by using it to calibrate the stiffness and sensitivity of an electrostatic actuator and to measure the mechanics of a living, freely moving Caenorhabditis elegans nematode.

  9. Measurement of Mechanical Properties of Cantilever Shaped Materials

    Directory of Open Access Journals (Sweden)

    Thomas Thundat

    2008-05-01

    Full Text Available Microcantilevers were first introduced as imaging probes in Atomic Force Microscopy (AFM due to their extremely high sensitivity in measuring surface forces. The versatility of these probes, however, allows the sensing and measurement of a host of mechanical properties of various materials. Sensor parameters such as resonance frequency, quality factor, amplitude of vibration and bending due to a differential stress can all be simultaneously determined for a cantilever. When measuring the mechanical properties of materials, identifying and discerning the most influential parameters responsible for the observed changes in the cantilever response are important. We will, therefore, discuss the effects of various force fields such as those induced by mass loading, residual stress, internal friction of the material, and other changes in the mechanical properties of the microcantilevers. Methods to measure variations in temperature, pressure, or molecular adsorption of water molecules are also discussed. Often these effects occur simultaneously, increasing the number of parameters that need to be concurrently measured to ensure the reliability of the sensors. We therefore systematically investigate the geometric and environmental effects on cantilever measurements including the chemical nature of the underlying interactions. To address the geometric effects we have considered cantilevers with a rectangular or circular cross section. The chemical nature is addressed by using cantilevers fabricated with metals and/or dielectrics. Selective chemical etching, swelling or changes in Young’s modulus of the surface were investigated by means of polymeric and inorganic coatings. Finally to address the effect of the environment in which the cantilever operates, the Knudsen number was determined to characterize the molecule-cantilever collisions. Also bimaterial cantilevers with high thermal sensitivity were used to discern the effect of temperature

  10. AFM tip characterization by using FFT filtered images of step structures

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yongda, E-mail: yanyongda@hit.edu.cn [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Xue, Bo [Key Laboratory of Micro-systems and Micro-structures Manufacturing of Ministry of Education, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China); Hu, Zhenjiang; Zhao, Xuesen [Center For Precision Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150001 (China)

    2016-01-15

    The measurement resolution of an atomic force microscope (AFM) is largely dependent on the radius of the tip. Meanwhile, when using AFM to study nanoscale surface properties, the value of the tip radius is needed in calculations. As such, estimation of the tip radius is important for analyzing results taken using an AFM. In this study, a geometrical model created by scanning a step structure with an AFM tip was developed. The tip was assumed to have a hemispherical cone shape. Profiles simulated by tips with different scanning radii were calculated by fast Fourier transform (FFT). By analyzing the influence of tip radius variation on the spectra of simulated profiles, it was found that low-frequency harmonics were more susceptible, and that the relationship between the tip radius and the low-frequency harmonic amplitude of the step structure varied monotonically. Based on this regularity, we developed a new method to characterize the radius of the hemispherical tip. The tip radii estimated with this approach were comparable to the results obtained using scanning electron microscope imaging and blind reconstruction methods. - Highlights: • The AFM tips with different radii were simulated to scan a nano-step structure. • The spectra of the simulation scans under different radii were analyzed. • The functions of tip radius and harmonic amplitude were used for evaluating tip. • The proposed method has been validated by SEM imaging and blind reconstruction.

  11. 2D MEMS electrostatic cantilever waveguide scanner for potential image display application

    Directory of Open Access Journals (Sweden)

    Gu Kebin

    2015-01-01

    Full Text Available This paper presents the current status of our micro-fabricated SU-8 2D electrostatic cantilever waveguide scanner. The current design utilizes a monolithically integrated electrostatic push-pull actuator. A 4.0 μm SU-8 rib waveguide design allows a relatively large core cross section (4μm in height and 20 μm in width to couple with existing optical fiber and a broad band single mode operation (λ= 0.7μm to 1.3μm with minimal transmission loss (85% to 87% output transmission efficiency with Gaussian beam profile input. A 2D scanning motion has been successfully demonstrated with two fundamental resonances found at 202 and 536 Hz in vertical and horizontal directions. A 130 μm and 19 μm, corresponding displacement and 0.062 and 0.009 rad field of view were observed at a +150V input. Beam divergence from the waveguide was corrected by a focusing GRIN lens and a 5μm beam diameter is observed at the focal plane. The transmission efficiency is low (~10% and cantilever is slightly under tensile residual stress due to inherent imperfection in the process and tooling in fabrication. However, 2D light scanning pattern was successfully demonstrated using 1-D push-pull actuation.

  12. A versatile LabVIEW and field-programmable gate array-based scanning probe microscope for in operando electronic device characterization.

    Science.gov (United States)

    Berger, Andrew J; Page, Michael R; Jacob, Jan; Young, Justin R; Lewis, Jim; Wenzel, Lothar; Bhallamudi, Vidya P; Johnston-Halperin, Ezekiel; Pelekhov, Denis V; Hammel, P Chris

    2014-12-01

    Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In operando characterization of such devices by scanning probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanning probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field-programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically biased graphene field-effect transistor device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.

  13. Efficiency Enhancement of a Cantilever-Based Vibration Energy Harvester

    Directory of Open Access Journals (Sweden)

    Ali E. Kubba

    2013-12-01

    Full Text Available Extracting energy from ambient vibration to power wireless sensor nodes has been an attractive area of research, particularly in the automotive monitoring field. This article reports the design, analysis and testing of a vibration energy harvesting device based on a miniature asymmetric air-spaced cantilever. The developed design offers high power density, and delivers electric power that is sufficient to support most wireless sensor nodes for structural health monitoring (SHM applications. The optimized design underwent three evolutionary steps, starting from a simple cantilever design, going through an air-spaced cantilever, and ending up with an optimized air-spaced geometry with boosted power density level. Finite Element Analysis (FEA was used as an initial tool to compare the three geometries’ stiffness (K, output open-circuit voltage (Vave, and average normal strain in the piezoelectric transducer (εave that directly affect its output voltage. Experimental tests were also carried out in order to examine the energy harvesting level in each of the three designs. The experimental results show how to boost the power output level in a thin air-spaced cantilever beam for energy within the same space envelope. The developed thin air-spaced cantilever (8.37 cm3, has a maximum power output of 2.05 mW (H = 29.29 μJ/cycle.

  14. SU-8 hollow cantilevers for AFM cell adhesion studies

    Science.gov (United States)

    Martinez, Vincent; Behr, Pascal; Drechsler, Ute; Polesel-Maris, Jérôme; Potthoff, Eva; Vörös, Janos; Zambelli, Tomaso

    2016-05-01

    A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m-1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification.

  15. SU-8 hollow cantilevers for AFM cell adhesion studies

    International Nuclear Information System (INIS)

    Martinez, Vincent; Behr, Pascal; Vörös, Janos; Zambelli, Tomaso; Drechsler, Ute; Polesel-Maris, Jérôme; Potthoff, Eva

    2016-01-01

    A novel fabrication method was established to produce flexible, transparent, and robust tipless hollow atomic force microscopy (AFM) cantilevers made entirely from SU-8. Channels of 3 μm thickness and several millimeters length were integrated into 12 μm thick and 40 μm wide cantilevers. Connected to a pressure controller, the devices showed high sealing performance with no leakage up to 6 bars. Changing the cantilever lengths from 100 μm to 500 μm among the same wafer allowed the targeting of various spring constants ranging from 0.5 to 80 N m −1 within a single fabrication run. These hollow polymeric AFM cantilevers were operated in the optical beam deflection configuration. To demonstrate the performance of the device, single-cell force spectroscopy experiments were performed with a single probe detaching in a serial protocol more than 100 Saccharomyces cerevisiae yeast cells from plain glass and glass coated with polydopamine while measuring adhesion forces in the sub-nanoNewton range. SU-8 now offers a new alternative to conventional silicon-based hollow cantilevers with more flexibility in terms of complex geometric design and surface chemistry modification. (paper)

  16. Post-critical behavior of Beck`s column with a tip mass

    DEFF Research Database (Denmark)

    Andersen, S. B.; Thomsen, Jon Juel

    2002-01-01

    This study examines how a tip mass with rotary inertia affects the stability of a follower-loaded cantilevered column. Using nonlinear modeling and perturbation analysis, expressions are set up for determining the stability of the straight column and the amplitude of post-critical flutter...... oscillations. Bifurcation diagrams are given, showing how the vibration amplitude changes with follower load and other parameters. These results agree closely with numerical simulation. It is found that sufficiently large values of tip mass rotary inertia can change the primary bifurcation from supercritical...

  17. Quantitative electromechanical impedance method for nondestructive testing based on a piezoelectric bimorph cantilever

    International Nuclear Information System (INIS)

    Fu, Ji; Tan, Chi; Li, Faxin

    2015-01-01

    The electromechanical impedance (EMI) method, which holds great promise in structural health monitoring (SHM), is usually treated as a qualitative method. In this work, we proposed a quantitative EMI method based on a piezoelectric bimorph cantilever using the sample’s local contact stiffness (LCS) as the identification parameter for nondestructive testing (NDT). Firstly, the equivalent circuit of the contact vibration system was established and the analytical relationship between the cantilever’s contact resonance frequency and the LCS was obtained. As the LCS is sensitive to typical defects such as voids and delamination, the proposed EMI method can then be used for NDT. To verify the equivalent circuit model, two piezoelectric bimorph cantilevers were fabricated and their free resonance frequencies were measured and compared with theoretical predictions. It was found that the stiff cantilever’s EMI can be well predicted by the equivalent circuit model while the soft cantilever’s cannot. Then, both cantilevers were assembled into a homemade NDT system using a three-axis motorized stage for LCS scanning. Testing results on a specimen with a prefabricated defect showed that the defect could be clearly reproduced in the LCS image, indicating the validity of the quantitative EMI method for NDT. It was found that the single-frequency mode of the EMI method can also be used for NDT, which is faster but not quantitative. Finally, several issues relating to the practical application of the NDT method were discussed. The proposed EMI-based NDT method offers a simple and rapid solution for damage evaluation in engineering structures and may also shed some light on EMI-based SHM. (paper)

  18. Thermo-mechanical analysis of FG nanobeam with attached tip mass: an exact solution

    Science.gov (United States)

    Ghadiri, Majid; Jafari, Ali

    2016-12-01

    Present disquisition proposes an analytical solution method for exploring the vibration characteristics of a cantilever functionally graded nanobeam with a concentrated mass exposed to thermal loading for the first time. Thermo-mechanical properties of FGM nanobeam are supposed to change through the thickness direction of beam based on the rule of power-law (P-FGM). The small-scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. Linear temperature rise (LTR) through thickness direction is studied. Existence of centralized mass in the free end of nanobeam influences the mechanical and physical properties. Timoshenko beam theory is employed to derive the nonlocal governing equations and boundary conditions of FGM beam attached with a tip mass under temperature field via Hamilton's principle. An exact solution procedure is exploited to achieve the non-dimensional frequency of FG nanobeam exposed to temperature field with a tip mass. A parametric study is led to assess the efficacy of temperature changes, tip mass, small scale, beam thickness, power-law exponent, slenderness and thermal loading on the natural frequencies of FG cantilever nanobeam with a point mass at the free end. It is concluded that these parameters play remarkable roles on the dynamic behavior of FG nanobeam subjected to LTR with a tip mass. The results for simpler states are confirmed with known data in the literature. Presented numerical results can serve as benchmarks for future thermo-mechanical analyses of FG nanobeam with tip mass.

  19. ADHD: Tips to Try

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español ADHD: Tips to Try KidsHealth / For Teens / ADHD: Tips to Try Print en español TDAH: Consejos que puedes probar ADHD , short for attention deficit hyperactivity disorder , is a ...

  20. Total Telephone Tips.

    Science.gov (United States)

    Corder, Lloyd E.; And Others

    This manual of telephone behavior tips for business and sales professionals offers ways to handle the disgruntled caller and makes suggestions on topics relevant to the telephone. The manual is divided into the following sections and subsections: (1) Common Courtesy (staff tips, answering the telephone, screening calls, transferring calls, taking…

  1. Tip Cells in Angiogenesis

    NARCIS (Netherlands)

    M.G. Dallinga (Marchien); S.E.M. Boas (Sonja); I. Klaassen (Ingeborg); R.M.H. Merks (Roeland); C.J.F. van Noorden; R.O. Schlingemann (Reinier)

    2015-01-01

    htmlabstractIn angiogenesis, the process in which blood vessel sprouts grow out from a pre-existing vascular network, the so-called endothelial tip cells play an essential role. Tip cells are the leading cells of the sprouts; they guide following endothelial cells and sense their environment for

  2. Improved Noninterferometric Test of Collapse Models Using Ultracold Cantilevers

    Science.gov (United States)

    Vinante, A.; Mezzena, R.; Falferi, P.; Carlesso, M.; Bassi, A.

    2017-09-01

    Spontaneous collapse models predict that a weak force noise acts on any mechanical system, as a consequence of the collapse of the wave function. Significant upper limits on the collapse rate have been recently inferred from precision mechanical experiments, such as ultracold cantilevers and the space mission LISA Pathfinder. Here, we report new results from an experiment based on a high-Q cantilever cooled to millikelvin temperatures, which is potentially able to improve the current bounds on the continuous spontaneous localization (CSL) model by 1 order of magnitude. High accuracy measurements of the cantilever thermal fluctuations reveal a nonthermal force noise of unknown origin. This excess noise is compatible with the CSL heating predicted by Adler. Several physical mechanisms able to explain the observed noise have been ruled out.

  3. A new approach for elasto-plastic finite strain analysis of cantilever ...

    Indian Academy of Sciences (India)

    A new approach for elasto-plastic finite strain analysis of cantilever beams subjected to uniform bending moment ... Curvature; deflection curve; cantilever beam; elasto-plastic analysis; tapered beam subjected to tipmoment; ... Sadhana | News.

  4. Fiber-top cantilever: a new generation of micromachined sensors for multipurpose applications

    NARCIS (Netherlands)

    Iannuzzi, D.; Deladi, S.; Schreuders, H.; Slaman, M.; Rector, J.H.; Elwenspoek, Michael Curt

    2006-01-01

    Fiber-top cantilevers are new monolithic devices obtained by carving a cantilever out of the edge of a single-mode optical fiber. Here we report evidences of their potential impact as sensing devices for multipurpose applications.

  5. Evaluation of the safety and efficiency of novel metallic ultrasonic scaler tip on titanium surfaces.

    Science.gov (United States)

    Baek, Seung-Ho; Shon, Won-Jun; Bae, Kwang-Shik; Kum, Kee-Yeon; Lee, Woo-Cheol; Park, Young-Seok

    2012-11-01

    To evaluate the safety and efficiency of novel ultrasonic scaler tips, conventional stainless-steel tips, and plastic tips on titanium surfaces. Mechanical instrumentation was carried out using conventional ultrasonic scalers (EMS, Nyon, Switzerland) with novel metallic implant tip (BS), a plastic-headed tip (ES), a plastic tip (PS) and a conventional stainless-steel tip (CS) on 10 polished commercially pure titanium disks (Grade II) per group. Arithmetic mean roughness (R(a) ) and maximum height roughness (R(y) ) of titanium samples were measured and dissipated power of the scaler tip in the tip-surface junction was estimated to investigate the scaling efficiency. The instrumented surface morphology of samples was viewed with a scanning electron microscope (SEM) and surface profile of the each sample was investigated using contact mode with a commercial atomic force microscope (AFM). There were no significant differences in surface roughness (R(a) and R(y) ) among BS, ES, and PS group. However, CS group showed significant higher surface roughness (R(a) and R(y) ). The efficiency of CS tip is twice as much higher than that of BS tip, the efficiency of BS tip is 20 times higher than that of PS tip, and the efficiency of BS tip is 90 times higher than that of ES tip. Novel metallic copper alloy ultrasonic scaler tips may minimally influence the titanium surface, similar to plastic tip. Therefore, they can be a suitable instrument for implant maintenance therapy. © 2011 John Wiley & Sons A/S.

  6. Pembuatan Cantilever Bridge Anterior Rahang Atas sebagai Koreksi Estetik

    Directory of Open Access Journals (Sweden)

    Yusrina Sumartati

    2012-12-01

    Full Text Available Latar belakang. Kehilangan gigi anterior rahang atas mengakibatkan gangguan fungsi fonetik dan estetik. Gangguan fungsi estetik menyebabkan pasie menjadi rendah diri. Kondisi ini dapat diatasi oleh dokter gigi, salah satunya dengan pembuatan cantilever bridge. Tujuan. Penulisan ini yaitu untuk memberi informasi bahwa pada kasus kehilangan gigi-gigi anterior rahang atas dengan space yang telah menyempit dan malposisi gigi dapat dibuatkan protesa berupa gigi tiruan cekat dengan desain cantilever bridge. Kasus dan perawatan. Laporan kasus ini membahas tentang pasien perempuan umur 39 tahun yang datang ke Rumah Sakit Gigi dan Mulut Prof. Soedomo, dengan keluhan merasa kurang percaya diri karena gigi depan rahang atas hilang sejak 5 tahun yang lalu akibat kecelakaan. Gigi-gigi anterior rahang atas yang masih ada mengalami malposisi akibat pemakaian gigi tiruan sebagian lepasan yang tidak baik. Perawatan yang dilakukan adalah dengan pembuatan cantilever bridge pada gigi 11, 12, 13 dan 21, 22, 23. Kesimpulan. Gangguan fungsi estetik pada gigi anterior rahang atas dapat diatasi dengan pembuatan cantilever bridge.   Background. Maxillary anteriortooth loss resulting in impaired function of phonetic and aesthetic. Impaired function of aesthetic cause patients to become self conscious. This condition can be treated by a dentist, one with a cantilever bridge. Purpose. To inform that in case of missing anterior teeth of the upper jaw with a space that has been narrowed, and malposition of teeth can be made prosthesis denture fixed bridge with a cantilever design. Case and treatment. This case report discusses the 39 years old female patient who came to he Dental Hospital Prof. Soedomo, with complaints of feeling less confident due to the maxillary front teeth missing since 5 years ago due to an accident. Anterior teeth of the upper jaw are still experiencing malposition due to the use of removable partial dentures are not good. The treatment is done is by

  7. Safety Tips: Basketball (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Safety Tips: Basketball KidsHealth / For Parents / Safety Tips: Basketball ... make sure they follow these tips. Why Basketball Safety Is Important Fortunately, very few basketball injuries are ...

  8. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the liver). Portal hypertension can also occur in children, although children are much less likely to require a TIPS. ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  9. Integrated optical readout for miniaturization of cantilever-based sensor system

    DEFF Research Database (Denmark)

    Nordström, Maria; Zauner, Dan; Calleja, Montserrat

    2007-01-01

    The authors present the fabrication and characterization of an integrated optical readout scheme based on single-mode waveguides for cantilever-based sensors. The cantilever bending is read out by monitoring changes in the optical intensity of light transmitted through the cantilever that also acts...

  10. Dynamic of cold-atom tips in anharmonic potentials

    Science.gov (United States)

    Menold, Tobias; Federsel, Peter; Rogulj, Carola; Hölscher, Hendrik; Fortágh, József

    2016-01-01

    Background: Understanding the dynamics of ultracold quantum gases in an anharmonic potential is essential for applications in the new field of cold-atom scanning probe microscopy. Therein, cold atomic ensembles are used as sensitive probe tips to investigate nanostructured surfaces and surface-near potentials, which typically cause anharmonic tip motion. Results: Besides a theoretical description of this anharmonic tip motion, we introduce a novel method for detecting the cold-atom tip dynamics in situ and real time. In agreement with theory, the first measurements show that particle interactions and anharmonic motion have a significant impact on the tip dynamics. Conclusion: Our findings will be crucial for the realization of high-sensitivity force spectroscopy with cold-atom tips and could possibly allow for the development of advanced spectroscopic techniques such as Q-control. PMID:28144505

  11. Lightning Safety Tips and Resources

    Science.gov (United States)

    ... Services Careers Contact Us Glossary Safety National Program Lightning Safety Tips and Resources Weather.gov > Safety > Lightning Safety Tips and Resources Lightning Resources Lightning strikes ...

  12. Tip-enhanced Raman mapping with top-illumination AFM.

    Science.gov (United States)

    Chan, K L Andrew; Kazarian, Sergei G

    2011-04-29

    Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

  13. Tip-enhanced Raman mapping with top-illumination AFM

    Energy Technology Data Exchange (ETDEWEB)

    Chan, K L Andrew; Kazarian, Sergei G, E-mail: s.kazarian@imperial.ac.uk [Department of Chemical Engineering, Imperial College London, SW7 2AZ (United Kingdom)

    2011-04-29

    Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of {approx} 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

  14. Tip-enhanced Raman mapping with top-illumination AFM

    International Nuclear Information System (INIS)

    Chan, K L Andrew; Kazarian, Sergei G

    2011-01-01

    Tip-enhanced Raman mapping is a powerful, emerging technique that offers rich chemical information and high spatial resolution. Currently, most of the successes in tip-enhanced Raman scattering (TERS) measurements are based on the inverted configuration where tips and laser are approaching the sample from opposite sides. This results in the limitation of measurement for transparent samples only. Several approaches have been developed to obtain tip-enhanced Raman mapping in reflection mode, many of which involve certain customisations of the system. We have demonstrated in this work that it is also possible to obtain TERS nano-images using an upright microscope (top-illumination) with a gold-coated Si atomic force microscope (AFM) cantilever without significant modification to the existing integrated AFM/Raman system. A TERS image of a single-walled carbon nanotube has been achieved with a spatial resolution of ∼ 20-50 nm, demonstrating the potential of this technique for studying non-transparent nanoscale materials.

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

    Science.gov (United States)

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

    2015-05-01

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

  16. Chemically etched fiber tips for near-field optical microscopy: a process for smoother tips.

    Science.gov (United States)

    Lambelet, P; Sayah, A; Pfeffer, M; Philipona, C; Marquis-Weible, F

    1998-11-01

    An improved method for producing fiber tips for scanning near-field optical microscopy is presented. The improvement consists of chemically etching quartz optical fibers through their acrylate jacket. This new method is compared with the previous one in which bare fibers were etched. With the new process the meniscus formed by the acid along the fiber does not move during etching, leading to a much smoother surface of the tip cone. Subsequent metallization is thus improved, resulting in better coverage of the tip with an aluminum opaque layer. Our results show that leakage can be avoided along the cone, and light transmission through the tip is spatially limited to an optical aperture of a 100-nm dimension.

  17. Low Vision Tips

    Science.gov (United States)

    ... this page: https://medlineplus.gov/lowvision.html MedlinePlus: Low Vision Tips We are sorry. MedlinePlus no longer maintains the For Low Vision Users page. You will still find health resources ...

  18. Diabetes: Dental Tips

    Science.gov (United States)

    Diabetes: Dental Tips For more copies contact: National Institute of Dental and Craniofacial Research National Oral Health Information Clearinghouse ... damage the gum and bone that hold your teeth in place and may lead to painful chewing ...

  19. Incontinence Treatment: Dietary Tips

    Science.gov (United States)

    ... helpful, please consider supporting IFFGD with a small tax-deductible donation. Lifestyle Changes Dietary Tips Medication Bowel ... arises requiring an expert’s care. © Copyright 1998-2018 International Foundation for Functional Gastrointestinal Disorders, Inc. (IFFGD). All ...

  20. Piezoresistive Cantilever Performance-Part I: Analytical Model for Sensitivity.

    Science.gov (United States)

    Park, Sung-Jin; Doll, Joseph C; Pruitt, Beth L

    2010-02-01

    An accurate analytical model for the change in resistance of a piezoresistor is necessary for the design of silicon piezoresistive transducers. Ion implantation requires a high-temperature oxidation or annealing process to activate the dopant atoms, and this treatment results in a distorted dopant profile due to diffusion. Existing analytical models do not account for the concentration dependence of piezoresistance and are not accurate for nonuniform dopant profiles. We extend previous analytical work by introducing two nondimensional factors, namely, the efficiency and geometry factors. A practical benefit of this efficiency factor is that it separates the process parameters from the design parameters; thus, designers may address requirements for cantilever geometry and fabrication process independently. To facilitate the design process, we provide a lookup table for the efficiency factor over an extensive range of process conditions. The model was validated by comparing simulation results with the experimentally determined sensitivities of piezoresistive cantilevers. We performed 9200 TSUPREM4 simulations and fabricated 50 devices from six unique process flows; we systematically explored the design space relating process parameters and cantilever sensitivity. Our treatment focuses on piezoresistive cantilevers, but the analytical sensitivity model is extensible to other piezoresistive transducers such as membrane pressure sensors.

  1. Piezoresistive Cantilever Performance—Part I: Analytical Model for Sensitivity

    Science.gov (United States)

    Park, Sung-Jin; Doll, Joseph C.; Pruitt, Beth L.

    2010-01-01

    An accurate analytical model for the change in resistance of a piezoresistor is necessary for the design of silicon piezoresistive transducers. Ion implantation requires a high-temperature oxidation or annealing process to activate the dopant atoms, and this treatment results in a distorted dopant profile due to diffusion. Existing analytical models do not account for the concentration dependence of piezoresistance and are not accurate for nonuniform dopant profiles. We extend previous analytical work by introducing two nondimensional factors, namely, the efficiency and geometry factors. A practical benefit of this efficiency factor is that it separates the process parameters from the design parameters; thus, designers may address requirements for cantilever geometry and fabrication process independently. To facilitate the design process, we provide a lookup table for the efficiency factor over an extensive range of process conditions. The model was validated by comparing simulation results with the experimentally determined sensitivities of piezoresistive cantilevers. We performed 9200 TSUPREM4 simulations and fabricated 50 devices from six unique process flows; we systematically explored the design space relating process parameters and cantilever sensitivity. Our treatment focuses on piezoresistive cantilevers, but the analytical sensitivity model is extensible to other piezoresistive transducers such as membrane pressure sensors. PMID:20336183

  2. An Astigmatic Detection System for Polymeric Cantilever-based Sensors

    DEFF Research Database (Denmark)

    Hwu, En-Te; Liao, Hsien-Shun; Bosco, Filippo

    2012-01-01

    fluctuation measurements on cantilever beams with a subnanometer resolution. Furthermore, an external excitation can intensify the resonance amplitude, enhancing the signal- to-noise ratio. The full width at half maximum (FWHM) of the laser spot is 568 nm, which facilitates read-out on potentially...

  3. Energy harvesting from radio frequency propagation using piezoelectric cantilevers

    KAUST Repository

    Al Ahmad, Mahmoud; Alshareef, Husam N.

    2012-01-01

    This work reports an induced strain in a piezoelectric cantilever due to radio frequency signal propagation. The piezoelectric actuator is coupled to radio frequency (RF) line through a gap of 0.25 mm. When a voltage signal of 10 Vpp propagates

  4. Global consequences of a local Casimir force : Adhered cantilever

    NARCIS (Netherlands)

    Svetovoy, V. B.; Melenev, A. E.; Lokhanin, M. V.; Palasantzas, G.

    2017-01-01

    Although stiction is a cumbersome problem for microsystems, it stimulates investigations of surface adhesion. In fact, the shape of an adhered cantilever carries information of the adhesion energy that locks one end to the substrate. We demonstrate here that the system is also sensitive to the

  5. Strategy Guideline: Quality Management in Existing Homes - Cantilever Floor Example

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Sikora, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Wiehagen, J. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States); Wood, A. [NAHB Research Center Industry Partnership, Upper Marlboro, MD (United States)

    2011-12-01

    This guideline is designed to highlight the QA process that can be applied to any residential building retrofit activity. The cantilevered floor retrofit detailed in this guideline is included only to provide an actual retrofit example to better illustrate the QA activities being presented.

  6. AFM cantilever with in situ renewable mercury microelectrode

    NARCIS (Netherlands)

    Schön, Peter Manfred; Geerlings, J.; Tas, Niels Roelof; Sarajlic, Edin

    2013-01-01

    We report here first results obtained on a novel, in situ renewable mercury microelectrode integrated into an atomic force microscopy (AFM) cantilever. Our approach is based on a fountain pen probe with appropriate dimensions enabling reversible filling with(nonwetting) mercury under changing the

  7. Aluminum nano-cantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

  8. Optimised cantilever biosensor with piezoresistive read-out

    DEFF Research Database (Denmark)

    Rasmussen, Peter; Thaysen, J.; Hansen, Ole

    2003-01-01

    We present a cantilever-based biochemical sensor with piezoresistive read-out which has been optimised for measuring surface stress. The resistors and the electrical wiring on the chip are encapsulated in low-pressure chemical vapor deposition (LPCVD) silicon nitride, so that the chip is well sui...

  9. 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

  10. Sobol method application in dimensional sensitivity analyses of different AFM cantilevers for biological particles

    Science.gov (United States)

    Korayem, M. H.; Taheri, M.; Ghahnaviyeh, S. D.

    2015-08-01

    Due to the more delicate nature of biological micro/nanoparticles, it is necessary to compute the critical force of manipulation. The modeling and simulation of reactions and nanomanipulator dynamics in a precise manipulation process require an exact modeling of cantilevers stiffness, especially the stiffness of dagger cantilevers because the previous model is not useful for this investigation. The stiffness values for V-shaped cantilevers can be obtained through several methods. One of them is the PBA method. In another approach, the cantilever is divided into two sections: a triangular head section and two slanted rectangular beams. Then, deformations along different directions are computed and used to obtain the stiffness values in different directions. The stiffness formulations of dagger cantilever are needed for this sensitivity analyses so the formulations have been driven first and then sensitivity analyses has been started. In examining the stiffness of the dagger-shaped cantilever, the micro-beam has been divided into two triangular and rectangular sections and by computing the displacements along different directions and using the existing relations, the stiffness values for dagger cantilever have been obtained. In this paper, after investigating the stiffness of common types of cantilevers, Sobol sensitivity analyses of the effects of various geometric parameters on the stiffness of these types of cantilevers have been carried out. Also, the effects of different cantilevers on the dynamic behavior of nanoparticles have been studied and the dagger-shaped cantilever has been deemed more suitable for the manipulation of biological particles.

  11. Drift study of SU8 cantilevers in liquid and gaseous environments.

    Science.gov (United States)

    Tenje, Maria; Keller, Stephan; Dohn, Søren; Davis, Zachary J; Boisen, Anja

    2010-05-01

    We present a study of the drift, in terms of cantilever deflections without probe/target interactions, of polymeric SU8 cantilevers. The drift is measured in PBS buffer (pH 7.4) and under vacuum (1mbar) conditions. We see that the cantilevers display a large drift in both environments. We believe this is because the polymer matrix absorbs liquid in one situation whereas it is being degassed in the other. An inhomogeneous expansion/contraction of the cantilever is seen because one surface of the cantilever may still have remains of the release layer from the fabrication. To further study the effect, we coat the cantilevers with a hydrophobic coating, perfluorodecyltrichlorosilane (FDTS). Fully encapsulating the SU8 cantilever greatly reduces the drift in liquid whereas a less significant change is seen in vacuum.

  12. Drift study of SU8 cantilevers in liquid and gaseous environments

    DEFF Research Database (Denmark)

    Tenje, Maria; Keller, Stephan Sylvest; Dohn, Søren

    2010-01-01

    We present a study of the drift, in terms of cantilever deflections without probe/target interactions, of polymeric SU8 cantilevers. The drift is measured in PBS buffer (pH 7.4) and under vacuum (1 mbar) conditions. We see that the cantilevers display a large drift in both environments. We believe...... coat the cantilevers with a hydrophobic coating, perfluorodecyltrichlorosilane (FDTS). Fully encapsulating the SU8 cantilever greatly reduces the drift in liquid whereas a less significant change is seen in vacuum....... this is because the polymer matrix absorbs liquid in one situation whereas it is being degassed in the other. An inhomogeneous expansion/contraction of the cantilever is seen because one surface of the cantilever may still have remains of the release layer from the fabrication. To further study the effect, we...

  13. Out-of-plane buckled cantilever microstructures with adjustable angular positions using thermal bimorph actuation for transducer applications

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2015-10-27

    The integration of thermal bimorph actuators and buckled cantilever structures to form an out-of-plane plate with adjustable angular positions is reported. This structure could be used as a platform to build other transducers such as optical micromirrors, scanning antennas, switches or low-frequency oscillators. The electromechanical characterisation has shown that these structures can adjust their angular position by 6° when they are operated using a DC source. The thermal characterisation performed by an infrared camera showed that the heat-affected zone reaches a maximum temperature of 125°C while the rest of the structure remains unaffected by the generated heat.

  14. Nano-DTA and nano-DSC with cantilever-type calorimeter

    International Nuclear Information System (INIS)

    Nakabeppu, Osamu; Deno, Kohei

    2016-01-01

    Highlights: • Nanocalorimetry with original cantilever type calorimeters. • The calorimeters showed the enthalpy resolution of 200 nJ level. • Nano-DTA of a binary alloy captured a probabilistic peak after solidification. • Power compensation DSC of a microgram level sample was demonstrated. • The DSC and DTA behavior were explained with a lumped model. - Abstract: Differential thermal analysis (DTA) and differential scanning calorimetry (DSC) of the minute samples in the range of microgram to nanogram were studied using original cantilever-type calorimeters. The micro-fabricated calorimeter with a heater and thermal sensors was able to perform a fast temperature scan at above 1000 K/s and a high-resolution heat measurement. The DTA of minuscule metal samples demonstrated some advances such as the thermal analysis of a 20 ng level indium and observation of a strange phase transition of a binary alloy. The power compensation type DSC using a thermal feedback system was also performed. Thermal information of a microgram level sample was observed as splitting into the DSC and DTA signals because of a mismatch between the sample and the calorimeter. Although there remains some room for improvement in terms of the heat flow detection, the behavior of the compensation system in the DSC was theoretically understood through a lumped model. Those experiments also produced some findings, such as a fin effect with sample loading, a measurable weight range, a calibration of the calorimeter and a product design concept. The development of the nano-DTA and nano-DSC will enable breakthroughs for the fast calorimetry of the microscopic size samples.

  15. Magnet pole tips

    Science.gov (United States)

    Thorn, Craig E.; Chasman, Chellis; Baltz, Anthony J.

    1984-04-24

    An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.

  16. On developing an optimal design procedure for a bimorph piezoelectric cantilever energy harvester under a predefined volume

    Science.gov (United States)

    Aboulfotoh, Noha; Twiefel, Jens

    2018-06-01

    A typical vibration harvester is tuned to operate at resonance in order to maximize the power output. There are many design parameter sets for tuning the harvester to a specific frequency, even for simple geometries. This work studies the impact of the geometrical parameters on the harvested power while keeping the resonance frequency constant in order to find the combination of the parameters that optimizes the power under a predefined volume. A bimorph piezoelectric cantilever is considered for the study. It consists of two piezoelectric layers and a middle non-piezoelectric layer and holds a tip mass. A theoretical model was derived to obtain the system parameters and the power as functions of the design parameters. Formulas for the optimal load resistance that provide maximum power capability at resonance and anti-resonance frequency were derived. The influence of the width on the power is studied, considering a constant mass ratio (between the tip mass and the mass of the beam). This keeps the resonance frequency constant while changing the width. The influence of the ratio between the thickness of the middle layer and that of the piezoelectric layer is also studied. It is assumed that the total thickness of the cantilever is constant and the middle layer has the same mechanical properties (elasticity and density) as the piezoelectric layer. This keeps the resonance frequency constant while changing the ratio between the thicknesses. Finally, the influence of increasing the free length as well as of increasing the mass ratio on the power is investigated. This is done by first, increasing each of them individually and secondly, by increasing each of them simultaneously while increasing the total thickness under the condition of maintaining a constant resonance frequency. Based on the analysis of these influences, recommendations as to how to maximize the geometrical parameters within the available volume and mass are presented.

  17. Improved flare tip design

    Energy Technology Data Exchange (ETDEWEB)

    Gogolek, P. [Natural Resources Canada, Ottawa, ON (Canada). CANMET Energy Technology Centre

    2004-07-01

    This paper discusses the testing procedures and development of an improved flare tip design. Design objectives included performance equal to or better than utility flares at low wind speed; conversion efficiency; fuel slip; smoking; significant improvement at high wind speed; and no increase in trace emissions. A description of the testing facility of the flare tip was provided, with reference to the fact that the facility allowed for realistic near full scale gas flares in a single-pass flare test facility. Other details of the facility included: an adjustable ceiling; high capacity variable speed fan; sampling ports along working section in stack; windows along working section; and air cooled walls, floor, and ceiling. The fuels used in the flare tip included natural gas, propane, gasoline and inert gases. Details of wind speed, appurtenances and turbulence generating grids were presented, with reference to continuous gas emission measurements. A list of design constraints was provided. Flare performance included wind speed, turbulence and fuel composition. A chart of conversion inefficiencies with a correlation of wind speed and turbulence, fuel flow and pipe size was also presented. Several new tip designs were fabricated for testing, with screening tests for comparison to basic pipe and ranking designs. Significant improvements were found in one of the new designs, including results with 30 per cent propane in fuel. Emissions reduction from 10 to 35 per cent were noted. It was concluded that future work should focus on evaluating improved tip for stability at low wind speeds. Fuel slips are the primary source of emissions, and it was recommended that further research is necessary to improve existing flare tips. tabs, figs.

  18. Productivity tips for developers

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    I like to read about productivity tools and techniques, but the problem is - most of them are completely overrated, the tips are not that useful or they are too difficult to implement. But, sometimes I can find some stuff that really makes me think "damn, how could I live without this before?!". Today, I would like to share some of them and hopefully hear about the tips and tricks that you use. Maybe we can find a way to share them somehow (github repo/forum)?

  19. Influence of Poisson's ratio variation on lateral spring constant of atomic force microscopy cantilevers

    International Nuclear Information System (INIS)

    Yeh, M.-K.; Tai, N.-Ha; Chen, B.-Y.

    2008-01-01

    Atomic force microscopy (AFM) can be used to measure the surface morphologies and the mechanical properties of nanostructures. The force acting on the AFM cantilever can be obtained by multiplying the spring constant of AFM cantilever and the corresponding deformation. To improve the accuracy of force experiments, the spring constant of AFM cantilever must be calibrated carefully. Many methods, such as theoretical equations, the finite element method, and the use of reference cantilever, were reported to obtain the spring constant of AFM cantilevers. For the cantilever made of single crystal, the Poisson's ratio varies with different cantilever-crystal angles. In this paper, the influences of Poisson's ratio variation on the lateral spring constant and axial spring constant of rectangular and V-shaped AFM cantilevers, with different tilt angles and normal forces, were investigated by the finite element analysis. When the cantilever's tilt angle is 20 deg. and the Poisson's ratio varies from 0.02 to 0.4, the finite element results show that the lateral spring constants decrease 11.75% for the rectangular cantilever with 1 μN landing force and decrease 18.60% for the V-shaped cantilever with 50 nN landing force, respectively. The influence of Poisson's ratio variation on axial spring constant is less than 3% for both rectangular and V-shaped cantilevers. As the tilt angle increases, the axial spring constants for rectangular and V-shaped cantilevers decrease substantially. The results obtained can be used to improve the accuracy of the lateral force measurement when using atomic force microscopy

  20. Intrinsically aligned chemo-mechanical functionalization of twin cantilever structures

    International Nuclear Information System (INIS)

    Toffoli, V; Esch, F; Melli, M; Pozzato, A; Tormen, M; Lazzarino, M; Cataruzza, F; Carrato, S; Scoles, G

    2008-01-01

    Mechanical oscillators became a main focus of research in recent years for potential applications in biomolecule detectors. We recently demonstrated the feasibility of a scheme based on twin cantilevers with a sensitivity down to the single molecule. This approach is extremely promising under the condition that the two terminals of the device can be functionalized with high selectivity and nanometric accuracy by linker molecules. Here we demonstrate a chemo-mechanical method to achieve the intrinsically aligned functionalization of two silicon surfaces, which can be separated by a gap controllable with nanometric precision. The chemical binding of the target molecules in the selected position is obtained through a cycloaddition reaction which exploits the reactivity of the freshly cleaved surfaces that form when the cantilever gap is created. The general validity of this approach is shown by the use in different chemical environments of two compounds with different reactive functional groups.

  1. Direct and quantitative broadband absorptance spectroscopy with multilayer cantilever probes

    Science.gov (United States)

    Hsu, Wei-Chun; Tong, Jonathan Kien-Kwok; Liao, Bolin; Chen, Gang

    2015-04-21

    A system for measuring the absorption spectrum of a sample is provided that includes a broadband light source that produces broadband light defined within a range of an absorptance spectrum. An interferometer modulates the intensity of the broadband light source for a range of modulation frequencies. A bi-layer cantilever probe arm is thermally connected to a sample arm having at most two layers of materials. The broadband light modulated by the interferometer is directed towards the sample and absorbed by the sample and converted into heat, which causes a temperature rise and bending of the bi-layer cantilever probe arm. A detector mechanism measures and records the deflection of the probe arm so as to obtain the absorptance spectrum of the sample.

  2. First application of multilayer graphene cantilever for laser photoacoustic detection

    Czech Academy of Sciences Publication Activity Database

    Suchánek, Jan; Dostál, Michal; Vlasáková, T.; Janda, Pavel; Klusáčková, Monika; Kubát, Pavel; Nevrlý, V.; Bitala, P.; Civiš, Svatopluk; Zelinger, Zdeněk

    2017-01-01

    Roč. 101, APR 2017 (2017), s. 9-14 ISSN 0263-2241 R&D Projects: GA ČR(CZ) GA14-14696S; GA MŠk(CZ) LD14022 Grant - others:COST(XE) TD1105 Institutional support: RVO:61388955 Keywords : Cantilever * Multilayer graphene * Photoacoustic detection * Methanol detection Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.359, year: 2016

  3. Simulation Study on Material Property of Cantilever Piezoelectric Vibration Generator

    Directory of Open Access Journals (Sweden)

    Yan Zhen

    2014-06-01

    Full Text Available For increasing generating capacity of cantilever piezoelectric vibration generator with limited volume, relation between output voltage, inherent frequency and material parameter of unimorph, bimorph in series type and bimorph in parallel type piezoelectric vibration generator is analyzed respectively by mechanical model and finite element modeling. The results indicate PZT-4, PZT- 5A and PZT-5H piezoelectric materials and stainless steel, nickel alloy substrate material should be firstly chosen.

  4. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    OpenAIRE

    Toffoli, Valeria; Carrato, Sergio; Lee, Dongkyu; Jeon, Sangmin; Lazzarino, Marco

    2013-01-01

    The design and characteristics of a micro-system for thermogravimetric analysis (TGA) in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using mill...

  5. Unstable oscillation of tubular cantilevered beams conveying a compressible fluid

    International Nuclear Information System (INIS)

    Johnson, R.O.; Stoneking, J.E.; Carley, T.G.

    1986-01-01

    This paper is concerned with establishing the conditions of stability of a cantilevered tube conveying a compressible fluid. Solutions to Niordson's eigenvalue problem associated with the equations of motion are computed using Muller's method. The effects on critical velocity of compressibility which are accommodated by specifying the tube aspect ratio and fluid sonic velocity are parametrically studied. Aspect ratio is found to have a more pronounced effect on critical velocity than sonic velocity over the parameter range that was considered. (orig.)

  6. Characterizing Vibrating Cantilevers for Liquid Viscosity and Density Sensing

    Directory of Open Access Journals (Sweden)

    Bernhard Jakoby

    2008-10-01

    Full Text Available Miniaturized liquid sensors are essential devices in online process or condition monitoring. In case of viscosity and density sensing, microacoustic sensors such as quartz crystal resonators or SAW devices have proved particularly useful. However, these devices basically measure a thin-film viscosity, which is often not comparable to the macroscopic parameters probed by conventional viscometers. Miniaturized cantilever-based devices are interesting alternatives for such applications, but here the interaction between the liquid and the oscillating beam is more involved. In our contribution, we describe a measurement setup, which allows the investigation of this interaction for different beam cross-sections. We present an analytical model based on an approximation of the immersed cantilever as an oscillating sphere comprising the effective mass and the intrinsic damping of the cantilever and additional mass and damping due to the liquid loading. The model parameters are obtained from measurements with well-known sample liquids by a curve fitting procedure. Finally, we present the measurement of viscosity and density of an unknown sample liquid, demonstrating the feasibility of the model.

  7. Dynamic modelling and experimental study of cantilever beam with clearance

    International Nuclear Information System (INIS)

    Li, B; Jin, W; Han, L; He, Z

    2012-01-01

    Clearances occur in almost all mechanical systems, typically such as the clearance between slide plate of gun barrel and guide. Therefore, to study the clearances of mechanisms can be very important to increase the working performance and lifetime of mechanisms. In this paper, rigid dynamic modelling of cantilever with clearance was done according to the subject investigated. In the rigid dynamic modelling, clearance is equivalent to the spring-dashpot model, the impact of beam and boundary face was also taken into consideration. In ADAMS software, the dynamic simulation was carried out according to the model above. The software simulated the movement of cantilever with clearance under external excitation. Research found: When the clearance is larger, the force of impact will become larger. In order to study how the stiffness of the cantilever's supporting part influences natural frequency of the system, A Euler beam which is restricted by a draught spring and a torsion spring at its end was raised. Through numerical calculation, the relationship between natural frequency and stiffness was found. When the value of the stiffness is close to the limit value, the corresponding boundary condition is illustrated. An ADAMS experiment was carried out to check the theory and the simulation.

  8. Dynamic modelling and experimental study of cantilever beam with clearance

    Science.gov (United States)

    Li, B.; Jin, W.; Han, L.; He, Z.

    2012-05-01

    Clearances occur in almost all mechanical systems, typically such as the clearance between slide plate of gun barrel and guide. Therefore, to study the clearances of mechanisms can be very important to increase the working performance and lifetime of mechanisms. In this paper, rigid dynamic modelling of cantilever with clearance was done according to the subject investigated. In the rigid dynamic modelling, clearance is equivalent to the spring-dashpot model, the impact of beam and boundary face was also taken into consideration. In ADAMS software, the dynamic simulation was carried out according to the model above. The software simulated the movement of cantilever with clearance under external excitation. Research found: When the clearance is larger, the force of impact will become larger. In order to study how the stiffness of the cantilever's supporting part influences natural frequency of the system, A Euler beam which is restricted by a draught spring and a torsion spring at its end was raised. Through numerical calculation, the relationship between natural frequency and stiffness was found. When the value of the stiffness is close to the limit value, the corresponding boundary condition is illustrated. An ADAMS experiment was carried out to check the theory and the simulation.

  9. Scanning Tunneling Microscope For Use In Vacuum

    Science.gov (United States)

    Abel, Phillip B.

    1993-01-01

    Scanning tunneling microscope with subangstrom resolution developed to study surface structures. Although instrument used in air, designed especially for use in vacuum. Scanning head is assembly of small, mostly rigid components made of low-outgassing materials. Includes coarse-positioning mechanical-translation stage, on which specimen mounted by use of standard mounting stub. Tunneling tip mounted on piezoelectric fine-positioning tube. Application of suitable voltages to electrodes on piezoelectric tube controls scan of tunneling tip across surface of specimen. Electronic subsystem generates scanning voltages and collects data.

  10. Sports Dehydration Safety Tips

    Science.gov (United States)

    Sports Dehydration Safety Tips Everything you need to know to keep your kids safe from dehydration when playing sports. To keep kids in top ... to stay hydrated by drinking plenty of fluids. Dehydration occurs when a body loses more water than ...

  11. Fabrication Effects on Polysilicon-based Micro cantilever Piezo resistivity for Biological Sensing Application

    International Nuclear Information System (INIS)

    Nina Korlina Madzhi; Balkish Natra; Mastura Sidek; Khuan, L.Y.; Anuar Ahmad

    2011-01-01

    In principle, adsorption of biological molecules on a functionalized surface of a micro fabricated cantilever will cause a surface stress and consequently the cantilever bending. In this work, four different type of polysilicon-based piezo resistive micro cantilever sensors were designed to increase the sensitivity of the micro cantilevers sensor because the forces involved is very small. The design and optimization was performed by using finite element analysis to maximize the relative resistance changes of the piezo resistors as a function of the cantilever vertical displacements. The resistivity of the piezo resistivity micro cantilevers was analyzed before and after dicing process. The maximum resistance changes were systematically investigated by varying the piezo resistor length. The results show that although the thickness of piezo resistor was the same at 0.5 μm the resistance value was varied. (author)

  12. Investigations on antibody binding to a micro-cantilever coated with a BAM pesticide residue

    Directory of Open Access Journals (Sweden)

    Aamand Jens

    2011-01-01

    Full Text Available Abstract The attachment of an antibody to an antigen-coated cantilever has been investigated by repeated experiments, using a cantilever-based detection system by Cantion A/S. The stress induced by the binding of a pesticide residue BAM (2,6 dichlorobenzamide immobilized on a cantilever surface to anti-BAM antibody is measured using the CantiLab4© system from Cantion A/S with four gold-coated cantilevers and piezo resistive readout. The detection mechanism is in principle label-free, but fluorescent-marked antibodies have been used to subsequently verify the binding on the cantilever surface. The bending and increase in mass of each cantilever has also been investigated using a light interferometer and a Doppler Vibrometer. The system has been analyzed during repeated measurements to investigate whether the CantiLab4© system is a suited platform for a pesticide assay system.

  13. A Review on Surface Stress-Based Miniaturized Piezoresistive SU-8 Polymeric Cantilever Sensors

    Science.gov (United States)

    Mathew, Ribu; Ravi Sankar, A.

    2018-06-01

    In the last decade, microelectromechanical systems (MEMS) SU-8 polymeric cantilevers with piezoresistive readout combined with the advances in molecular recognition techniques have found versatile applications, especially in the field of chemical and biological sensing. Compared to conventional solid-state semiconductor-based piezoresistive cantilever sensors, SU-8 polymeric cantilevers have advantages in terms of better sensitivity along with reduced material and fabrication cost. In recent times, numerous researchers have investigated their potential as a sensing platform due to high performance-to-cost ratio of SU-8 polymer-based cantilever sensors. In this article, we critically review the design, fabrication, and performance aspects of surface stress-based piezoresistive SU-8 polymeric cantilever sensors. The evolution of surface stress-based piezoresistive cantilever sensors from solid-state semiconductor materials to polymers, especially SU-8 polymer, is discussed in detail. Theoretical principles of surface stress generation and their application in cantilever sensing technology are also devised. Variants of SU-8 polymeric cantilevers with different composition of materials in cantilever stacks are explained. Furthermore, the interdependence of the material selection, geometrical design parameters, and fabrication process of piezoresistive SU-8 polymeric cantilever sensors and their cumulative impact on the sensor response are also explained in detail. In addition to the design-, fabrication-, and performance-related factors, this article also describes various challenges in engineering SU-8 polymeric cantilevers as a universal sensing platform such as temperature and moisture vulnerability. This review article would serve as a guideline for researchers to understand specifics and functionality of surface stress-based piezoresistive SU-8 cantilever sensors.[Figure not available: see fulltext.

  14. On the electromechanical modelling of a resonating nano-cantilever-based transducer

    DEFF Research Database (Denmark)

    Teva, J.; Abadal, G.; Davis, Zachary James

    2004-01-01

    deflection and the frequency response of the oscillation amplitude for different voltage polarization conditions. For the electrostatic force calculation the model takes into account the real deflection shape of the cantilever and the contribution to the cantilever-driver capacitance of the fringing field....... Both the static and dynamic predictions have been validated experimentally by measuring the deflection of the cantilever by means of an optical microscope. (C) 2004 Elsevier B.V. All rights reserved....

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... or bypass, without the risks that accompany open surgery. TIPS is a minimally invasive procedure that typically has a shorter recovery time than surgery. Your TIPS should have less of an effect ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... then placed in this tunnel to keep the pathway open. Patients who typically need a TIPS have ... and stomach. A TIPS procedure involves creating a pathway through the liver that connects the portal vein ( ...

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... and/or hydrothorax (in the chest). Budd-Chiari syndrome , a blockage in one or more veins that ... intentionally to solve the problem. Although extremely rare, children may also require a TIPS procedure. TIPS in ...

  18. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... filtered out by the liver. The TIPS may cause too much of these substances to bypass the ...

  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... the esophagus and stomach. A TIPS procedure involves creating a pathway through the liver that connects the ... diseases. This can result in significant challenges in creating the TIPS. top of page Additional Information and ...

  20. Tips for Living with Scleroderma

    Science.gov (United States)

    ... Patients Tips for Living Tips for Living with Scleroderma Ways to help manage your symptoms The Scleroderma ... help find improved therapies and a cure for scleroderma! Your gift today will be matched to have ...

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... TIPS. top of page What are some common uses of the procedure? A TIPS is used to ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  2. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

    Medline Plus

    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... recovery time than surgery. Your TIPS should have less of an effect than open surgical bypass on ...

  3. Scanning tunneling microscope nanoetching method

    Science.gov (United States)

    Li, Yun-Zhong; Reifenberger, Ronald G.; Andres, Ronald P.

    1990-01-01

    A method is described for forming uniform nanometer sized depressions on the surface of a conducting substrate. A tunneling tip is used to apply tunneling current density sufficient to vaporize a localized area of the substrate surface. The resulting depressions or craters in the substrate surface can be formed in information encoding patterns readable with a scanning tunneling microscope.

  4. Nuclear Scans

    Science.gov (United States)

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  5. Scanning tunneling microscope assembly, reactor, and system

    Science.gov (United States)

    Tao, Feng; Salmeron, Miquel; Somorjai, Gabor A

    2014-11-18

    An embodiment of a scanning tunneling microscope (STM) reactor includes a pressure vessel, an STM assembly, and three spring coupling objects. The pressure vessel includes a sealable port, an interior, and an exterior. An embodiment of an STM system includes a vacuum chamber, an STM reactor, and three springs. The three springs couple the STM reactor to the vacuum chamber and are operable to suspend the scanning tunneling microscope reactor within the interior of the vacuum chamber during operation of the STM reactor. An embodiment of an STM assembly includes a coarse displacement arrangement, a piezoelectric fine displacement scanning tube coupled to the coarse displacement arrangement, and a receiver. The piezoelectric fine displacement scanning tube is coupled to the coarse displacement arrangement. The receiver is coupled to the piezoelectric scanning tube and is operable to receive a tip holder, and the tip holder is operable to receive a tip.

  6. Cantilever-based micro-particle filter with simultaneous single particle detection

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2011-01-01

    Currently, separation of whole blood samples on lab-on-a-chip systems is achieved via filters followed by analysis of the filtered matter such as counting of blood cells. Here, a micro-chip based on cantilever technology is developed, which enables simultaneous filtration and counting of micro-particles...... from a liquid. A hole-array is integrated into a micro-cantilever, which is inserted into a microfluidic channel perpendicular to the flow. A metal pad at the apex of the cantilever enables an optical read-out of the deflection of the cantilever. When a micro-particle is too large to pass a hole...

  7. Tip-modified Propellers

    DEFF Research Database (Denmark)

    Andersen, Poul

    1999-01-01

    The paper deals with tip-modified propellers and the methods which, over a period of two decades, have been applied to develop such propellers. The development is driven by the urge to increase the efficiency of propellers and can be seen as analogous to fitting end plates and winglets to aircraft...... propeller, have efficiency increases of a reasonable magnitude in both open-water and behind-ship conditions....

  8. Atomic force microscope cantilever as an encoding sensor for real-time displacement measurement

    International Nuclear Information System (INIS)

    Chen, Xiaomei; Koenders, Ludger; Wolff, Helmut; Haertig, Frank; Schilling, Meinhard

    2010-01-01

    A tuning fork-based atomic force microscope cantilever has been investigated for application as an encoding sensor for real-time displacement measurement. The algorithm used to encode the displacement is based on the direct count of the integer pitches of a known grating, and the calculation of the fractional parts of a pitch at the beginning and during displacement. A cross-correlation technique has been adopted and applied to the real-time signal filtering process for the determination of the pitch during scanning by using a half sinusoidal waveform template. For the first investigation, a 1D sinusoidal grating with the pitch of 300 nm is used. The repeatability of displacement measurements over a distance of 70 µm is better than 2.2 nm. As the first application, the real-time displacement of a scanning stage is measured by the new encoding principle as it is moved in an open-loop mode and closed-loop mode based on its built-in capacitance sensor

  9. Determining mode I cohesive law of Pinus pinaster by coupling double cantilever beam test with digital image correlation

    Directory of Open Access Journals (Sweden)

    J. Xavier

    2015-01-01

    Full Text Available The direct identification of the cohesive law in pure mode I of Pinus pinaster is addressed. The approach couples the double cantilever beam (DCB test with digital image correlation (DIC. Wooden beam specimens loaded in the radial-longitudinal (RL fracture propagation system are used. The strain energy release rate in mode I ( is uniquely determined from the load-displacement ( curve by means of the compliance-based beam method (CBBM. This method relies on the concept of equivalent elastic crack length ( and therefore does not require the monitoring of crack propagation during test. The crack tip opening displacement in mode I is determined from the displacement field at the initial crack tip. The cohesive law in mode I is then identified by numerical differentiation of the relationship. Moreover, the proposed procedure is validated by finite element analyses including cohesive zone modelling. It is concluded that the proposed data reduction scheme is adequate for assessing the cohesive law in pure mode I of P. pinaster

  10. Intermittent-contact scanning capacitance microscopy imaging and modeling for overlay metrology

    International Nuclear Information System (INIS)

    Mayo, S.; Kopanski, J. J.; Guthrie, W. F.

    1998-01-01

    Overlay measurements of the relative alignment between sequential layers are one of the most critical issues for integrated circuit (IC) lithography. We have implemented on an AFM platform a new intermittent-contact scanning capacitance microscopy (IC-SCM) mode that is sensitive to the tip proximity to an IC interconnect, thus making it possible to image conductive structures buried under planarized dielectric layers. Such measurements can be used to measure IC metal-to-resist lithography overlay. The AFM conductive cantilever probe oscillating in a vertical plane was driven at frequency ω, below resonance. By measuring the tip-to-sample capacitance, the SCM signal is obtained as the difference in capacitance, ΔC(ω), at the amplitude extremes. Imaging of metallization structures was obtained with a bars-in-bars aluminum structure embedded in a planarized dielectric layer 1 μm thick. We have also modeled, with a two-dimensional (2D) electrostatic field simulator, IC-SCM overlay data of a metallization structure buried under a planarized dielectric having a patterned photoresist layer deposited on it. This structure, which simulates the metal-to-resist overlay between sequential IC levels, allows characterization of the technique sensitivity. The capacitance profile across identical size electrically isolated or grounded metal lines embedded in a dielectric was shown to be different. The floating line shows capacitance enhancement at the line edges, with a minimum at the line center. The grounded line shows a single capacitance maximum located at the line center, with no edge enhancement. For identical line dimensions, the capacitance is significantly larger for grounded lines making them easier to image. A nonlinear regression algorithm was developed to extract line center and overlay parameters with approximately 3 nm resolution at the 95% confidence level, showing the potential of this technique for sub-micrometer critical dimension metrology. Symmetric test

  11. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    Directory of Open Access Journals (Sweden)

    Valeria Toffoli

    2013-12-01

    Full Text Available The design and characteristics of a micro-system for thermogravimetric analysis (TGA in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

  12. Piezoelectric Bimorph Cantilever for Vibration-Producing-Hydrogen

    Directory of Open Access Journals (Sweden)

    Guangming Cheng

    2012-12-01

    Full Text Available A device composed of a piezoelectric bimorph cantilever and a water electrolysis device was fabricated to realize piezoelectrochemical hydrogen production. The obvious output of the hydrogen and oxygen through application of a mechanical vibration of ~0.07 N and ~46.2 Hz was observed. This method provides a cost-effective, recyclable, environment-friendly and simple way to directly split water for hydrogen fuels by scavenging mechanical waste energy forms such as noise or traffic vibration in the environment.

  13. Micro-cantilever flow sensor for small aircraft

    KAUST Repository

    Ghommem, Mehdi; Calo, Victor M.; Claudel, Christian G.

    2013-01-01

    We extend the use of cantilever beams as flow sensors for small aircraft. As such, we propose a novel method to measure the airspeed and the angle of attack at which the air travels across a small flying vehicle. We measure beam deflections and extract information about the surrounding flow. Thus, we couple a nonlinear beam model with a potential flow simulator through a fluid-structure interaction scheme. We use this numerical approach to generate calibration curves that exhibit the trend for the variations of the limit cycle oscillations amplitudes of flexural and torsional vibrations with the air speed and the angle of attack, respectively. © The Author(s) 2013.

  14. APPARATUS FOR NON-DESTRUCTIVE INSPECTION OF CANTILEVERED MEMBERS

    Science.gov (United States)

    Taylor, E.R.; Mahoney, C.H.; Lay, C.R.

    1961-10-24

    An apparatus for non-destructive inspection of cantilevered members, such as compressor blades, is described. The member under inspection is vibrated with a regulated source of air under pressure. The amplitude of vibration of the member is maintained at its natural frequency. The frequency of vibration of the member is measured. An indication of an excessive decay or erratic shifting in the measured frequency above an allowable hysteretic decay is provided as an indication of a fault in the member. The member is vibrated for a selected test period. (AEC)

  15. Heater-Integrated Cantilevers for Nano-Samples Thermogravimetric Analysis

    Science.gov (United States)

    Toffoli, Valeria; Carrato, Sergio; Lee, Dongkyu; Jeon, Sangmin; Lazzarino, Marco

    2013-01-01

    The design and characteristics of a micro-system for thermogravimetric analysis (TGA) in which heater, temperature sensor and mass sensor are integrated into a single device are presented. The system consists of a suspended cantilever that incorporates a microfabricated resistor, used as both heater and thermometer. A three-dimensional finite element analysis was used to define the structure parameters. TGA sensors were fabricated by standard microlithographic techniques and tested using milli-Q water and polyurethane microcapsule. The results demonstrated that our approach provides a faster and more sensitive TGA with respect to commercial systems.

  16. Desain Cantilever Beam Piezoelectric Untuk Aplikasi Energi Harvesting

    Directory of Open Access Journals (Sweden)

    Roer Pawinanto

    2016-12-01

    Full Text Available Material piezoelektrik sudah mulai diaplkasikan dalam beberapa aplikasi seperti sebagai transduser untuk energi harvesting. Dalam studi ini kami menggunakan metode FEA untuk mengoptimasi beam piezoelektrik. Defleksi yang diperoleh pada studi ini yaitu sebesar 83 nm manakala frekuensi resonansi nya diperoleh di 13.4 Hz. Material piezoelektrik ini dapat menghasilkan defleksi yang besar ketika bergetar pada frekuensi resonansinya. Hasil optimisasi juga menunjukkan bahwa daya listrik yang dihasilkan mengindikasikan resistansi yang besar juga dan berkaitan dengan panjang material PZT serta dapat mempengaruhi defleksi dari cantilever beam.

  17. Analytical simulation of the cantilever-type energy harvester

    Directory of Open Access Journals (Sweden)

    Jie Mei

    2016-01-01

    Full Text Available This article describes an analytical model of the cantilever-type energy harvester based on Euler–Bernoulli’s beam theory. Starting from the Hamiltonian form of total energy equation, the bending mode shapes and electromechanical dynamic equations are derived. By solving the constitutive electromechanical dynamic equation, the frequency transfer function of output voltage and power can be obtained. Through a case study of a unimorph piezoelectric energy harvester, this analytical modeling method has been validated by the finite element method.

  18. Micro-cantilever flow sensor for small aircraft

    KAUST Repository

    Ghommem, Mehdi

    2013-10-01

    We extend the use of cantilever beams as flow sensors for small aircraft. As such, we propose a novel method to measure the airspeed and the angle of attack at which the air travels across a small flying vehicle. We measure beam deflections and extract information about the surrounding flow. Thus, we couple a nonlinear beam model with a potential flow simulator through a fluid-structure interaction scheme. We use this numerical approach to generate calibration curves that exhibit the trend for the variations of the limit cycle oscillations amplitudes of flexural and torsional vibrations with the air speed and the angle of attack, respectively. © The Author(s) 2013.

  19. Size-dependent effective Young’s modulus of silicon nitride cantilevers

    NARCIS (Netherlands)

    Babaei Gavan, K.; Westra, H.J.R.; Van der Drift, E.W.J.M.; Venstra, W.J.; Van der Zant, H.S.J.

    2009-01-01

    The effective Young’s modulus of silicon nitride cantilevers is determined for thicknesses in the range of 20–684 nm by measuring resonance frequencies from thermal noise spectra. A significant deviation from the bulk value is observed for cantilevers thinner than 150 nm. To explain the observations

  20. Optical device comprising a cantilever and method of fabrication and use thereof

    NARCIS (Netherlands)

    Iannuzzi, Davide; Deladi, S.; Elwenspoek, Michael Curt

    2008-01-01

    The present invention provides an optical device, comprising an optical fiber and a cantilever that is arranged on an end of the optical fiber; The cantilever may be an integral part of the optical fiber, and may have a length that is substantially equal to a diameter of the optical fiber.

  1. Optical device comprising a cantilever and method of fabrication and use thereof

    NARCIS (Netherlands)

    Iannuzzi, Davide; Deladi, S.; Elwenspoek, Michael Curt

    2011-01-01

    The present invention provides an optical device, comprising an optical fiber and a cantilever that is arranged on an end of the optical fiber; The cantilever may be an integral part of the optical fiber, and may have a length that is substantially equal to a diameter of the optical fiber.

  2. A new approach to integrate PLZT thin films with micro-cantilevers

    Indian Academy of Sciences (India)

    Home; Journals; Sadhana; Volume 34; Issue 4. A new approach to integrate PLZT thin films with micro-cantilevers ... Different types of cantilever beams incorporating PLZT films have been successfully fabricated using 'lift-off' process and bulk micromachining technology. The proposed process can be advantageously ...

  3. Determination of young's modulus of PZT-influence of cantilever orientation

    NARCIS (Netherlands)

    Nazeer, H.; Woldering, L.A.; Abelmann, Leon; Elwenspoek, Michael Curt

    Calculation of the resonance frequency of cantilevers fabricated from an elastically anisotropic material requires the use of an effective Young’s modulus. In this paper a technique to determine the appropriate effective Young’s modulus for arbitrary cantilever geometries is introduced. This

  4. Investigations on antibody binding to a micro-cantilever coated with a BAM pesticide residue

    DEFF Research Database (Denmark)

    Bache, Michael; Taboryski, Rafael Jozef; Schmid, Silvan

    2011-01-01

    -BAM antibody is measured using the CantiLab4© system from Cantion A/S with four gold-coated cantilevers and piezo resistive readout. The detection mechanism is in principle label-free, but fluorescent-marked antibodies have been used to subsequently verify the binding on the cantilever surface. The bending...

  5. A novel fabrication technique for free-hanging homogeneous polymeric cantilever waveguides

    DEFF Research Database (Denmark)

    Nordström, M.; Calleja, M.; Hübner, Jörg

    2008-01-01

    We present a novel bonding technique developed for the fabrication of a cantilever-based biosensing system with integrated optical read-out. The read-out mechanism is based on single-mode waveguides fabricated monolithically in SU-8. For optimal operation of the read-out mode, the cantilever...

  6. Monolithic Concrete vs Precast Concrete for the Construction of Bridge by Th Cantilever Method

    Directory of Open Access Journals (Sweden)

    Morlova Dumitru Daniel

    2015-07-01

    Full Text Available In the article "Monolithic Concrete vs Precast Concrete for the Construction of Bridges by the Cantilever Method", there are approached a number of issues that come out in the design and execution of prestressed concrete bridge structures using the cantilever method.

  7. Silicon technology-based micro-systems for atomic force microscopy/photon scanning tunnelling microscopy.

    Science.gov (United States)

    Gall-Borrut, P; Belier, B; Falgayrettes, P; Castagne, M; Bergaud, C; Temple-Boyer, P

    2001-04-01

    We developed silicon nitride cantilevers integrating a probe tip and a wave guide that is prolonged on the silicon holder with one or two guides. A micro-system is bonded to a photodetector. The resulting hybrid system enables us to obtain simultaneously topographic and optical near-field images. Examples of images obtained on a longitudinal cross-section of an optical fibre are shown.

  8. Instability of a cantilevered flexible plate in viscous channel flow

    Science.gov (United States)

    Balint, T. S.; Lucey, A. D.

    2005-10-01

    The stability of a flexible cantilevered plate in viscous channel flow is studied as a representation of the dynamics of the human upper airway. The focus is on instability mechanisms of the soft palate (flexible plate) that cause airway blockage during sleep. We solve the Navier Stokes equations for flow with Reynolds numbers up to 1500 fully coupled with the dynamics of the plate motion solved using finite-differences. The study is 2-D and based upon linearized plate mechanics. When both upper and lower airways are open, the plate is found to lose its stability through a flutter mechanism and a critical Reynolds number exists. When one airway is closed, the plate principally loses its stability through a divergence mechanism and a critical flow speed exists. However, below the divergence-onset flow speed, flutter can exist for low levels of structural damping in the flexible plate. Our results serve to extend understanding of flow-induced instability of cantilevered flexible plates and will ultimately improve the diagnosis and treatment of upper-airway disorders.

  9. Fluid-structure interactions of photo-responsive polymer cantilevers

    Science.gov (United States)

    Bin, Jonghoon; Oates, William S.; Yousuff Hussaini, M.

    2013-02-01

    A new class of photomechanical liquid crystal networks (LCNs) has emerged, which generate large bending deformation and fast response times that scale with the resonance of the polymer films. Here, a numerical study is presented that describes the photomechanical structural dynamic behavior of an LCN in a fluid medium; however, the methodology is also applicable to fluid-structure interactions of a broader range of adaptive structures. Here, we simulate the oscillation of photomechanical cantilevers excited by light while simultaneously modeling the effect of the surrounding fluid at different ambient pressures. The photoactuated LCN is modeled as an elastic thin cantilever plate, and gradients in photostrain from the external light are computed from the assumptions of light absorption and photoisomerization through the film thickness. Numerical approximations of the equations governing the plate are based on cubic B-spline shape functions and a second order implicit Newmark central scheme for time integration. For the fluid, three dimensional unsteady incompressible Navier-Stokes equations are solved using the arbitrary Lagrangian-Eulerian (ALE) method, which employs a structured body-fitted curvilinear coordinate system where the solid-fluid interface is a mesh line of the system, and the complicated interface boundary conditions are accommodated in a conventional finite-volume formulation. Numerical examples are given which provide new insight into material behavior in a fluid medium as a function of ambient pressure.

  10. Higher Order Modes Excitation of Micro Cantilever Beams

    KAUST Repository

    Jaber, Nizar

    2014-05-01

    In this study, we present analytical and experimental investigation of electrically actuated micro cantilever based resonators. These devices are fabricated using polyimide and coated with chrome and gold layers from both sides. The cantilevers are highly curled up due to stress gradient, which is a common imperfection in surface micro machining. Using a laser Doppler vibrometer, we applied a noise signal to experimentally find the first four resonance frequencies. Then, using a data acquisition card, we swept the excitation frequency around the first four natural modes of vibrations. Theoretically, we derived a reduced order model using the Galerkin method to simulate the dynamics of the system. Extensive numerical analysis and computations were performed. The numerical analysis was able to provide good matching with experimental values of the resonance frequencies. Also, we proved the ability to excite higher order modes using partial electrodes with shapes that resemble the shape of the mode of interest. Such micro-resonators are shown to be promising for applications in mass and gas sensing.

  11. A piezoresistive cantilever for lateral force detection fabricated by a monolithic post-CMOS process

    International Nuclear Information System (INIS)

    Ji Xu; Li Zhihong; Li Juan; Wang Yangyuan; Xi Jianzhong

    2008-01-01

    This paper presents a post-CMOS process to monolithically integrate a piezoresistive cantilever for lateral force detection and signal processing circuitry. The fabrication process includes a standard CMOS process and one more lithography step to micromachine the cantilever structure in the post-CMOS process. The piezoresistors are doped in the CMOS process but defined in the post-CMOS micromachining process without any extra process required. A partially split cantilever configuration is developed for the lateral force detection. The piezoresistors are self-aligned to the split cantilever, and therefore the width of the beam is only limited by lithography. Consequently, this kind of cantilever potentially has a high resolution. The preliminary experimental results show expected performances of the fabricated piezoresistors and electronic circuits

  12. Controlling the opto-mechanics of a cantilever in an interferometer via cavity loss

    Energy Technology Data Exchange (ETDEWEB)

    Schmidsfeld, A. von, E-mail: avonschm@uos.de; Reichling, M., E-mail: reichling@uos.de [Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück (Germany)

    2015-09-21

    In a non-contact atomic force microscope, based on interferometric cantilever displacement detection, the optical return loss of the system is tunable via the distance between the fiber end and the cantilever. We utilize this for tuning the interferometer from a predominant Michelson to a predominant Fabry-Pérot characteristics and introduce the Fabry-Pérot enhancement factor as a quantitative measure for multibeam interference in the cavity. This experimentally easily accessible and adjustable parameter provides a control of the opto-mechanical interaction between the cavity light field and the cantilever. The quantitative assessment of the light pressure acting on the cantilever oscillating in the cavity via the frequency shift allows an in-situ measurement of the cantilever stiffness with remarkable precision.

  13. Single cell adhesion force measurement for cell viability identification using an AFM cantilever-based micro putter

    Science.gov (United States)

    Shen, Yajing; Nakajima, Masahiro; Kojima, Seiji; Homma, Michio; Kojima, Masaru; Fukuda, Toshio

    2011-11-01

    Fast and sensitive cell viability identification is a key point for single cell analysis. To address this issue, this paper reports a novel single cell viability identification method based on the measurement of single cell shear adhesion force using an atomic force microscopy (AFM) cantilever-based micro putter. Viable and nonviable yeast cells are prepared and put onto three kinds of substrate surfaces, i.e. tungsten probe, gold and ITO substrate surfaces. A micro putter is fabricated from the AFM cantilever by focused ion beam etching technique. The spring constant of the micro putter is calibrated using the nanomanipulation approach. The shear adhesion force between the single viable or nonviable cell and each substrate is measured using the micro putter based on the nanorobotic manipulation system inside an environmental scanning electron microscope. The adhesion force is calculated based on the deflection of the micro putter beam. The results show that the adhesion force of the viable cell to the substrate is much larger than that of the nonviable cell. This identification method is label free, fast, sensitive and can give quantitative results at the single cell level.

  14. The Mechanics of a Cantilever Beam with an Embedded Horizontal Crack Subjected to an End Transverse Force, Part A: Modelling

    Directory of Open Access Journals (Sweden)

    Panos G. Charalambides

    2016-05-01

    Full Text Available This study addresses the mechanics of a cracked cantilever beam subjected to a transverse force applied at it’s free end. In this Part A of a two Part series of papers, emphasis is placed on the development of a four-beam model for a beam with a fully embedded horizontal sharp crack. The beam aspect ratio, crack length and crack centre location appear as general model parameters. Rotary springs are introduced at the crack tip cross sections as needed to account for the changes in the structural compliance due to the presence of the sharp crack and augmented load transfer through the near-tip transition regions. Guided by recent finite element findings reported elsewhere, the four-beam model is advanced by recognizing two key observations, (a the free surface and neutral axis curvatures of the cracked beam at the crack center location match the curvature of a healthy beam (an identical beam without a crack under the same loading conditions, (b the neutral axis rotations (slope of the cracked beam in the region between the applied load and the nearest crack tip matches the corresponding slope of the healthy beam. The above observations led to the development of close form solutions for the resultant forces (axial and shear and moment acting in the beams above and below the crack. Axial force and bending moment predictions are found to be in excellent agreement with 2D finite element results for all normalized crack depths considered. Shear force estimates dominating the beams above and below the crack as well as transition region length estimates are also obtained. The model developed in this study is then used along with 2D finite elements in conducting parametric studies aimed at both validating the model and establishing the mechanics of the cracked system under consideration. The latter studies are reported in the companion paper Part B-Results and Discussion.

  15. Interaction forces and conduction properties between multi wall carbon nanotube tips and Au(1 1 1)

    Energy Technology Data Exchange (ETDEWEB)

    Luna, M.; Pablo, P.J. de; Colchero, J.; Gomez-Herrero, J.; Baro, A.M.; Tokumoto, H.; Jarvis, S.P

    2003-07-15

    We have studied the interaction forces and electrical conduction properties arising between multiwall carbon nanotube tips and the Au(1 1 1) surface in air, by means of amplitude modulation scanning force microscopy, also called intermittent contact. We have centered our work on tips with metallic electronic structure and for the specific parameters used we have found a preliminary interaction range where there is no contact between tip and surface. Stable imaging in this non-contact range is possible with multiwall carbon nanotube tips. These tips have also been used to obtain simultaneous topographic and current maps of the surface. They show excellent properties as tips due to their high aspect ratio and durability, as a result of their elastic and non-reactive properties. Correspondingly, multiwall carbon nanotube tips allow high resolution local analysis of electrical conductivity on a nanometer scale.

  16. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  17. Renal scan

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003790.htm Renal scan To use the sharing features on this ... anaphylaxis . Alternative Names Renogram; Kidney scan Images Kidney anatomy Kidney - blood and urine flow References Chernecky CC, ...

  18. CT Scan

    Science.gov (United States)

    ... disease, lung nodules and liver masses Monitor the effectiveness of certain treatments, such as cancer treatment Detect ... scan done in a hospital or an outpatient facility. CT scans are painless and, with newer machines, ...

  19. Interface debonding characterization by image correlation integrated with Double Cantilever Beam kinematics

    KAUST Repository

    Blaysat, Benoît

    2015-03-01

    A procedure is proposed for the identification of spatial interfacial traction profiles of peel loaded Double Cantilever Beam (DCB) samples, from which the corresponding traction-separation relation is extracted. The procedure draws upon recent developments in the area of non-contact optical techniques and makes use of so-called Integrated Digital Image Correlation (I-DIC) concepts. The distinctive feature of the I-DIC approach proposed herein is that the unknown degrees of freedom are not displacements or rotations, but the set of interfacial fracture properties describing the traction profile. A closed-form theoretical model is developed to reconstruct a mechanically admissible displacement field representing the deformation of the adhering layers during debonding in the DCB fracture test. The proposed modeling accounts for the spatial traction profile along the interface between the adherends using few degrees of freedom, i.e. crack tip position, maximum stress and size of the process zone. By minimizing the correlation residual with respect to the degrees of freedom, the full set of interfacial fracture properties is obtained through a one-step algorithm, revealing a substantial gain in terms of computational efficiency and robustness. It is shown that the identified traction profile can be effectively combined with the crack opening displacement to extract the corresponding traction-separation relation, i.e. the key input data for any cohesive zone model (CZM). The proposed procedure is validated by post-processing virtually deformed images generated through the finite element method. The robustness with respect to noisy data, as well as the low sensitivity to the initial guess, are demonstrated.

  20. Preparation of platinum/iridium scanning probe microscopy tips

    DEFF Research Database (Denmark)

    Sørensen, Alexis Hammer; Hvid, U.; Mortensen, M.W.

    1999-01-01

    oxide layer. In order to explain the relatively high etching rates observed for the otherwise noble metal platinum we suggest that besides anodic corrosion of the platinum by the electrolyte containing chloride ions, a different etching mechanism causes a substantial increase of the etching rate...

  1. Tips for Starting Physical Activity

    Science.gov (United States)

    ... Legislative Information Advisory & Coordinating Committees Strategic Plans & Reports Research Areas FAQs ... Starting Physical Activity Related Topics Section Navigation Tips to Help You Get Active ...

  2. 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...

  3. Simulation of high-resolution MFM tip using exchange-spring magnet

    Energy Technology Data Exchange (ETDEWEB)

    Saito, H. [Faculty of Resource Science and Engineering, Akita University, Akita 010-8502 (Japan)]. E-mail: hsaito@ipc.akita-u.ac.jp; Yatsuyanagi, D. [Faculty of Resource Science and Engineering, Akita University, Akita 010-8502 (Japan); Ishio, S. [Faculty of Resource Science and Engineering, Akita University, Akita 010-8502 (Japan); Ito, A. [Nitto Optical Co. Ltd., Misato, Akita 019-1403 (Japan); Kawamura, H. [Nitto Optical Co. Ltd., Misato, Akita 019-1403 (Japan); Ise, K. [Research Institute of Advanced Technology Akita, Akita 010-1623 (Japan); Taguchi, K. [Research Institute of Advanced Technology Akita, Akita 010-1623 (Japan); Takahashi, S. [Research Institute of Advanced Technology Akita, Akita 010-1623 (Japan)

    2007-03-15

    The transfer function of magnetic force microscope (MFM) tips using an exchange-spring trilayer composed of a centered soft magnetic layer and two hard magnetic layers was calculated and the resolution was estimated by considering the thermodynamic noise limit of an MFM cantilever. It was found that reducing the thickness of the centered soft magnetic layer and the magnetization of hard magnetic layer are important to obtain high resolution. Tips using an exchange-spring trilayer with a very thin FeCo layer and isotropic hard magnetic layers, such as CoPt and FePt, are found to be suitable for obtaining a resolution less than 10 nm at room temperature.

  4. 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

  5. Accurate Calibration and Uncertainty Estimation of the Normal Spring Constant of Various AFM Cantilevers

    Directory of Open Access Journals (Sweden)

    Yunpeng Song

    2015-03-01

    Full Text Available Measurement of force on a micro- or nano-Newton scale is important when exploring the mechanical properties of materials in the biophysics and nanomechanical fields. The atomic force microscope (AFM is widely used in microforce measurement. The cantilever probe works as an AFM force sensor, and the spring constant of the cantilever is of great significance to the accuracy of the measurement results. This paper presents a normal spring constant calibration method with the combined use of an electromagnetic balance and a homemade AFM head. When the cantilever presses the balance, its deflection is detected through an optical lever integrated in the AFM head. Meanwhile, the corresponding bending force is recorded by the balance. Then the spring constant can be simply calculated using Hooke’s law. During the calibration, a feedback loop is applied to control the deflection of the cantilever. Errors that may affect the stability of the cantilever could be compensated rapidly. Five types of commercial cantilevers with different shapes, stiffness, and operating modes were chosen to evaluate the performance of our system. Based on the uncertainty analysis, the expanded relative standard uncertainties of the normal spring constant of most measured cantilevers are believed to be better than 2%.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-15

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

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

    International Nuclear Information System (INIS)

    Sader, John E.; Sanelli, Julian A.; Adamson, Brian D.; Bieske, Evan J.; Monty, Jason P.; Marusic, Ivan; Wei Xingzhan; Mulvaney, Paul; Crawford, Simon A.; Friend, James R.

    2012-01-01

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

  8. Anterior Cantilever Resin-Bonded Fixed Dental Prostheses: A Review of the Literature.

    Science.gov (United States)

    Mourshed, Bilal; Samran, Abdulaziz; Alfagih, Amal; Samran, Ahalm; Abdulrab, Saleem; Kern, Matthias

    2018-03-01

    This review evaluated the survival rate of single retainer anterior resin-bonded fixed dental prostheses (RBFDPs) to determine whether the choice of material affects their clinical outcome. An electronic search of the English peer-reviewed dental literature in PubMed was conducted to identify all publications reporting on cantilever RBFDPs until May 2016. Study information extraction and methodological quality assessments were accomplished by two reviewers independently. The searched keywords were as follows: "resin-bonded, single retainer, all-ceramic resin-bonded fixed dental prostheses (RBFDPs), all-ceramic RBFDPs, cantilever resin, RBFDPs, cantilever resin-bonded bridge, two units cantilevered, two-unit cantilevered, metal-ceramic cantilever, and metal-ceramic." Furthermore, the ''Related Articles'' feature of PubMed was used to identify further references of interest within the primary search. The bibliographies of the obtained references were used to identify pertinent secondary references. Review articles were also used to identify relevant articles. After the application of exclusion criteria, the definitive list of articles was screened to extract the qualitative data, and the results were analyzed. Overall 2588 articles were dedicated at the first review phase; however, only 311 studies were left after the elimination of duplicates and unrelated studies. Seventeen studies passed the second review phase. Five studies were excluded because they were follow-up studies of the same study cohort. Twelve studies were finally selected. The use of cantilever RBFDPs showed promising results and high survival rates. © 2016 by the American College of Prosthodontists.

  9. Experiments of flow-induced in-line oscillation of a circular cylinder in a water tunnel. 2. Influence of the aspect ratio of a cantilevered circular cylinder

    International Nuclear Information System (INIS)

    Nakamura, Akira; Okajima, Atsushi; Kosugi, Takashi

    2001-01-01

    The flow-induced in-line oscillation of a cantilevered circular cylinder was experimentally studied through free-oscillation tests in a water tunnel. The response displacement amplitude at a circular cylinder tip was measured at reduced velocity from 1.0 to 4.0. A cantilevered cylinder was supported by a plate spring mounted on the water tunnel wall. The cylinder aspect ratio was varied from 5 to 21 to investigate the effect of aspect ratio on the response displacement. It is found that cylinders with aspect ratios of 5 and 10 have one excitation region, while cylinders with aspect ratios of 14 and 21 have two excitation regions. The aspect ratio, therefore, affects the amplitude of the excitation regions. The influence of end-effect was also investigated using cylinders with an end plate attached to the free end. Since the cylinders with an end plate show two excitation regions, even at an aspect ratio of 5, the flow around the free end of a cantilevered cylinder causes the end-effect. The mechanism of vibration was investigated using a cylinder with a splitter plate in wake to prevent alternate vortices. The amplitude is greater than those of a normal cylinder without a splitter plate, especially at V r =2.3 to 3.0, where a cylinder with an end plate shows the second excitation region. In order words, the alternate vortices suppress the amplitude in this range. The maximum amplitude of each excitation region decreases in proportion to C n and the amplitude of the first excitation is more sensitive to C n . (author)

  10. Investigation of Subcombination Internal Resonances in Cantilever Beams

    Directory of Open Access Journals (Sweden)

    Haider N. Arafat

    1998-01-01

    Full Text Available Activation of subcombination internal resonances in transversely excited cantilever beams is investigated. The effect of geometric and inertia nonlinearities, which are cubic in the governing equation of motion, is considered. The method of time-averaged Lagrangian and virtual work is used to determine six nonlinear ordinary-differential equations governing the amplitudes and phases of the three interacting modes. Frequency- and force-response curves are generated for the case ω ≈ ω4 ≈ 1/2(ω2 + ω5. There are two possible responses: single-mode and three-mode responses. The single-mode periodic response is found to undergo supercritical and subcritical pitchfork bifurcations, which result in three-mode interactions. In the case of three-mode responses, there are conditions where the low-frequency mode dominates the response, resulting in high-amplitude quasiperiodic oscillations.

  11. Strategy Guideline: Quality Management in Existing Homes; Cantilever Floor Example

    Energy Technology Data Exchange (ETDEWEB)

    Taggart, J.; Sikora, J.; Wiehagen, J.; Wood, A.

    2011-12-01

    This guideline is designed to highlight the QA process that can be applied to any residential building retrofit activity. The cantilevered floor retrofit detailed in this guideline is included only to provide an actual retrofit example to better illustrate the QA activities being presented. The goal of existing home high performing remodeling quality management systems (HPR-QMS) is to establish practices and processes that can be used throughout any remodeling project. The research presented in this document provides a comparison of a selected retrofit activity as typically done versus that same retrofit activity approached from an integrated high performance remodeling and quality management perspective. It highlights some key quality management tools and approaches that can be adopted incrementally by a high performance remodeler for this or any high performance retrofit. This example is intended as a template and establishes a methodology that can be used to develop a portfolio of high performance remodeling strategies.

  12. Photothermal cantilever deflection spectroscopy of a photosensitive polymer

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Minhyuk; Lee, Dongkyu; Jung, Namchul; Jeon, Sangmin [Department of Chemical Engineering, Pohang University of Science and Technology, Pohang (Korea, Republic of); Kim, Seonghwan; Chae, Inseok; Thundat, Thomas [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)

    2012-05-14

    The mechanical and chemical information of a poly(methyl methacrylate) (PMMA) film on a microcantilever were simultaneously acquired by photothermal cantilever deflection spectroscopy as a function of ultraviolet (UV) irradiation time. Nanomechanical infrared (IR) spectra from the PMMA-coated microcantilever agreed well with the Fourier transform infrared spectroscopy (FTIR) spectra of PMMA on gold-coated silicon wafer. The decreasing intensities of nanomechanical IR peaks represent chemical as well as mechanical information of UV radiation-induced photodegradation processes in the PMMA which cannot be obtained by a conventional FTIR technique. The observed decrease in the resonance frequency of the microcantilever is related to the change in the Young's modulus of the PMMA under UV exposure.

  13. Tips for Good Electronic Presentations.

    Science.gov (United States)

    Strasser, Dennis

    1996-01-01

    Describes library uses of presentation graphics software and offers tips for creating electronic presentations. Tips include: audience retention; visual aid options; software package options; presentation planning; presentation showing; and use of text, colors, and graphics. Sidebars note common presentation errors and popular presentation…

  14. A High Rigidity and Precision Scanning Tunneling Microscope with Decoupled XY and Z Scans.

    Science.gov (United States)

    Chen, Xu; Guo, Tengfei; Hou, Yubin; Zhang, Jing; Meng, Wenjie; Lu, Qingyou

    2017-01-01

    A new scan-head structure for the scanning tunneling microscope (STM) is proposed, featuring high scan precision and rigidity. The core structure consists of a piezoelectric tube scanner of quadrant type (for XY scans) coaxially housed in a piezoelectric tube with single inner and outer electrodes (for Z scan). They are fixed at one end (called common end). A hollow tantalum shaft is coaxially housed in the XY -scan tube and they are mutually fixed at both ends. When the XY scanner scans, its free end will bring the shaft to scan and the tip which is coaxially inserted in the shaft at the common end will scan a smaller area if the tip protrudes short enough from the common end. The decoupled XY and Z scans are desired for less image distortion and the mechanically reduced scan range has the superiority of reducing the impact of the background electronic noise on the scanner and enhancing the tip positioning precision. High quality atomic resolution images are also shown.

  15. A High Rigidity and Precision Scanning Tunneling Microscope with Decoupled XY and Z Scans

    Directory of Open Access Journals (Sweden)

    Xu Chen

    2017-01-01

    Full Text Available A new scan-head structure for the scanning tunneling microscope (STM is proposed, featuring high scan precision and rigidity. The core structure consists of a piezoelectric tube scanner of quadrant type (for XY scans coaxially housed in a piezoelectric tube with single inner and outer electrodes (for Z scan. They are fixed at one end (called common end. A hollow tantalum shaft is coaxially housed in the XY-scan tube and they are mutually fixed at both ends. When the XY scanner scans, its free end will bring the shaft to scan and the tip which is coaxially inserted in the shaft at the common end will scan a smaller area if the tip protrudes short enough from the common end. The decoupled XY and Z scans are desired for less image distortion and the mechanically reduced scan range has the superiority of reducing the impact of the background electronic noise on the scanner and enhancing the tip positioning precision. High quality atomic resolution images are also shown.

  16. Magnetic domain structure investigation of Bi: YIG-thin films by combination of AFM and cantilever-based aperture SNOM

    International Nuclear Information System (INIS)

    Vysokikh, Yu E; Shevyakov, V I; Krasnoborodko, S Yu; Shelaev, A V; Prokopov, A R

    2016-01-01

    We present the results of magnetic domain structure investigation by combination of atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM). Special hollow-pyramid AFM cantilevers with aperture was used. This combination allows us use same probe for both topography and domain structure visualization of Bi -substituted ferrite garnet films of micro- and nano-meter thickness. Samples were excited through aperture by tightly focused linearly polarized laser beam. Magneto-optical effect rotates polarization of transmitted light depend on domain orientation. Visualization of magnetic domains was performed by detecting cross polarized component of transmitted light. SNOM allows to obtain high resolution magnetic domain image and prevent sample from any disturbance by magnetic probe. Same area SNOM and MFM images are presented. (paper)

  17. Self-mixing interferometry in vertical-cavity surface-emitting lasers for nanomechanical cantilever sensing

    Science.gov (United States)

    Larsson, David; Greve, Anders; Hvam, Jørn M.; Boisen, Anja; Yvind, Kresten

    2009-03-01

    We have experimentally investigated self-mixing interference produced by the feedback of light from a polymer micrometer-sized cantilever into a vertical-cavity surface-emitting laser for sensing applications. In particular we have investigated how the visibility of the optical output power and the junction voltage depends on the laser injection current and the distance to the cantilever. The highest power visibility obtained from cantilevers without reflective coatings was ˜60%, resulting in a very high sensitivity of 45 mV/nm with a noise floor below 1.2 mV. Different detection schemes are discussed.

  18. Self-mixing interferometry in vertical-cavity surface-emitting lasers for nanomechanical cantilever sensing

    DEFF Research Database (Denmark)

    Larsson, David; Greve, Anders; Hvam, Jørn Märcher

    2009-01-01

    We have experimentally investigated self-mixing interference produced by the feedback of light from a polymer micrometer-sized cantilever into a vertical-cavity surface-emitting laser for sensing applications. In particular we have investigated how the visibility of the optical output power...... and the junction voltage depends on the laser injection current and the distance to the cantilever. The highest power visibility obtained from cantilevers without reflective coatings was 60%, resulting in a very high sensitivity of 45 mV/nm with a noise floor below 1.2 mV. Different detection schemes are discussed....

  19. Feedback cooling of cantilever motion using a quantum point contact transducer

    International Nuclear Information System (INIS)

    Montinaro, M.; Mehlin, A.; Solanki, H. S.; Peddibhotla, P.; Poggio, M.; Mack, S.; Awschalom, D. D.

    2012-01-01

    We use a quantum point contact (QPC) as a displacement transducer to measure and control the low-temperature thermal motion of a nearby micromechanical cantilever. The QPC is included in an active feedback loop designed to cool the cantilever's fundamental mechanical mode, achieving a squashing of the QPC noise at high gain. The minimum achieved effective mode temperature of 0.2 K and the displacement resolution of 10 -11 m/√(Hz) are limited by the performance of the QPC as a one-dimensional conductor and by the cantilever-QPC capacitive coupling.

  20. A novel fabrication technique for free-hanging homogeneous polymeric cantilever waveguides

    International Nuclear Information System (INIS)

    Nordström, Maria; Hübner, Jörg; Boisen, Anja; Calleja, Montserrat

    2008-01-01

    We present a novel bonding technique developed for the fabrication of a cantilever-based biosensing system with integrated optical read-out. The read-out mechanism is based on single-mode waveguides fabricated monolithically in SU-8. For optimal operation of the read-out mode, the cantilever waveguides should be homogenous and this bonding technique ensures free-hanging cantilevers that are surrounded by the same material for bottom and top claddings. The bonding step is necessary because SU-8 is a negative resist where free-hanging structures cannot be fabricated directly. This paper gives details on the processing aspects and the parameters of the fabrication steps

  1. Integrated MOSFET-Embedded-Cantilever-Based Biosensor Characteristic for Detection of Anthrax Simulant

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, Salwa [University of Tennessee, Knoxville (UTK); Lee, Ida [ORNL; Islam, Syed K [University of Tennessee, Knoxville (UTK); Eliza, Sazia A. [University of Tennessee, Knoxville (UTK); Shekhawat, Gajendra [Northwestern University, Evanston; Dravid, Vinayak [Northwestern University, Evanston; Tulip, Fahmida S [ORNL

    2011-01-01

    In this work, MOSFET-embedded cantilevers are configured as microbial sensors for detection of anthrax simulants, Bacillus thuringiensis. Anthrax simulants attached to the chemically treated gold-coated cantilever cause changes in the MOSFET drain current due to the bending of the cantilever which indicates the detection of anthrax simulant. Electrical properties of the anthrax simulant are also responsible for the change in the drain current. The test results suggest a detection range of 10 L of stimulant test solution (a suspension population of 1.3 107 colony-forming units/mL diluted in 40% ethanol and 60% deionized water) with a linear response of 31 A/ L.

  2. Scanning thermal microscopy based on a quartz tuning fork and a micro-thermocouple in active mode (2ω method)

    International Nuclear Information System (INIS)

    Bontempi, Alexia; Nguyen, Tran Phong; Salut, Roland; Thiery, Laurent; Teyssieux, Damien; Vairac, Pascal

    2016-01-01

    A novel probe for scanning thermal microscope using a micro-thermocouple probe placed on a Quartz Tuning Fork (QTF) is presented. Instead of using an external deflection with a cantilever beam for contact detection, an original combination of piezoelectric resonator and thermal probe is employed. Due to a non-contact photothermal excitation principle, the high quality factor of the QTF allows the probe-to-surface contact detection. Topographic and thermal scanning images obtained on a specific sample points out the interest of our system as an alternative to cantilevered resistive probe systems which are the most spread.

  3. Scanning thermal microscopy based on a quartz tuning fork and a micro-thermocouple in active mode (2ω method).

    Science.gov (United States)

    Bontempi, Alexia; Nguyen, Tran Phong; Salut, Roland; Thiery, Laurent; Teyssieux, Damien; Vairac, Pascal

    2016-06-01

    A novel probe for scanning thermal microscope using a micro-thermocouple probe placed on a Quartz Tuning Fork (QTF) is presented. Instead of using an external deflection with a cantilever beam for contact detection, an original combination of piezoelectric resonator and thermal probe is employed. Due to a non-contact photothermal excitation principle, the high quality factor of the QTF allows the probe-to-surface contact detection. Topographic and thermal scanning images obtained on a specific sample points out the interest of our system as an alternative to cantilevered resistive probe systems which are the most spread.

  4. Scanning thermal microscopy based on a quartz tuning fork and a micro-thermocouple in active mode (2ω method)

    Energy Technology Data Exchange (ETDEWEB)

    Bontempi, Alexia; Nguyen, Tran Phong; Salut, Roland; Thiery, Laurent; Teyssieux, Damien; Vairac, Pascal [FEMTO-ST Institute UMR 6174, Université de Franche-Comté, CNRS, ENSMM, UTBM, 15B Avenue des Montboucons, F-25030 Besançon (France)

    2016-06-15

    A novel probe for scanning thermal microscope using a micro-thermocouple probe placed on a Quartz Tuning Fork (QTF) is presented. Instead of using an external deflection with a cantilever beam for contact detection, an original combination of piezoelectric resonator and thermal probe is employed. Due to a non-contact photothermal excitation principle, the high quality factor of the QTF allows the probe-to-surface contact detection. Topographic and thermal scanning images obtained on a specific sample points out the interest of our system as an alternative to cantilevered resistive probe systems which are the most spread.

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

    Science.gov (United States)

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

    2014-02-01

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

  6. Field-Induced Deformation as a Mechanism for Scanning Tunneling Microscopy Based Nanofabrication

    DEFF Research Database (Denmark)

    Hansen, Ole; Ravnkilde, Jan Tue; Quaade, Ulrich

    1998-01-01

    The voltage between tip and sample in a scanning tunneling microscope (STM) results in a large electric field localized near the tip apex. The mechanical stress due to this field can cause appreciable deformation of both tip and sample on the scale of the tunnel gap. We derive an approximate...

  7. Simultaneous topographic and elemental chemical and magnetic contrast in scanning tunneling microscopy

    Science.gov (United States)

    Rose, Volker; Preissner, Curt A; Hla, Saw-Wai; Wang, Kangkang; Rosenmann, Daniel

    2014-09-30

    A method and system for performing simultaneous topographic and elemental chemical and magnetic contrast analysis in a scanning, tunneling microscope. The method and system also includes nanofabricated coaxial multilayer tips with a nanoscale conducting apex and a programmable in-situ nanomanipulator to fabricate these tips and also to rotate tips controllably.

  8. Scanning tunneling spectroscopy on organic semiconductors : experiment and model

    NARCIS (Netherlands)

    Kemerink, M.; Alvarado, S.F.; Müller, P.; Koenraad, P.M.; Salemink, H.W.M.; Wolter, J.H.; Janssen, R.A.J.

    2004-01-01

    Scanning-tunneling spectroscopy expts. performed on conjugated polymer films are compared with three-dimensional numerical model calcns. for charge injection and transport. It is found that if a sufficiently sharp tip is used, the field enhancement near the tip apex leads to a significant increase

  9. Detection of picosecond electrical transients in a scanning tunneling microscope

    NARCIS (Netherlands)

    Groeneveld, R.H.M.; Rasing, T.H.M.; Kaufmann, L.M.F.; Smalbrugge, E.; Wolter, J.H.; Melloch, M.R.; Kempen, van H.

    1996-01-01

    We have developed a scanning tunneling microscope using an optoelectronic switch which gates the tunneling tip current. The switch is fabricated within several tens of microns from the tip by photolithography and an accurate cleavage method. We demonstrate this approach by detecting picosecond

  10. At the Tipping Point

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, H. S.

    2011-02-28

    There comes a time in every field of science when things suddenly change. While it might not be immediately apparent that things are different, a tipping point has occurred. Biology is now at such a point. The reason is the introduction of high-throughput genomics-based technologies. I am not talking about the consequences of the sequencing of the human genome (and every other genome within reach). The change is due to new technologies that generate an enormous amount of data about the molecular composition of cells. These include proteomics, transcriptional profiling by sequencing, and the ability to globally measure microRNAs and post-translational modifications of proteins. These mountains of digital data can be mapped to a common frame of reference: the organism’s genome. With the new high-throughput technologies, we can generate tens of thousands of data points from each sample. Data are now measured in terabytes and the time necessary to analyze data can now require years. Obviously, we can’t wait to interpret the data fully before the next experiment. In fact, we might never be able to even look at all of it, much less understand it. This volume of data requires sophisticated computational and statistical methods for its analysis and is forcing biologists to approach data interpretation as a collaborative venture.

  11. Tipping the scales.

    Science.gov (United States)

    1998-12-01

    In the US, the October 1998 murder of a physician who performed abortions was an outward manifestation of the insidious battle against legal abortion being waged by radical Christian social conservatives seeking to transform the US democracy into a theocracy. This movement has been documented in a publication entitled, "Tipping the Scales: The Christian Right's Legal Crusade Against Choice" produced as a result of a 4-year investigation conducted by The Center for Reproductive Law and Policy. This publication describes how these fundamentalists have used sophisticated legal, lobbying, and communication strategies to further their goals of challenging the separation of church and state, opposing family planning and sexuality education that is not based solely on abstinence, promoting school prayer, and restricting homosexual rights. The movement has resulted in the introduction of more than 300 anti-abortion bills in states, 50 of which have passed in 23 states. Most Christian fundamentalist groups provide free legal representation to abortion clinic terrorists, and some groups solicit women to bring specious malpractice claims against providers. Sophisticated legal tactics are used by these groups to remove the taint of extremism and mask the danger posed to US constitutional principles being posed by "a well-financed and zealous brand of radical lawyers and their supporters."

  12. Cooperative scans

    NARCIS (Netherlands)

    M. Zukowski (Marcin); P.A. Boncz (Peter); M.L. Kersten (Martin)

    2004-01-01

    textabstractData mining, information retrieval and other application areas exhibit a query load with multiple concurrent queries touching a large fraction of a relation. This leads to individual query plans based on a table scan or large index scan. The implementation of this access path in most

  13. Nonlinear Phenomena in the Single-Mode Dynamics in an AFM Cantilever Beam

    KAUST Repository

    Ruzziconi, Laura; Lenci, Stefano; Younis, Mohammad I.

    2016-01-01

    This study deals with the nonlinear dynamics arising in an atomic force microscope cantilever beam. After analyzing the static behavior, a single degree of freedom Galerkin reduced order model is introduced, which describes the overall scenario

  14. Indium phosphide-based monolithically integrated PIN waveguide photodiode readout for resonant cantilever sensors

    Energy Technology Data Exchange (ETDEWEB)

    Siwak, N. P. [Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland, College Park, Maryland 20742 (United States); Laboratory for the Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740 (United States); Fan, X. Z.; Ghodssi, R. [Department of Electrical and Computer Engineering, Institute for Systems Research, University of Maryland, College Park, Maryland 20742 (United States); Kanakaraju, S.; Richardson, C. J. K. [Laboratory for the Physical Sciences, 8050 Greenmead Drive, College Park, Maryland 20740 (United States)

    2014-10-06

    An integrated photodiode displacement readout scheme for a microelectromechanical cantilever waveguide resonator sensing platform is presented. III-V semiconductors are used to enable the monolithic integration of passive waveguides with active optical components. This work builds upon previously demonstrated results by measuring the displacement of cantilever waveguide resonators with on-chip waveguide PIN photodiodes. The on-chip integration of the readout provides an additional 70% improvement in mass sensitivity compared to off-chip photodetector designs due to measurement stability and minimized coupling loss. In addition to increased measurement stability, reduced packaging complexity is achieved due to the simplicity of the readout design. We have fabricated cantilever waveguides with integrated photodetectors and experimentally characterized these cantilever sensors with monolithically integrated PIN photodiodes.

  15. Fracture strength of fiber-reinforced surface-retained anterior cantilever restorations

    NARCIS (Netherlands)

    Oezcan, Mutlu; Kumbuloglu, Ovul; User, Atilla

    2008-01-01

    Purpose: This study compared the fracture strength of direct anterior cantilever fiber-reinforced composite (FRC) fixed partial dentures (FPD) reinforced with 3 types of E-glass fibers preimpregnated with either urethane tetramethacrylate, bisphenol glycidylmethacrylate/polymethyl methacrylate, or

  16. Computer aided design of Langasite resonant cantilevers: analytical models and simulations

    Science.gov (United States)

    Tellier, C. R.; Leblois, T. G.; Durand, S.

    2010-05-01

    Analytical models for the piezoelectric excitation and for the wet micromachining of resonant cantilevers are proposed. Firstly, computations of metrological performances of micro-resonators allow us to select special cuts and special alignment of the cantilevers. Secondly the self-elaborated simulator TENSOSIM based on the kinematic and tensorial model furnishes etching shapes of cantilevers. As the result the number of selected cuts is reduced. Finally the simulator COMSOL® is used to evaluate the influence of final etching shape on metrological performances and especially on the resonance frequency. Changes in frequency are evaluated and deviating behaviours of structures with less favourable built-ins are tested showing that the X cut is the best cut for LGS resonant cantilevers vibrating in flexural modes (type 1 and type 2) or in torsion mode.

  17. Sensing technology for damage assessment of sign supports and cantilever poles : final report, August 31, 2010.

    Science.gov (United States)

    2010-08-31

    This report presents the results of research activities conducted under Contract No. 519691-PIT 008 on Sensing Technology for : Damage Assessment of Sign Supports and Cantilever Poles between the University of Pittsburgh and the Pennsylvania De...

  18. Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling

    International Nuclear Information System (INIS)

    Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth; Bøggild, Peter; Bartenwerfer, Malte; Krohs, Florian; Oliva, Maria; Harzendorf, Torsten

    2013-01-01

    Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility in terms of defining the shape and size of the tip. Due to beam-induced deformation, it has so far not been possible to define HAR structures using lateral FIB milling. In this work we obtain aspect ratios of up to 45, with tip diameters down to 9 nm, by a deformation-suppressing writing strategy. Several FIB milling strategies for obtaining sharper tips are discussed. Finally, assembly of the HAR tips on a custom-designed probe as well as the first AFM scanning is shown. (paper)

  19. The Correlated Dynamics of Micron-Scale Cantilevers in a Viscous Fluid

    Science.gov (United States)

    Robbins, Brian A.

    A number of microcantilever systems of fundamental importance are explored using theoretical and numerical methods to quantify and provide physical insights into the dynamics of experimentally accessible systems that include a variety of configurations and viscous fluids. It is first shown that the correlated dynamics of both a laterally and vertically offset cantilever pair can be accurately predicted by numerical simulations. This is verified by comparing the correlated dynamics yielded by numerical simulations with experimental measurement. It is also demonstrated that in order to obtain these accurate predictions, geometric details of the cantilever must be included in the numerical simulation to directly reflect the experimental cantilever. A microrheology technique that utilizes the fluctuation-dissipation theorem is proposed. It is shown that by including the frequency dependence of the fluid damping, improvements in accuracy of the predictions of the rheological properties of the surrounding fluid are observed over current techniques. The amplitude spectrum of a 2-D cantilever in a power-law fluid is studied. The resulting amplitude spectrum yielded a curve similar to an overdamped system. It is observed that the amplitude and noise spectrum yield the same qualitative response for a 2-D cantilever in a shear-thinning, power-law fluid. The correlated dynamics of a tethered vertically offset cantilever pair is investigated. It is shown that for a range of stiffness ratios, which is the ratio of the spring constant of the tethering relative to the cantilever spring constant, the change in the correlated dynamics of a Hookean spring tethered cantilever pair can be seen in the presence of fluid coupling. The dynamics of a spring-mass tethered, vertically offset cantilever pair is qualitatively studied by simplifying the model to an array of springs and masses. The resulting study found that the correlated dynamics of the displacement of mass of the tethered

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

    International Nuclear Information System (INIS)

    Shia Xiaolei; Guo Liqiu; Bai Yang; Qiao Lijie

    2011-01-01

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

  1. DESIGN of MICRO CANTILEVER BEAM for VAPOUR DETECTION USING COMSOL MULTI PHYSICS SOFTWARE

    OpenAIRE

    Sivacoumar R; Parvathy JM; Pratishtha Deep

    2015-01-01

    This paper gives an overview of micro cantilever beam of various shapes and materials for vapour detection. The design of micro cantilever beam, analysis and simulation is done for each shape. The simulation is done using COMSOL Multi physics software using structural mechanics and chemical module. The simulation results of applied force and resulting Eigen frequencies will be analyzed for different beam structures. The vapour analysis is done using flow cell that consists of chemical pill...

  2. A closed-loop system for frequency tracking of piezoresistive cantilever sensors

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Zhang, Qing; Merzsch, Stephan; Waag, Andreas; Peiner, Erwin

    2013-05-01

    A closed loop circuit capable of tracking resonant frequencies for MEMS-based piezoresistive cantilever resonators is developed in this work. The proposed closed-loop system is mainly based on a phase locked loop (PLL) circuit. In order to lock onto the resonant frequency of the resonator, an actuation signal generated from a voltage-controlled oscillator (VCO) is locked to the phase of the input reference signal of the cantilever sensor. In addition to the PLL component, an instrumentation amplifier and an active low pass filter (LPF) are connected to the system for gaining the amplitude and reducing the noise of the cantilever output signals. The LPF can transform a rectangular signal into a sinusoidal signal with voltage amplitudes ranging from 5 to 10 V which are sufficient for a piezoactuator input (i.e., maintaining a large output signal of the cantilever sensor). To demonstrate the functionality of the system, a self-sensing silicon cantilever resonator with a built-in piezoresistive Wheatstone bridge is fabricated and integrated with the circuit. A piezoactuator is utilized for actuating the cantilever into resonance. Implementation of this closed loop system is used to track the resonant frequency of a silicon cantilever-based sensor resonating at 9.4 kHz under a cross-sensitivity test of ambient temperature. The changes of the resonant frequency are interpreted using a frequency counter connected to the system. From the experimental results, the temperature sensitivity and coefficient of the employed sensor are 0.3 Hz/°C and 32.8 ppm/°C, respectively. The frequency stability of the system can reach up to 0.08 Hz. The development of this system will enable real-time nanoparticle monitoring systems and provide a miniaturization of the instrumentation modules for cantilever-based nanoparticle detectors.

  3. MEMS-based silicon cantilevers with integrated electrothermal heaters for airborne ultrafine particle sensing

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Merzsch, Stephan; Waag, Andreas; Peiner, Erwin

    2013-05-01

    The development of low-cost and low-power MEMS-based cantilever sensors for possible application in hand-held airborne ultrafine particle monitors is described in this work. The proposed resonant sensors are realized by silicon bulk micromachining technology with electrothermal excitation, piezoresistive frequency readout, and electrostatic particle collection elements integrated and constructed in the same sensor fabrication process step of boron diffusion. Built-in heating resistor and full Wheatstone bridge are set close to the cantilever clamp end for effective excitation and sensing, respectively, of beam deflection. Meanwhile, the particle collection electrode is located at the cantilever free end. A 300 μm-thick, phosphorus-doped silicon bulk wafer is used instead of silicon-on-insulator (SOI) as the starting material for the sensors to reduce the fabrication costs. To etch and release the cantilevers from the substrate, inductively coupled plasma (ICP) cryogenic dry etching is utilized. By controlling the etching parameters (e.g., temperature, oxygen content, and duration), cantilever structures with thicknesses down to 10 - 20 μm are yielded. In the sensor characterization, the heating resistor is heated and generating thermal waves which induce thermal expansion and further cause mechanical bending strain in the out-of-plane direction. A resonant frequency of 114.08 +/- 0.04 kHz and a quality factor of 1302 +/- 267 are measured in air for a fabricated rectangular cantilever (500x100x13.5 μm3). Owing to its low power consumption of a few milliwatts, this electrothermal cantilever is suitable for replacing the current external piezoelectric stack actuator in the next generation of the miniaturized cantilever-based nanoparticle detector (CANTOR).

  4. Use of self-sensing piezoresistive Si cantilever sensor for determining carbon nanoparticle mass

    Science.gov (United States)

    Wasisto, H. S.; Merzsch, S.; Stranz, A.; Waag, A.; Uhde, E.; Kirsch, I.; Salthammer, T.; Peiner, E.

    2011-06-01

    A silicon cantilever with slender geometry based Micro Electro Mechanical System (MEMS) for nanoparticles mass detection is presented in this work. The cantilever is actuated using a piezoactuator at the bottom end of the cantilever supporting frame. The oscillation of the microcantilever is detected by a self-sensing method utilizing an integrated full Wheatstone bridge as a piezoresistive strain gauge for signal read out. Fabricated piezoresistive cantilevers of 1.5 mm long, 30 μm wide and 25 μm thick have been employed. This self-sensing cantilever is used due to its simplicity, portability, high-sensitivity and low-cost batch microfabrication. In order to investigate air pollution sampling, a nanoparticles collection test of the piezoresistive cantilever sensor is performed in a sealed glass chamber with a stable carbon aerosol inside. The function principle of cantilever sensor is based on detecting the resonance frequency shift that is directly induced by an additional carbon nanoparticles mass deposited on it. The deposition of particles is enhanced by an electrostatic field. The frequency measurement is performed off-line under normal atmospheric conditions, before and after carbon nanoparticles sampling. The calculated equivalent mass-induced resonance frequency shift of the experiment is measured to be 11.78 +/- 0.01 ng and a mass sensitivity of 8.33 Hz/ng is obtained. The proposed sensor exhibits an effective mass of 2.63 μg, a resonance frequency of 43.92 kHz, and a quality factor of 1230.68 +/- 78.67. These results and analysis indicate that the proposed self-sensing piezoresistive silicon cantilever can offer the necessary potential for a mobile nanoparticles monitor.

  5. A Novel Approach to the Sensing of Liquid Density Using a Plastic Optical Fibre Cantilever Beam

    Science.gov (United States)

    Kulkarni, Atul; Kim, Youngjin; Kim, Taesung

    2009-01-01

    This article reports for the first time the use of a plastic optical fibre (POF) cantilever beam to measure the density of a liquid. The sensor is based on the Archimedes buoyancy principle. The sensor consists of a POF bonded on the surface of a metal beam in the form of a cantilever configuration, and at the free end of the beam a displacer is…

  6. Fabrication of a cantilever-based microfluidic flow meter with nL min(-1) resolution

    DEFF Research Database (Denmark)

    Noeth, Nadine-Nicole; Keller, Stephan Sylvest; Boisen, Anja

    2011-01-01

    A microfluidic flow meter based on cantilever deflection is developed, showing a resolution down to 3 nL min(-1) for flows in the microliter range. The cantilevers are fabricated in SU-8 and have integrated holes with dimensions from 5 x 5 to20x 20 mu m(2). The holes make it possible to measure i......, hole-to-hole distance, amount of holes, etc) the sensitivity of the sensor can be changed....

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-15

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

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

    Science.gov (United States)

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

    2014-04-01

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

  10. Radionuclide scanning

    International Nuclear Information System (INIS)

    Shapiro, B.

    1986-01-01

    Radionuclide scanning is the production of images of normal and diseased tissues and organs by means of the gamma-ray emissions from radiopharmaceutical agents having specific distributions in the body. The gamma rays are detected at the body surface by a variety of instruments that convert the invisible rays into visible patterns representing the distribution of the radionuclide in the body. The patterns, or images, obtained can be interpreted to provide or to aid diagnoses, to follow the course of disease, and to monitor the management of various illnesses. Scanning is a sensitive technique, but its specificity may be low when interpreted alone. To be used most successfully, radionuclide scanning must be interpreted in conjunction with other techniques, such as bone radiographs with bone scans, chest radiographs with lung scans, and ultrasonic studies with thyroid scans. Interpretation is also enhanced by providing pertinent clinical information because the distribution of radiopharmaceutical agents can be altered by drugs and by various procedures besides physiologic and pathologic conditions. Discussion of the patient with the radionuclide scanning specialist prior to the study and review of the results with that specialist after the study are beneficial

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-06-15

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

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

    International Nuclear Information System (INIS)

    Prunici, Pavel; Hess, Peter

    2008-01-01

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

  13. Innovative multi-cantilever array sensor system with MOEMS read-out

    Science.gov (United States)

    Ivaldi, F.; Bieniek, T.; Janus, P.; Grabiec, P.; Majstrzyk, W.; Kopiec, D.; Gotszalk, T.

    2016-11-01

    Cantilever based sensor system are a well-established sensor family exploited in several every-day life applications as well as in high-end research areas. The very high sensitivity of such systems and the possibility to design and functionalize the cantilevers to create purpose built and highly selective sensors have increased the interest of the scientific community and the industry in further exploiting this promising sensors type. Optical deflection detection systems for cantilever sensors provide a reliable, flexible method for reading information from cantilevers with the highest sensitivity. However the need of using multi-cantilever arrays in several fields of application such as medicine, biology or safety related areas, make the optical method less suitable due to its structural complexity. Working in the frame of a the Joint Undertaking project Lab4MEMS II our group proposes a novel and innovative approach to solve this issue, by integrating a Micro-Opto-Electro-Mechanical-System (MOEMS) with dedicated optics, electronics and software with a MOEMS micro-mirror, ultimately developed in the frame of Lab4MEMSII. In this way we are able to present a closely packed, lightweight solution combining the advantages of standard optical read-out systems with the possibility of recording multiple read-outs from large cantilever arrays quasi simultaneously.

  14. Electrothermal piezoresistive cantilever resonators for personal measurements of nanoparticles in workplace exposure

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Wu, Wenze; Uhde, Erik; Waag, Andreas; Peiner, Erwin

    2015-05-01

    Low-cost and low-power piezoresistive cantilever resonators with integrated electrothermal heaters are developed to support the sensing module enhancement of the second generation of handheld cantilever-based airborne nanoparticle (NP) detector (CANTOR-2). These sensors are used for direct-reading of exposure to carbon engineered nanoparticles (ENPs) at indoor workplaces. The cantilever structures having various shapes of free ends are created using silicon bulk micromachining technologies (i.e, rectangular, hammer-head, triangular, and U-shaped cantilevers). For a complete wearable CANTOR-2, all components of the proposed detector can be grouped into two main units depending on their packaging placements (i.e., the NP sampler head and the electronics mounted in a handy-format housing). In the NP sampler head, a miniaturized electrophoretic aerosol sampler and a resonant silicon cantilever mass sensor are employed to collect the ENPs from the air stream to the cantilever surfaces and measuring their mass concentration, respectively. After calibration, the detected ENP mass concentrations of CANTOR-2 show a standard deviation from fast mobility particle sizer (FMPS, TSI 3091) of 8-14%.

  15. Determining the thermal expansion coefficient of thin films for a CMOS MEMS process using test cantilevers

    International Nuclear Information System (INIS)

    Cheng, Chao-Lin; Fang, Weileun; Tsai, Ming-Han

    2015-01-01

    Many standard CMOS processes, provided by existing foundries, are available. These standard CMOS processes, with stacking of various metal and dielectric layers, have been extensively applied in integrated circuits as well as micro-electromechanical systems (MEMS). It is of importance to determine the material properties of the metal and dielectric films to predict the performance and reliability of micro devices. This study employs an existing approach to determine the coefficients of thermal expansion (CTEs) of metal and dielectric films for standard CMOS processes. Test cantilevers with different stacking of metal and dielectric layers for standard CMOS processes have been designed and implemented. The CTEs of standard CMOS films can be determined from measurements of the out-of-plane thermal deformations of the test cantilevers. To demonstrate the feasibility of the present approach, thin films prepared by the Taiwan Semiconductor Manufacture Company 0.35 μm 2P4M CMOS process are characterized. Eight test cantilevers with different stacking of CMOS layers and an auxiliary Si cantilever on a SOI wafer are fabricated. The equivalent elastic moduli and CTEs of the CMOS thin films including the metal and dielectric layers are determined, respectively, from the resonant frequency and static thermal deformation of the test cantilevers. Moreover, thermal deformations of cantilevers with stacked layers different to those of the test beams have been employed to verify the measured CTEs and elastic moduli. (paper)

  16. Three-electrode self-actuating self-sensing quartz cantilever: design, analysis, and experimental verification.

    Science.gov (United States)

    Chen, C Julian; Schwarz, Alex; Wiesendanger, Roland; Horn, Oliver; Müller, Jörg

    2010-05-01

    We present a novel quartz cantilever for frequency-modulation atomic force microscopy (FM-AFM) which has three electrodes: an actuating electrode, a sensing electrode, and a ground electrode. By applying an ac signal on the actuating electrode, the cantilever is set to vibrate. If the frequency of actuation voltage closely matches one of the characteristic frequencies of the cantilever, a sharp resonance should be observed. The vibration of the cantilever in turn generates a current on the sensing electrode. The arrangement of the electrodes is such that the cross-talk capacitance between the actuating electrode and the sensing electrode is less than 10(-16) F, thus the direct coupling is negligible. To verify the principle, a number of samples were made. Direct measurements with a Nanosurf easyPPL controller and detector showed that for each cantilever, one or more vibrational modes can be excited and detected. Using classical theory of elasticity, it is shown that such novel cantilevers with proper dimensions can provide optimized performance and sensitivity in FM-AFM with very simple electronics.

  17. Design and Fabrication of Piezoresistive Based Encapsulated Poly-Si Cantilevers for Bio/chemical Sensing

    Science.gov (United States)

    Krishna, N. P. Vamsi; Murthy, T. R. Srinivasa; Reddy, K. Jayaprakash; Sangeeth, K.; Hegde, G. M.

    Cantilever-based sensing is a growing research field not only within micro regime but also in nano technology. The technology offers a method for rapid, on-line and in-situ monitoring of specific bio/chemical substances by detecting the nanomechanical responses of a cantilever sensor. Cantilever with piezoresistive based detection scheme is more attractive because of its electronics compatibility. Majority of commercially available micromachined piezoresistive sensors are bulk micromachined devices and are fabricated using single crystal silicon wafers. As substrate properties are not important in surface micromachining, the expensive silicon wafers can be replaced by cheaper substrates, such as poly-silicon, glass or plastic. Here we have designed SU-8 based bio/chemical compatible micro electro mechanical device that includes an encapsulated polysilicon piezoresistor for bio/chemical sensing. In this paper we report the design, fabrication and analysis of the encapsulated poly-Si cantilevers. Design and theoretical analysis are carried out using Finite Element Analysis software. For fabrication of poly-silicon piezoresistive cantilevers we followed the surface micromachining process steps. Preliminary characterization of the cantilevers is presented.

  18. Cancelation of thermally induced frequency shifts in bimaterial cantilevers by nonlinear optomechanical interactions

    Energy Technology Data Exchange (ETDEWEB)

    Vy, Nguyen Duy, E-mail: nguyenduyvy@tdt.edu.vn [Theoretical Physics Research Group, Ton Duc Thang University, Ho Chi Minh City 756636 (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City 756636 (Viet Nam); Tri Dat, Le [Faculty of Physics and Engineering Physics, University of Science, Ho Chi Minh City 748355 (Viet Nam); Iida, Takuya [Department of Physical Science, Osaka Prefecture University, 1-1 Gakuen-cho, Nakaku, Sakai, Osaka 599-8531 (Japan)

    2016-08-01

    Bimaterial cantilevers have recently been used in, for example, the calorimetric analysis with picowatt resolution in microscopic space based on state-of-the-art atomic force microscopes. However, thermally induced effects usually change physical properties of the cantilevers, such as the resonance frequency, which reduce the accuracy of the measurements. Here, we propose an approach to circumvent this problem that uses an optical microcavity formed between a metallic layer coated on the back of the cantilever and one coated at the end of an optical fiber irradiating the cantilever. In addition to increasing the sensitivity, the optical rigidity of this system diminishes the thermally induced frequency shift. For a coating thickness of several tens of nanometers, the input power is 5–10 μW. These values can be evaluated from parameters derived by directly irradiating the cantilever in the absence of the microcavity. The system has the potential of using the cantilever both as a thermometer without frequency shifting and as a sensor with nanometer-controlled accuracy.

  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... echoes from the tissues in the body. The principles are similar to sonar used by boats and ... bleeding resistant to traditional medical treatments. The greatest difference in performing TIPS in children is their tremendous ...

  20. Fitness: Tips for Staying Motivated

    Science.gov (United States)

    Healthy Lifestyle Fitness Fitness is for life. Motivate yourself with these practical tips. By Mayo Clinic Staff Have ... 27, 2015 Original article: http://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/fitness/art-20047624 . Mayo Clinic ...

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    Full Text Available ... deeply you are sedated. When the needle is advanced through the liver and the pathway is expanded ... are the limitations of TIPS? Patients with more advanced liver disease are at greater risk for worsening ...

  2. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... to determine the severity of the condition. To help plan for the placement of the TIPS stent, ... Radiological Society of North America, Inc. (RSNA). To help ensure current and accurate information, we do not ...

  3. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... avoiding the liver. TIPS may successfully reduce internal bleeding in the stomach and esophagus in patients with ... stomach, lower esophagus, and intestines, causing enlarged vessels, bleeding and the accumulation of fluid in the chest ...

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... in the chest or abdomen. This condition is most commonly seen in adults, often as a result ... minimally invasive procedures such as a TIPS are most often performed by a specially trained interventional radiologist ...

  5. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... open. Patients who typically need a TIPS have portal hypertension , meaning they have increased pressure in the portal ... problems leading to cirrhosis (scarring of the liver). Portal hypertension can also occur in children, although children are ...

  6. Energy Savers: Cool Summer Tips

    International Nuclear Information System (INIS)

    Miller, M.

    2001-01-01

    A tri-fold brochure addressing energy-saving tips for homeowners ranging from low- or no-cost suggestions to higher cost suggestions for longer-term savings. Cooling, windows, weatherizing, and landscaping are addressed

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... complex and lengthy procedures requiring extended fluoroscopy use) death (rare) top of page What are the limitations ... filtered out by the liver. The TIPS may cause too much of these substances to bypass the ...

  8. Girlfriends' Health and Safety Tips

    Science.gov (United States)

    ... in Women? Women's Safety and Health Issues at Work Health Equity Girlfriends' Health and Safety Tips Recommend on Facebook Tweet Share Compartir Having friends is an important part of life. Celebrate female friendship and support your girlfriends by ...

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  10. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... you are pregnant and discuss any recent illnesses, medical conditions, allergies and medications you’re taking. You ... with ascites or variceal bleeding resistant to traditional medical treatments. The greatest difference in performing TIPS in ...

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient Center This ... To locate a medical imaging or radiation oncology provider in your community, you can search the ACR- ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... surgery. Your TIPS should have less of an effect than open surgical bypass on future liver transplantation ... Encephalopathy can be treated with certain medications, a special diet or, by revising the stent, but sometimes ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in ... limitations of TIPS? Patients with more advanced liver disease are at greater risk for worsening liver failure ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... is completed. top of page What are the benefits vs. risks? Benefits A TIPS is designed to produce the same ... risk of infection. The chance of infection requiring antibiotic treatment appears to be less than one in ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... hepatic vein to identify the portal venous system. Access is then gained from the hepatic vein into ... TIPS procedure to make sure that it remains open and functions properly. top of page Who interprets ...

  17. Tips to Prevent Mosquito Bites

    Science.gov (United States)

    ... discourage mosquitoes, ticks and other biting insects from landing on you. Here are tips for other preventive ... CDC Mosquito Control Methods - NPIC Exit Top of Page Contact Us to ask a question, provide feedback, ...

  18. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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  19. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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  20. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient Center This ... here Images × Image Gallery Radiologist and patient consultation. View full size with caption Pediatric Content Some imaging ...

  1. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... bear denotes child-specific content. Related Articles and Media Radiation Dose in X-Ray and CT Exams Contrast Materials Venography Images related to Transjugular Intrahepatic Portosystemic Shunt (TIPS) Sponsored ...

  2. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... story about radiology? Share your patient story here Images × Image Gallery Radiologist and patient consultation. View full size ... X-Ray and CT Exams Contrast Materials Venography Images related to Transjugular Intrahepatic Portosystemic Shunt (TIPS) Sponsored ...

  3. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... observed. This procedure is usually completed in an hour or two but may take up to several ...

  4. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... the portal system using a TIPS needle (a special long needle extending from the neck into the ... Encephalopathy can be treated with certain medications, a special diet or, by revising the stent, but sometimes ...

  5. (Allium cepa) root tip mitosis

    African Journals Online (AJOL)

    Aghomotsegin

    their chemical composition and genotoxic effects on cell reproduction. Two petrochemicals, air ... the chromosomes of the individual cells of the root tip could be a pointer to their ..... Chromosome technique: Theory and. Practice. Butterworths ...

  6. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... Intrahepatic Portosystemic Shunt (TIPS)? What are some common uses of the procedure? How should I prepare? What does the equipment look like? How does the procedure work? How is the procedure performed? What will I ...

  7. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... in creating the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient ... Send us your feedback Did you find the information you were looking for? Yes No Please type ...

  8. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... of bleeding that can occur can sometimes be life threatening and those patients are monitored in intensive ...

  9. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... blood draining from the bowel back to the heart while avoiding the liver. TIPS may successfully reduce ... blood away from the liver back to the heart). A stent is then placed in this tunnel ...

  10. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... portal vein to the hepatic vein in the liver. A small metal device called a stent is ... bowel back to the heart while avoiding the liver. TIPS may successfully reduce internal bleeding in the ...

  11. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... have special pediatric considerations. The teddy bear denotes child-specific content. Related Articles and Media Radiation Dose ...

  12. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... the liver. A small metal device called a stent is placed to keep the connection open and ... a small, tubular metal device commonly called a stent . During a TIPS procedure, interventional radiologists use image ...

  13. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... who typically need a TIPS have portal hypertension , meaning they have increased pressure in the portal vein ... the local anesthetic is injected. Most of the sensation is at the skin incision site, which is ...

  14. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... physician will numb an area just above your right collarbone with a local anesthetic . A very small ...

  15. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... top of page What are the benefits vs. risks? Benefits A TIPS is designed to produce the ... skin that does not have to be stitched. Risks Any procedure where the skin is penetrated carries ...

  16. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... Patients who typically need a TIPS have portal hypertension , meaning they have increased pressure in the portal ... leading to cirrhosis (scarring of the liver). Portal hypertension can also occur in children, although children are ...

  17. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... pressure. top of page How does the procedure work? A TIPS reroutes blood flow in the liver ... above your collarbone, and guide a catheter, a long, thin, hollow plastic tube into the vessel. Using ...

  18. Transjugular Intrahepatic Portosystemic Shunt (TIPS)

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    Full Text Available ... This can result in significant challenges in creating the TIPS. top of page Additional Information and Resources Society of Interventional Radiology (SIR) - Patient Center This page ...

  19. Large eddy simulation of turbulent flow for wall mounted cantilever cylinders of aspect ratio 6 and 10

    International Nuclear Information System (INIS)

    Afgan, Imran; Moulinec, Charles; Prosser, Robert; Laurence, Dominique

    2007-01-01

    The flow structure around wall mounted circular cylinders of finite heights is numerically investigated via large eddy simulation (LES). The cylinder aspect ratios (AR) are 6 and 10 and the Reynolds number (Re) based on cylinder diameter and free stream velocity is 20,000 for both cases. The cantilever cylinder mounted on a flat plate is chosen since it gives insight into two entirely different flow phenomena; the tip effects of the free end (which show strong three-dimensional wake structures) and the base or junction effects (due to interaction of flow between the cylinder and the flat plate). Regular vortex shedding is found in the wake of the higher aspect ratio case as was anticipated, along with a strong downwash originating from the flow over the free end of the cylinder, whereas irregular and intermittent vortex shedding occurs in the lower aspect ratio case. Pressure distributions are computed along the length of the cylinder and compared to experimental results. Lift and drag values are also computed, along with Strouhal numbers

  20. Tip model of cold fission

    International Nuclear Information System (INIS)

    Goennenwein, F.; Boersig, B.

    1991-01-01

    Cold fission is defined to be the limiting case of nuclear fission where virtually all of the available energy is converted into the total kinetic energy of the fragments. The fragments have, therefore, to be born in or at least close to their respective ground states. Starting from the viewpoint that cold fission corresponds to most compact scission configurations, energy constraints have been exploited to calculate minimum tip distances between the two nascent fragments in binary fission. Crucial input parameters to this tip model of cold fission are the ground-state deformations of fragment nuclei. It is shown that the minimum tip distances being compatible with energy conservation vary strongly with both the mass and charge fragmentation of the fission prone nucleus. The tip distances refer to nuclei with equivalent sharp surfaces. In keeping with the size of the surface width of leptodermous nuclei, only configurations where the tip distances are smaller than a few fm may be considered as valid scission configurations. From a comparison with experimental data on cold fission this critical tip distance appears to be 3.0 fm for the model parameters chosen. Whenever the model calculation yields tip distances being smaller than the critical value, a necessary condition for attaining cold fission is considered to be fulfilled. It is shown that this criterion allows to understand in fair agreement with experiment which mass fragmentations are susceptible to lead to cold fission and which fragment-charge divisions are the most favored in each isobaric mass chain. Being based merely on energy arguments, the model cannot aim at predicting fragment yields in cold fission. However, the tip model proposed appears well suited to delineate the phase space where cold fission phenomena may come into sight. (orig.)