The Experts below are selected from a list of 35517 Experts worldwide ranked by ideXlab platform

Yuki Shimizu - One of the best experts on this subject based on the ideXlab platform.

  • feasibility study on the concept of thermal Contact Sensor for nanometre level defect inspections on smooth surfaces
    Measurement Science and Technology, 2014
    Co-Authors: Yuki Shimizu, Wenjian Lu, Yuta Ohba
    Abstract:

    This paper presents a feasibility study on the concept of a thermal Contact Sensor that detects nanometre-scale defects on smoothly finished surfaces such as bare silicon wafers, magnetic disks and so on. The Contact Sensor has a thermal element, which is composed of thin-film structures with a thermally sensitive area of several tens of ?m2 on its tip surface. In the proposed concept, the thermal element detects the existence of asperity-type defects on smooth surfaces by capturing frictional heats due to slight Contacts between the thermal element surface and defects. During the defect detection, a gap between the thermal element surface and the smooth surface being rotated by a precision spindle would be maintained. By monitoring deviation of the electrical resistance of the thermal element while scanning the Contact Sensor across the rotating surface, defects on the target surface can be detected. In this paper, a fabrication process for the thermal element has been designed based on the photolithography process, and the first prototype of the thermal element has been fabricated. Results of laser exposure tests have revealed that the fabricated thermal element can detect a rate of heat supply of 10??W, which is the same order as the rate of heat supply assumed to be generated at defect detection by the Contact Sensor. In addition, results of Contact detection tests have confirmed the feasibility of the fabricated thermal element as a Contact detection Sensor.

  • Pit detection using a Contact Sensor
    IEEE Transactions on Magnetics, 2013
    Co-Authors: Yuki Shimizu, Jin Liu, Toshiya Shiramatsu, Masaru Furukawa, Hidekazu Kohira
    Abstract:

    Pit detection study of a thermal Contact Sensor was carried out by both experiments and simulation. The experimental results showed that the thermal Contact Sensor was able to detect a small pit with fairly good sensitivity. And the simulation study revealed that the mechanism of pit detection is due to worse cooling, which results in higher Sensor temperature, because the Sensor/disk spacing is larger on the pit compared with at nominal flying state. And the temperature increase of Sensor can be attributed to worse heat flux due to both larger spacing and air-bearing pressure drop when the Sensor is above the pit.

  • Design and Experiment of Thermal Contact Sensor Detecting Defects on Si Wafer Surface
    Key Engineering Materials, 2012
    Co-Authors: Yuki Shimizu, So Ito, Wei Gao
    Abstract:

    A deign study of a thermal-type Contact Sensor for the detection of small defects, the heights of which are less than 16 nm on the wafer surface, is described in this paper. The feasibility of the Contact Sensor, which would detect frictional heat generated at the Contact with defects, was theoretically investigated focusing on the temperature rise of the Sensor element. To investigate the temperature rise of the Contact Sensor due to the generated frictional heat, both the theoretical calculation with simple model of heat transfer and a simulation with a finite element model (FEM) was carried out. Relationship between the Sensor size and the response of the temperature rise of the Contact Sensor was also investigated by using FEM simulation.

  • New Measurement Concept of Nanometer-Level Defects on Si Wafer Surface by Using Micro Contact Sensor
    Advanced Materials Research, 2012
    Co-Authors: Yuki Shimizu, Wei Gao
    Abstract:

    A thermal-type Contact Sensor was proposed to detect small defects, the heights of which are less than 16 nm, on the wafer surface. The feasibility of the Contact Sensor, which detects frictional heat generated at the Contact, was theoretically investigated focusing on the temperature rise of the Sensor element. Simulation results with both the simple model of heat transfer and the FEM model showed that the expected temperature rise of the Contact Sensor is enough to be detected by the conventional electric circuit.

  • Nano-Scale Defect Mapping on a Magnetic Disk Surface Using a Contact Sensor
    IEEE Transactions on Magnetics, 2011
    Co-Authors: Yuki Shimizu, Toshiya Shiramatsu, Hidekazu Kohira, Masayuki Kurita, Masaru Furukawa
    Abstract:

    Targeting both higher touchdown sensitivity and highly accurate nanometer-scale defect detection on a disk surface, a thermal-Contact Sensor, integrated into a magnetic-head slider, was developed. It was experimentally shown that the Contact Sensor has sensitivity for detecting head-disk Contact at each radial position on a disk surface equivalent to that of a conventional acoustic-emission (AE) Sensor. It was also shown that a defect-detection method using the thermal-Contact Sensor is feasible. Defect mapping, in which a slider inspecting the disk at a certain clearance detects small defects on the disk surface, done with this method was better sensitive with measurements with an optical surface analyzer (OSA). Defect mapping on a proto-type glide tester, based on a conventional glide tester, using the thermal-Contact Sensor was also demonstrated.

Le Gu - One of the best experts on this subject based on the ideXlab platform.

  • the effect of a thermal Contact Sensor on the temperature distribution and heat flux at the disk surface
    Tribology International, 2019
    Co-Authors: Chuanwei Zhang, Dezhi Zheng, Liqin Wang, Le Gu
    Abstract:

    Abstract The thermal response of the head-disk interface due to the presence of a thermal Contact Sensor is investigated. The temperature distribution near the Contact Sensor is calculated considering changes in the temperature of disk surface. The heat transfer in the air bearing near the Contact Sensor is determined. The results show that the Contact Sensor causes a high temperature of the disk surface, which is mainly generated by the conductive heat transfer. The increased disk temperature reduces the heat flux leaving the slider, which, in turn, causes an increased temperature of the Contact Sensor.

Hassan Y. Aboul-enein - One of the best experts on this subject based on the ideXlab platform.

  • Quantitative analysis of methacycline hydrochloride by direct potentiometry using the internal solid Contact Sensor.
    Analytical sciences : the international journal of the Japan Society for Analytical Chemistry, 2007
    Co-Authors: Xian Xiang Sun, Hassan Y. Aboul-enein
    Abstract:

    An internal solid Contact Sensor (ISCS) for the determination of methacycline hydrochloride (MC·Cl), Pt/PPy/PVC(MC-PT), is described, based on the use of conducting poly(pyrrole) (PPy) as solid Contact material and MC-phosphotungstate (PT) as the ion exchanger and dibutyl phthalate (DBP) as the plasticizer. A direct potentiometric method for the quantitative analysis of MC·Cl is also described. Under the condition of pH 2.7, the linear concentration range, slope (25°C) and detection limit of the Sensor are 6.4 × 1.0-6 - 3.0 × 1.0-3 M, 52.4 ± 0.2 mV/decade and 4.4 × 1.0-6 M, respectively. The response time is

  • Internal solid Contact Sensor for the determination of doxycycline hydrochloride in pharmaceutical formulation
    Talanta, 2002
    Co-Authors: Xian Xiang Sun, Hassan Y. Aboul-enein
    Abstract:

    Abstract The internal solid Contact Sensor for the determination of doxycycline hydrochloride (DC) was developed based on a conducting polypyrrole (PPy) film immobilized on a glassy carbon electrode surface casted by a plasticized polyvinyl chloride (PVC) membrane containing an ion-pair compound of DC with tetraphenylborate (TPB) and dibutylphthalate (DBP) as plasticizer. Effects of various factors for the electropolymerization of pyrrole or aniline, including monomer concentration, acidity or inorganic salt and thickness of polymer film were investigated experimentally. It was found that the slope and the linear range of SCSs changed with both the different concentration of monomer and of KCl in electrolyte solution and with the different substrate material and a marked influence of the change of solution pH on the potential response of Sensor occurred when sample solution pH>3.5. Under the condition of pH 2.8, the Sensor showed a near-Nernstian response over the range of DC concentration of 1.0×10−2–1.0×10−5 mol l−1 with the slope (at 25 °C) of 54.4 mV per decade. The detection limit obtained was 4.0×10−6 mol l−1.The Sensor was successfully applied to determination of DC in pharmaceutical formulation.

V S Letokhov - One of the best experts on this subject based on the ideXlab platform.

  • tuning fork based fast highly sensitive surface Contact Sensor for atomic force microscopy near field scanning optical microscopy
    Review of Scientific Instruments, 2002
    Co-Authors: D V Serebryakov, A P Cherkun, B A Loginov, V S Letokhov
    Abstract:

    We have developed a surface-Contact Sensor on the basis of a tuning fork which differs from the previously described ones in that it has a high operating speed (up to 100 times as fast as the so-called Q limit), requires no external piezoelectric drive, has a sufficiently high sensitivity, and features a “soft” probe attachment which makes the lifetime of the probe equal to that of the standard atomic force microscopy. When using a “soft” probe with a rigidity of 0.5 N/m, one can reliably detect probe tip-to-sample distance variations as small as 0.1 nm. The resonance frequency resolution attained amounted to 2×10−3 Hz. The rate of transient rise is τ=1.5 ms (this refers to the response time of the Sensor proper with the Z-coordinate feedback loop open and not to the response time of the microscope as a whole). We have theoretically substantiated the fact that the Q limit, where Q∼10 000 is the Q factor of the tuning fork proper, is not a fundamental restriction on the operating speed of the Sensor. This ...

  • Tuning-fork-based fast highly sensitive surface-Contact Sensor for atomic force microscopy/near-field scanning optical microscopy
    Review of Scientific Instruments, 2002
    Co-Authors: D V Serebryakov, A P Cherkun, B A Loginov, V S Letokhov
    Abstract:

    We have developed a surface-Contact Sensor on the basis of a tuning fork which differs from the previously described ones in that it has a high operating speed (up to 100 times as fast as the so-called Q limit), requires no external piezoelectric drive, has a sufficiently high sensitivity, and features a “soft” probe attachment which makes the lifetime of the probe equal to that of the standard atomic force microscopy. When using a “soft” probe with a rigidity of 0.5 N/m, one can reliably detect probe tip-to-sample distance variations as small as 0.1 nm. The resonance frequency resolution attained amounted to 2×10−3 Hz. The rate of transient rise is τ=1.5 ms (this refers to the response time of the Sensor proper with the Z-coordinate feedback loop open and not to the response time of the microscope as a whole). We have theoretically substantiated the fact that the Q limit, where Q∼10 000 is the Q factor of the tuning fork proper, is not a fundamental restriction on the operating speed of the Sensor. This ...

Robert D. Howe - One of the best experts on this subject based on the ideXlab platform.

  • Modeling the Effects of Contact Sensor Resolution on Grasp Success
    IEEE Robotics and Automation Letters, 2018
    Co-Authors: Qian Wan, Robert D. Howe
    Abstract:

    This letter presents a quantitative method for analyzing the effect of Sensor resolution on grasp stability prediction. Resolution limits for Contact Sensors are expressed as a range of Contact locations and Contact surface normals that cannot be disambiguated by the Sensor. Grasp quality is assessed at the limits of this range to determine whether the uncertainties caused by Sensor resolution lead to uncertainty in grasp outcome prediction. The analysis also enables calculation of the specific Contact locations on an object where the tactile Sensors are trustworthy and where the object is reliably graspable. Our approach lays the foundation for quantitative evaluation in design tradeoffs in Sensor choices and Sensor layout, as well as finger shapes and materials.

  • Comparison of Contact Sensor localization abilities during manipulation
    Robotics and Autonomous Systems, 1996
    Co-Authors: Jae S. Son, Mark R. Cutkosky, Robert D. Howe
    Abstract:

    This paper presents an experimental comparison of tactile array versus force-torque sensing for localizing Contact during manipulation. The manipulation tasks involved rotating objects and translating objects using a planar two fingered manipulator. A pin and a box were selected as limiting cases of point and line Contact against a cylindrical robot finger tip. Practical implementations of the two Sensor types are compared theoretically and experimentally, and three different localization algorithms for the tactile array Sensor are considered. Force-torque Contact sensing results suffered from difficulties in calibration, transient forces, and low grasp force. Tactile array sensing was immune to these problems and the effect of shear loading was only noticeable for a simple centroid algorithm. The results show that with care, both of these sensing schemes can determine the Contact location within a millimeter during real manipulation tasks.