Download or read book Micro Thin Film Sensor Embedded in Metal Structures for In Situ Process Monitoring During Ultrasonic Welding written by Xudong Cheng and published by . This book was released on 2000 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book SME Technical Paper written by Society of Manufacturing Engineers and published by . This book was released on 2005 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Manufacturing Engineering and Materials Handling 2005 written by and published by . This book was released on 2005 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Study on Metal Embedded Thin Film Micro nano Photonic and Electronic Sensors written by Xugang Zhang and published by . This book was released on 2008 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sensors for In Situ Process Monitoring and Process Control written by and published by . This book was released on 1996 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents the results of the development of an ultrasonic sensor for in-situ monitoring of silicon wafer temperature. The sensor is based on the measurement of the velocity of ultrasonic Lamb waves in the wafer, and relating this velocity to temperature. We present a method for efficient excitation and detection of Lamb waves in the wafer, a theoretical model for relating the variation of velocity as a function of temperature, and an electronic implementation for the sensor. Our results indicate the ability to measure the temperature with an accuracy of 10C in most integrated circuit processing environments. The sensor has also been used in a tomographic configuration to allow the measurement of spatial distribution of temperature. Finally, we highlight the potential for simultaneous measurement of temperature and film thickness in-situ.

Download or read book Chemical Abstracts written by and published by . This book was released on 2002 with total page 2540 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Structurally Compatible Embedded Sensors for Damage Detection in Glass Fibre Reinforced Polymers written by Christina Buggisch and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fibre reinforced polymers exhibit a complex failure behaviour due to their multi-scale nature. Even damage that severely influences the material integrity can often not be detected by visual inspection. Therefore, different non-destructive testing and structural health monitoring (SHM) techniques have been developed to ensure composite structures' reliable and safe operation. Many SHM methods require skilled personnel, expensive measuring equipment and complex sensor networks that reduce the lightweight potential. Especially in carbon fibre reinforced polymers, electrical resistance measurements overcome the limitations. In conductive carbon fibre reinforced polymers, in-situ electrical resistance measurements can monitor the material state during operation without additional sensor networks. However, in unmodified glass fibre reinforced polymers (GFRPs), such resistive monitoring is not possible due to a lack of material conductivity. This dissertation provides two approaches to enable electrical SHM in GFRPs without significantly reducing the mechanical properties. The first method describes a local matrix modification with conductive, fully-integrated, pre-cured single-walled carbon nanotube (SWCNT)/epoxy thin-film sensors. The second technique outlines a local replacement of glass fibre bundles with electrically conductive fibres as conductors for capacitance measurements. The embedded SWCNT/epoxy thin-film sensors exhibit a piezoresistive effect and enable real-time, local strain monitoring. In general, tensile stresses result in a resistance increase and compressive stresses in a resistance decrease. The integrated thin-film sensors do not significantly reduce the mechanical properties for various lay-ups and load cases. Local stress concentrations due to cracks or around holes result in significant resistance increases. The sensitivity of the sensor films can be tuned by geometry variation. First durability studies prove the integrity of the sensors during cyclic fatigue tests. Buckling of a stringer component can be reliably detected during crippling tests by a resistance increase. Capacitance measurements on integrated carbon fibre bundles enable damage detection in GFRP composites due to damage-induced material permittivity changes. Developing damages with incorporated air cause an overall lower permittivity and, thus, a drop in capacitance. Matrix crack evolution and capacitance decrease clearly correlate during tensile tests. The capacitance decreases more severely during rapid crack formation and slower the closer to crack saturation. Analytical modelling of the capacitance decrease is possible with assumptions of an ideal plate capacitor. A higher distance of the bundles decreases the sensitivity towards the end of the test, where a more diffuse crack pattern is present. By integrating the bundles in different layers, crack evolution in the respective layers can precisely be monitored. Furthermore, using the measured capacitance decrease, a detection and size estimation of impact damages is possible. The two presented methods offer highly tailored SHM of GFRPs and can easily be incorporated in industrial processes - carbon fibre bundles can be integrated directly during fabric manufacturing, and pre-cured thin-film sensors can be placed in the desired locations during stacking of dry fabrics. Both methods provide cost-efficient, real-time SHM without significantly altering the material properties and therefore help to enable safer use of GFRP structures.

Download or read book Metals Abstracts written by and published by . This book was released on 1999-04 with total page 972 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book STUDY OF INTEGRATED SEMICONDUC written by Bin Li and published by Open Dissertation Press. This book was released on 2017-01-27 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "A study of integrated semiconductor thin-film sensors on sio2/si substrate" by Bin, Li, 李斌, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled A STUDY OF INTERGATED SEMICONDUCTOR THIN-FILM SENSORS ON SiO /Si SUBSTRATE submitted by Bin Li for the degree of Doctor of Philosophy at the University of Hong Kong in April 2001 With the development of the information technology, the need for miniaturized, intelligent and programmable sensors is rapidly increasing. To meet this trend, developing thin-film sensors on silicon substrate is of great importance. In this thesis, two areas are focused on. One is spreading-resistance temperature (SRT) sensor on silicon on insulator (SOI), while the other is the multi-function thin-film microsensor on SiO /Si substrate. Based on the principle of minority-carrier exclusion effect, SRT sensor on bulk Si is intensively studied. Optimizations of structural parameters and processing conditions on thermal characteristics of SRT sensors are carried out. With appropriately small electrode and high substrate doping, bulk SRT sensor can function at temperatures up to 400 C at a low current of 2 mA. ii SRT sensor on SOI is then investigated with emphasis on its resistance versus temperature (R-T), low-temperature and AC characteristics. Moreover, the effect of Si- film thickness on the maximum operating temperature (T ) is simulated and verified by max experiment results. When the silicon film is sufficiently thin, i.e. 0.1 μm, T can be max significantly raised up to 550 C, even at a very low bias current of 1 μA. Measurements under low-temperature or AC condition reveal that SRT sensor behaves like a conventional resistor. A new microsensor consisting of a thin-film resistor and a metal-insulator- semiconductor (MIS) capacitor is developed by depositing perovskite-type thin film on SiO /Si substrate. SrNb Ti O, Ba La TiO and Ba La Nb Ti O chosen as the 2 x 1-x 3 1-x x 3 1-x x y 1-y 3 sensing film present reasonable multi-function sensitivities to light, heat and humidity. Differences in the sensing properties of the films are related to their chemical compositions and grain boundaries. It is hoped that by varying the chemical composition, processing conditions of the film, better performance could be obtained. Finally, the effects of device structure on the sensitivities of perovskite thin-film microsensors are discussed. A new physical model is proposed for humidity-sensitive MIS capacitor with a metal-perovskite-SiO -Si structure. Based on this model, it is deduced that higher sensitivity of thinner film is due to higher porosity of the film. However, thinner film results in lower sensitivity to illumination due to poorer absorption, iii while the film thickness only has minor effects on the thermal sensitivity. The effects of SiO thickness are studied and experimental results demonstrate that an optimal value of 250 A gives rise to good multi-function sensitivities. The dependence of electrical properties of photoresistor on device dimension is investigated. Devices with smaller electrode spacings show reasonably linear I-V characteristics. Moreover, heat treatment in O for an optimal time can increase the photo sensitivity by suppressing dark current. In conclusion, SOI SRT sensors and perovskite-oxide thin-film microsensors are promising candidates for integrated sensor applications.

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1992 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sensors for In Situ and In Process Measurements in Microelectronics Manufacturing written by and published by . This book was released on 1995 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: This final report summarizes the progress we have made in developing ultrasonic sensors for in-situ monitoring of IC manufacturing processes. The work was done in collaboration with SRC funding. We report a temperature measurement technique based on the temperature dependence of acoustic wave velocity in silicon wafers. The zeroth order antisymmetric Lamb wave is excited in the wafer using the quartz pins which support the wafer during processing. Extensional waves are generated in the quartz pin by a PZT-5H transducer and the acoustic energy is coupled to the Lamb wave at the contact between the sharpened end of the pin and the wafer surface. The detection is done by a similarly modified quartz pin or pins. By measuring the time of flight of the Lamb wave in the wafer between the two pins, we have monitored the wafer temperature in-situ in the 20 - 1000 deg C range with + or - 1 accuracy. Theoretical models considering wave propagation and thin film effects on the technique are developed for direct comparison with experimental results. With 8 spring loaded pins placed on a circular array around the wafer, 28 different measurements are made giving information about different regions. Using tomographic reconstruction techniques, spatial temperature distribution with 2 cm pixel size is then calculated. Excellent agreement is observed between the readings of thermocouples attached to the wafer, and calculated values for ultrasonic tomography. A method for temperature tomography with a smaller number of sensors is also proposed based on theoretical calculations. jg p.1.

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1044 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Expanding the Vision of Sensor Materials written by Committee on New Sensor Technologies: Materials and Applications and published by National Academies Press. This book was released on 1995-07-06 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in materials science and engineering have paved the way for the development of new and more capable sensors. Drawing upon case studies from manufacturing and structural monitoring and involving chemical and long wave-length infrared sensors, this book suggests an approach that frames the relevant technical issues in such a way as to expedite the consideration of new and novel sensor materials. It enables a multidisciplinary approach for identifying opportunities and making realistic assessments of technical risk and could be used to guide relevant research and development in sensor technologies.

Download or read book Fabrication Characterization and Application of Metal Embedded Thin Film Sensors for Hostile Manufacturing Environments written by Xudong Cheng and published by . This book was released on 2008 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fabrication Characterization and Application of PZT silane Nano composite Thin film Sensors and Actuators written by Weiwei Xu and published by . This book was released on 2019 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: Structural health monitoring (SHM) plays a very important role in improving structural safety, preventing catastrophic failures and lowering maintenance costs. Current sensing methods have some limitations, such as being bulky, heavy, or brittle, making them unsuitable for SHM of composite structures. In response to the need for a flexible, printable sensor with low curing temperature, a nano-composite thin-film with additive manufacturing capability that consists of numerous lead-zirconate-titanate (PZT) nanoparticles embedded in a silane matrix is proposed and studied in this dissertation. This dissertation includes fabrication, characterization, and applications of proposed thin-films with rigid or flexible substrates and parallel-plate or interdigitated electrodes as piezoelectric actuators and sensors. Fabrication includes the following steps: First, PZT nanoparticles with size distribution ranging from 300 to 800 nanometers, are fabricated via hydrothermal synthesis.The PZT nanoparticles are then suspended in a silane-based fluid to form a PZT ink that can be printed, sprayed, or drop-cast onto a substrate. The deposited PZT ink is subsequently cured at low temperature (e.g., 120 7́ŒC) to form the PZT-silane thin- film sensor. A similar ink and thin-film sensor using crushed bulk PZT is also fabricated for comparison. The aerosol-jet printed results for both inks are provided and compared. Characterizing the material properties of the PZT-silane thin films includes two parts: dielectric and piezoelectric characterization. The dielectric constant and loss are measured through an impedance analyzer. Piezoelectric properties are estimated by applying a calibrated force directly onto the film while an accurate, double-end charge amplifier isolates and records the tiny induced charge from background electrical noise. A finite element model is created to simulate the experimental setup in order to estimate the piezoelectric coefficient d33 from the measurements. A PZT-silane nano-composite thin film with parallel-plate electrodes, drop-cast near the fixed edge of a thin flexible cantilever beam made of kapton, has been successfully demonstrated as an actuator. Velocity measurements at the free end are found to be in synchronization with actuation signals when driving the PZT-silane thin film actuator near natural frequencies of the beam. To demonstrate its validity as a vibration sensor, a PZT-silane thin film is attached to a square aluminum plate supported by four pillars. The frequency response of the charge measured from the PZT thin-film sensor is in close agreement with the vibration measurements from a laser Doppler vibrometer. PZT ink is drop-cast on a flexible substrate in two electrode formats for evaluation: parallel-plate and interdigitated electrodes (IDEs). The parallel-plate electrode format is difficult to implement, because silver electrodes cannot be properly printed onto the PZT film with high conductivity and dimension accuracy. In contrast, IDEs inkjet-printed onto a polyethylene terephthalate (PET) film demonstrate excellent resolution and conductivity. Sinusoidal voltage applied over the IDEs drives PZT thin-film with IDEs device into resonance serving as a resonator. PZT thin films with printed IDEs are demonstrated as vibration and strain sensors. Vibration tests are carried out on wing and beam structures with small angle oscillations. PZT thin-film with IDEs are attached on one side of these test structures and commercially acquired foil strain gauges on the other side for comparison and characterization. Strain and charge frequency domain measurements are recorded and amplitude peaks correlate to structural vibration frequencies. PZT-IDE sensor outputs at wing/beam oscillation frequency are found to increase with vibration amplitude and charge responses are approximately proportional to strain gauge outputs. This validates PZT-silane thin films with printed IDEs as strain sensors. The directional dependence of their sensing capability is demonstrated in theory, finite element analysis and experimentation. Two PZT-silane thin film devices with printed IDEs oriented 90 degrees apart show different sensitivities towards single-axis strain and experimentation proves PZT thin films with IDEs can distinguish strains in two dimensions.

Download or read book Thin film Thermo mechanical Sensors Embedded in Metallic Structures written by Anastasios Golnas and published by . This book was released on 1999 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: