NEW PIEZOELECTRIC SUBSTRATES FOR SAW DEVICES

2000 ◽  
Vol 10 (04) ◽  
pp. 1017-1068 ◽  
Author(s):  
JOHN A. KOSINSKI
Keyword(s):  
Power Flow ◽  
Piezoelectric Materials ◽  
Low Cost ◽  
Temperature Phase ◽  
Flow Angle ◽  
Recent Developments ◽  
Temperature Coefficient Of Frequency ◽  
Piezoelectric Coupling ◽  
Strong Candidate ◽  
Diffraction Effects

Recent developments in single crystal piezoelectric materials have focused on the search for "ideal" materials with zero temperature coefficient of frequency orientations featuring jointly high piezoelectric coupling, high intrinsic Q, zero power flow angle, and minimized diffraction effects. In addition, the desired materials should have no low temperature phase transitions, and a physical chemistry conducive to repeatable, low cost growth and wafer scale device production. As difficult as it might seem to find such "ideal" materials, three completely different but strong candidate materials have emerged recently: the quartz homeotype gallium orthophosphate, the quartz isotype calcium gallo-germanates (langasite, langanite, langatate, etc.), and diomignite (lithium tetraborate). The current state-of-the-art and prospects for future development of these materials are considered.

Calculated Optimal Cuts for SAW Applications of LGS Crystal

2012 ◽  
Vol 538-541 ◽  
pp. 2211-2214
Author(s):  
Hong Yang ◽  
Wen Qi Huang
Keyword(s):  
Power Flow ◽  
Electromechanical Coupling ◽  
Euler Angle ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Flow Angle ◽  
Anisotropic Factor ◽  
Optimal Region ◽  
Temperature Coefficient Of Frequency ◽  
Propagation Properties

Surface acoustic wave(SAW) propagation properties including propagation phase velocity, power flow angle(PFA), anisotropic factor, electromechanical coupling factor(k2) and temperature coefficient of frequency(TCF) are calculated in an optimal region defined by Euler angle (90o,0o~20o,0o~180o) for LGS crystal. It is concluded that the Euler angle (90o, 20o, 122.23o) and (90o, 17.5o, 121.9o) possess superior SAW performance, which have zero PFA, low TCF and moderate k2 simultaneously. We can give priority to these cut-types in the SAW applications at high temperature.

scholarly journals Magnetic iron oxide/clay nanocomposites for adsorption and catalytic oxidation in water treatment applications

2020 ◽  
Vol 18 (1) ◽  
pp. 1148-1166
Author(s):  
Ganjar Fadillah ◽  
Septian Perwira Yudha ◽  
Suresh Sagadevan ◽  
Is Fatimah ◽  
Oki Muraza
Keyword(s):  
Iron Oxide ◽  
Water Treatment ◽  
Photocatalytic Oxidation ◽  
Low Cost ◽  
Synthesis Method ◽  
Chemical Oxidation ◽  
Magnetic Iron Oxide ◽  
Oxidation Processes ◽  
Recent Developments ◽  
Physical And Chemical

AbstractPhysical and chemical methods have been developed for water and wastewater treatments. Adsorption is an attractive method due to its simplicity and low cost, and it has been widely employed in industrial treatment. In advanced schemes, chemical oxidation and photocatalytic oxidation have been recognized as effective methods for wastewater-containing organic compounds. The use of magnetic iron oxide in these methods has received much attention. Magnetic iron oxide nanocomposite adsorbents have been recognized as favorable materials due to their stability, high adsorption capacities, and recoverability, compared to conventional sorbents. Magnetic iron oxide nanocomposites have also been reported to be effective in photocatalytic and chemical oxidation processes. The current review has presented recent developments in techniques using magnetic iron oxide nanocomposites for water treatment applications. The review highlights the synthesis method and compares modifications for adsorbent, photocatalytic oxidation, and chemical oxidation processes. Future prospects for the use of nanocomposites have been presented.

scholarly journals Revisiting Electrochemical Biosensing in the 21st Century Society for Inflammatory Cytokines Involved in Autoimmune, Neurodegenerative, Cardiac, Viral and Cancer Diseases

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 189
Author(s):  
Susana Campuzano ◽  
Paloma Yáñez-Sedeño ◽  
José Manuel Pingarrón
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
Accurate Determination ◽  
Test Time ◽  
Electrochemical Biosensing ◽  
Recent Developments ◽  
Inflammatory Processes ◽  
Human Skills ◽  
Cancer Diseases

The multifaceted key roles of cytokines in immunity and inflammatory processes have led to a high clinical interest for the determination of these biomolecules to be used as a tool in the diagnosis, prognosis, monitoring and treatment of several diseases of great current relevance (autoimmune, neurodegenerative, cardiac, viral and cancer diseases, hypercholesterolemia and diabetes). Therefore, the rapid and accurate determination of cytokine biomarkers in body fluids, cells and tissues has attracted considerable attention. However, many currently available techniques used for this purpose, although sensitive and selective, require expensive equipment and advanced human skills and do not meet the demands of today’s clinic in terms of test time, simplicity and point-of-care applicability. In the course of ongoing pursuit of new analytical methodologies, electrochemical biosensing is steadily gaining ground as a strategy suitable to develop simple, low-cost methods, with the ability for multiplexed and multiomics determinations in a short time and requiring a small amount of sample. This review article puts forward electrochemical biosensing methods reported in the last five years for the determination of cytokines, summarizes recent developments and trends through a comprehensive discussion of selected strategies, and highlights the challenges to solve in this field. Considering the key role demonstrated in the last years by different materials (with nano or micrometric size and with or without magnetic properties), in the design of analytical performance-enhanced electrochemical biosensing strategies, special attention is paid to the methods exploiting these approaches.

scholarly journals Recent Developments of Antimony-Based Anodes for Sodium- and Potassium-Ion Batteries

2021 ◽  
Author(s):  
Bochao Chen ◽  
Ming Liang ◽  
Qingzhao Wu ◽  
Shan Zhu ◽  
Naiqin Zhao ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Low Cost ◽  
Potassium Ion ◽  
Research Progress ◽  
Research Directions ◽  
Weak Charge ◽  
Recent Developments ◽  
High Theoretical Capacity ◽  
Further Development ◽  
Sodium And Potassium

AbstractThe development of sodium-ion (SIBs) and potassium-ion batteries (PIBs) has increased rapidly because of the abundant resources and cost-effectiveness of Na and K. Antimony (Sb) plays an important role in SIBs and PIBs because of its high theoretical capacity, proper working voltage, and low cost. However, Sb-based anodes have the drawbacks of large volume changes and weak charge transfer during the charge and discharge processes, thus leading to poor cycling and rapid capacity decay. To address such drawbacks, many strategies and a variety of Sb-based materials have been developed in recent years. This review systematically introduces the recent research progress of a variety of Sb-based anodes for SIBs and PIBs from the perspective of composition selection, preparation technologies, structural characteristics, and energy storage behaviors. Moreover, corresponding examples are presented to illustrate the advantages or disadvantages of these anodes. Finally, we summarize the challenges of the development of Sb-based materials for Na/K-ion batteries and propose potential research directions for their further development.

The Single-Rotor Helicopter with Rigidly-Mounted Blades

1963 ◽  
Vol 67 (634) ◽  
pp. 651-663 ◽  
Author(s):  
R. R. Heppe
Keyword(s):  
General Public ◽  
Research Team ◽  
Low Cost ◽  
Second World War ◽  
Public Acceptance ◽  
World War ◽  
Mass Market ◽  
Recent Developments ◽  
Second World

For many years, studies of various light aircraft designs have been carried on by the Lockheed-California Company in search of a vehicle that had the potential of truly generating the “air age”—a vehicle which would perform a useful service to many people, in many jobs. Shortly after the Second World War, these studies were directed along the lines of present-day light aeroplanes, but were eventually discarded upon recognition of the limited utility of these vehicles when related to general public acceptance. However, in 1959, spurred by recent developments in VTOL craft, the Lockheed research team again raised the question, “Is it possible today to develop a vehicle of low cost and with sufficient utility to reach the mass market?”

scholarly journals Recent Developments of Reflectarray Antennas for Reconfigurable Beams Using Surface-Mounted RF-MEMS

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Eduardo Carrasco ◽  
Mariano Barba ◽  
Manuel Arrebola ◽  
Jose A. Encinar
Keyword(s):  
Phase Shifter ◽  
Rf Mems ◽  
Low Cost ◽  
Phase Control ◽  
Electronic Control ◽  
Delay Lines ◽  
Mems Switches ◽  
Manufacturing Complexity ◽  
Recent Developments ◽  
Control Devices

Some of the most recent developments in reconfigurable reflectarrays using surface-mounted RF-MEMS, which have been developed at the Universidad Politécnica de Madrid, are summarized in this paper. The results include reconfigurable elements based on patches aperture-coupled to delay lines in two configurations: single elements and gathered elements which form subarrays with common phase control. The former include traditional aperture-coupled elements and a novel wideband reflectarray element which has been designed using two stacked patches. The latter are proposed as a low cost solution for reducing the number of electronic control devices as well as the manufacturing complexity of large reflectarrays. The main advantages and drawbacks of the grouping are evaluated in both pencil and shaped-beam antennas. In all the cases, the effects of the MEMS switches and their assembly circuitry are evaluated when they are used in a 2-bit phase shifter which can be extended to more bits, demonstrating that the proposed elements can be used efficiently in reconfigurable-beam reflectarrays.

scholarly journals The power flow angle of acoustic waves in thin piezoelectric plates

2008 ◽  
Vol 55 (9) ◽  
pp. 1984-1991 ◽  
Author(s):  
I.E. Kuznetsova ◽  
B.D. Zaitsev ◽  
A.A. Teplykh ◽  
S.G. Joshi ◽  
A.S. Kuznetsova
Keyword(s):  
Acoustic Waves ◽  
Power Flow ◽  
Flow Angle ◽  
Piezoelectric Plates

scholarly journals Advances in the Structural Health Monitoring of Bridges Using Piezoelectric Transducers

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4312 ◽  
Author(s):  
Yunzhu Chen ◽  
Xingwei Xue
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Piezoelectric Materials ◽  
Low Cost ◽  
Rapid Development ◽  
Concrete Strength ◽  
Steel Corrosion ◽  
Fast Response ◽  
Future Application ◽  
Structural Health

With the rapid development of the world’s transportation infrastructure, many long-span bridges were constructed in recent years, especially in China. However, these bridges are easily subjected to various damages due to dynamic loads (such as wind-, earthquake-, and vehicle-induced vibration) or environmental factors (such as corrosion). Therefore, structural health monitoring (SHM) is vital to guarantee the safety of bridges in their service lives. With its wide frequency response range, fast response, simple preparation process, ease of processing, low cost, and other advantages, the piezoelectric transducer is commonly employed for the SHM of bridges. This paper summarizes the application of piezoelectric materials for the SHM of bridges, including the monitoring of the concrete strength, bolt looseness, steel corrosion, and grouting density. For each problem, the application of piezoelectric materials in different research methods is described. The related data processing methods for four types of bridge detection are briefly summarized, and the principles of each method in practical application are listed. Finally, issues to be studied when using piezoelectric materials for monitoring are discussed, and future application prospects and development directions are presented.

scholarly journals Shallow Water Bathymetry Inversion Using Hybrid Multi-band Composites Resulted from Integration of Drone-based RGB and Multispectral Imagery

2022 ◽  
Author(s):  
Evangelos Alevizos ◽  
Athanasios V Argyriou ◽  
Dimitris Oikonomou ◽  
Dimitrios D Alexakis
Keyword(s):  
Low Cost ◽  
Visible Spectrum ◽  
Small Scale ◽  
Multispectral Imagery ◽  
Depth Data ◽  
Recent Developments ◽  
Model Tuning ◽  
Inversion Techniques ◽  
Camera Sensors ◽  
Current Inversion

Shallow bathymetry inversion algorithms have long been applied in various types of remote sensing imagery with relative success. However, this approach requires that imagery with increased radiometric resolution in the visible spectrum is available. The recent developments in drones and camera sensors allow for testing current inversion techniques on new types of datasets. This study explores the bathymetric mapping capabilities of fused RGB and multispectral imagery, as an alternative to costly hyperspectral sensors. Combining drone-based RGB and multispectral imagery into a single cube dataset, provides the necessary radiometric detail for shallow bathymetry inversion applications. This technique is based on commercial and open-source software and does not require input of reference depth measurements in contrast to other approaches. The robustness of this method was tested on three different coastal sites with contrasting seafloor types. The use of suitable end-member spectra which are representative of the seafloor types of the study area and the sun zenith angle are important parameters in model tuning. The results of this study show good correlation (R2>0.7) and less than half a meter error when they are compared with sonar depth data. Consequently, integration of various drone-based imagery may be applied for producing centimetre resolution bathymetry maps at low cost for small-scale shallow areas.

scholarly journals Quantum Dot-sensitized Solar Cells: A Review

2018 ◽  
Vol 7 (1) ◽  
pp. 42-54 ◽  
Author(s):  
Pooja Bhambhani
Keyword(s):  
Solar Cell ◽  
Quantum Dot ◽  
Counter Electrode ◽  
Low Cost ◽  
Power Conversion ◽  
Counter Electrodes ◽  
Analogous Structure ◽  
Recent Developments ◽  
Working Principle ◽  
Sensitized Solar Cells

Quantum dot-sensitized solar cell (QDSSC) has an analogous structure and working principle to the dye sensitizer solar cell (DSSC). It has drawn great attention due to its unique features, like multiple exciton generation (MEG), simple fabrication and low cost. The power conversion efficiency (PCE) of QDSSC is lower than that of DSSC. To increase the PCE of QDSSC, it is required to develop new types of working electrodes, sensitizers, counter electrodes and electrolytes. This review highlights recent developments in QDSSCs and their key components, including the photoanode, sensitizer, electrolyte and counter electrode.

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