Design and performance of a large aperture, high-sensitivity, dynamic wavefront sensor

2004 ◽  
Author(s):  
Alan L. Wertheimer ◽  
David J. Fischer ◽  
Richard A. Hutchin
Keyword(s):  
High Sensitivity ◽  
Wavefront Sensor ◽  
Large Aperture ◽  
And Performance

scholarly journals Biological nanoscale fluorescent probes: From structure and performance to bioimaging

2020 ◽  
Vol 39 (1) ◽  
pp. 209-221
Author(s):  
Jiafeng Wan ◽  
Xiaoyuan Zhang ◽  
Kai Zhang ◽  
Zhiqiang Su
Keyword(s):  
Fluorescent Probes ◽  
Organic Dyes ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
High Sensitivity ◽  
Biological Imaging ◽  
Fluorescent Materials ◽  
And Performance

Abstract In recent years, nanomaterials have attracted lots of attention from researchers due to their unique properties. Nanometer fluorescent materials, such as organic dyes, semiconductor quantum dots (QDs), metal nano-clusters (MNCs), carbon dots (CDs), etc., are widely used in biological imaging due to their high sensitivity, short response time, and excellent accuracy. Nanometer fluorescent probes can not only perform in vitro imaging of organisms but also achieve in vivo imaging. This provides medical staff with great convenience in cancer treatment. Combined with contemporary medical methods, faster and more effective treatment of cancer is achievable. This article explains the response mechanism of three-nanometer fluorescent probes: the principle of induced electron transfer (PET), the principle of fluorescence resonance energy transfer (FRET), and the principle of intramolecular charge transfer (ICT), showing the semiconductor QDs, precious MNCs, and CDs. The excellent performance of the three kinds of nano fluorescent materials in biological imaging is highlighted, and the application of these three kinds of nano fluorescent probes in targeted biological imaging is also introduced. Nanometer fluorescent materials will show their significance in the field of biomedicine.

scholarly journals Simulation and performance analysis of Multiple PCS sensors system

2017 ◽  
Vol 20 (2) ◽  
pp. 85
Author(s):  
Pawan Whig ◽  
Syed Naseem Ahmad ◽  
Surinder Kumar
Keyword(s):  
Low Cost ◽  
Reference Electrode ◽  
Oxygen Demand ◽  
High Sensitivity ◽  
Readout Circuit ◽  
Active Components ◽  
Multiple Sensors ◽  
Quality Of Water ◽  
Voltage Signal ◽  
And Performance

In this paper, a novel circuit is presented which overcome a serious limitation found in case of multiple sensors system. In this novel system design only one reference electrode and few active components used that makes the implementation of a low-cost system for the supervision of water quality. Photo Catalytic Sensor (PCS) estimates the parameter BOD (Biological Oxygen Demand) which is generally used to estimate quality of water. The system proposed in this paper involves a balanced bridge approach using few electronic components that provides a correlation in the input-output signals of low-cost sensors. The main reason of employing a readout circuit to PCS circuitry, is the fact that the fluctuation of O2 influences the threshold voltage, which is internal parameter of the FET and can manifest itself as a voltage signal at output but as a function of the trans conductance gain. The trans-conductance is a passive parameter and in order to derive voltage or current signal from its fluctuations the sensor has to be attached to readout circuit. This circuit provides high sensitivity to the changes in percentage of O2 in the solution.

Image Encryption Algorithm Based on a Novel 4D Chaotic System

2021 ◽  
Vol 15 (4) ◽  
pp. 118-131
Author(s):  
Sadiq A. Mehdi
Keyword(s):  
Chaotic System ◽  
Initial Conditions ◽  
High Sensitivity ◽  
Encryption Algorithm ◽  
Pseudorandom Sequence ◽  
Key Space ◽  
Xor Operation ◽  
Change Intensity ◽  
And Performance ◽  
Image Cryptosystem

In this paper, a novel four-dimensional chaotic system has been created, which has characteristics such as high sensitivity to the initial conditions and parameters. It also has two a positive Lyapunov exponents. This means the system is hyper chaotic. In addition, a new algorithm was suggested based on which they constructed an image cryptosystem. In the permutation stage, the pixel positions are scrambled via a chaotic sequence sorting. In the substitution stage, pixel values are mixed with a pseudorandom sequence generated from the 4D chaotic system using XOR operation. A simulation has been conducted to evaluate the algorithm, using the standardized tests such as information entropy, histogram, number of pixel change rate, unified average change intensity, and key space. Experimental results and performance analyses demonstrate that the proposed encryption algorithm achieves high security and efficiency.

Easy-to-Fabricate K2Pd(SO3)2-Dyed Polyester Fabric with Highly Selective and Fast Response to Carbon Monoxide

2021 ◽  
Vol 21 (8) ◽  
pp. 4400-4405
Author(s):  
Junyeop Lee ◽  
Nam Gon Do ◽  
Dong Hyuk Jeong ◽  
Sae-Wan Kim ◽  
Maeum Han ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Color Change ◽  
High Sensitivity ◽  
Cost Effective ◽  
Fast Response ◽  
Polyester Fabric ◽  
High Porosity ◽  
Sensing Material ◽  
Sensitivity And Selectivity ◽  
And Performance

Carbon monoxide (CO) is an odorless, colorless, tasteless, extremely flammable, and highly toxic gas. It is produced when there is insufficient oxygen supply during the combustion of carbon to produce carbon dioxide (CO2). CO is produced from operating engines, stoves, or furnaces. CO poisoning occurs when CO accumulates in the bloodstream and can result in severe tissue damage or even death. Many types of CO sensors have been reported, including electrochemical, semiconductor metal-oxide, catalytic combustion, thermal conductivity, and infrared absorption-type for the detection of CO. However, despite their excellent selectivity and sensitivity, issues such as complexity, power consumption, and calibration limit their applications. In this study, a fabricbased colorimetric CO sensor is proposed to address these issues. Potassium disulfitopalladate (II) (K2Pd(SO3)2) is dyed on a polyester fabric as a sensing material for selective CO detection. The sensing characteristics and performance are investigated using optical instruments such as RGB sensor and spectrometer. The sensor shows immediate color change when exposed to CO at a concentration that is even lower than 20 ppm before 2 min. The fast response time of the sensor is attributed to its high porosity to react with CO. This easy-to-fabricate and cost-effective sensor can detect and prevent the leakage of CO simultaneously with high sensitivity and selectivity toward CO.

scholarly journals Fabrication and Characterization of Humidity Sensors Based on Graphene Oxide–PEDOT:PSS Composites on a Flexible Substrate

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 148 ◽  
Author(s):  
Francisco J. Romero ◽  
Almudena Rivadeneyra ◽  
Markus Becherer ◽  
Diego P. Morales ◽  
Noel Rodríguez
Keyword(s):  
Graphene Oxide ◽  
Large Scale ◽  
Flexible Substrate ◽  
High Sensitivity ◽  
Cost Effective ◽  
Humidity Sensors ◽  
Good Thermal Stability ◽  
Cost Effective Method ◽  
And Performance ◽  
Stability Time

In this paper, we present a simple, fast, and cost-effective method for the large-scale fabrication of high-sensitivity humidity sensors on flexible substrates. These sensors consist of a micro screen-printed capacitive structure upon which a sensitive layer is deposited. We studied two different structures and three different sensing materials by modifying the concentration of poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) in a graphene oxide (GO) solution. The results show that the aggregation of the PEDOT:PSS to the GO can modify its electrical properties, boosting the performance of the capacitive sensors in terms of both resistive losses and sensitivity to relative humidity (RH) changes. Thus, in an area less than 30 mm2, the GO/PEDOT:PSS-based sensors can achieve a sensitivity much higher (1.22 nF/%RH at 1 kHz) than other similar sensors presented in the literature which, together with their good thermal stability, time response, and performance over bending, demonstrates that the manufacturing approach described in this work paves the way for the mass production of flexible humidity sensors in an inexpensive way.

A review: metamaterial sensors for material characterization

Sensor Review ◽  
2019 ◽  
Vol 39 (3) ◽  
pp. 417-432 ◽  
Author(s):  
A. Vivek ◽  
K. Shambavi ◽  
Zachariah C. Alex
Keyword(s):  
Material Characterization ◽  
Research Work ◽  
Wave Interaction ◽  
High Sensitivity ◽  
Electromagnetic Spectrum ◽  
Label Free ◽  
Content Type ◽  
Work Related ◽  
Sensing Application ◽  
And Performance

Purpose This paper aims to focus on research work related to metamaterial-based sensors for material characterization that have been developed for past ten years. A decade of research on metamaterial for sensing application has led to the advancement of compact and improved sensors. Design/methodology/approach In this study, relevant research papers on metamaterial sensors for material characterization published in reputed journals during the period 2007-2018 were reviewed, particularly focusing on shape, size and nature of materials characterized. Each sensor with its design and performance parameters have been summarized and discussed here. Findings As metamaterial structures are excited by electromagnetic wave interaction, sensing application throughout electromagnetic spectrum is possible. Recent advancement in fabrication techniques and improvement in metamaterial structures have led to the development of compact, label free and reversible sensors with high sensitivity. Originality/value The paper provides useful information on the development of metamaterial sensors for material characterization.

HARTMANN-SHACK WAVEFRONT SENSOR IN THE EYE: ACCURACY AND PERFORMANCE LIMITS

1999 ◽  
Author(s):  
PABLO ARTAL ◽  
JUAN L. ARAGON ◽  
PEDRO M. PRIETO ◽  
FERNANDO VARGAS-MARTIN ◽  
ESTHER BERRIO
Keyword(s):  
Wavefront Sensor ◽  
Performance Limits ◽  
And Performance

WATT MATTERS MOST? DESIGN SPACE EXPLORATION OF HIGH-PERFORMANCE MICROPROCESSORS FOR POWER-PERFORMANCE EFFICIENCY

2007 ◽  
Vol 16 (03) ◽  
pp. 357-378
Author(s):  
PEDRO TRANCOSO
Keyword(s):  
High Performance ◽  
Design Space Exploration ◽  
High Sensitivity ◽  
Clock Frequency ◽  
Power Performance ◽  
Large Power ◽  
Multiple Parameters ◽  
And Performance ◽  
The One ◽  
Power Awareness

Computer systems have evolved significantly in the last years leading to high-performance systems. This, however, has come with a cost of large power dissipation. As such, power-awareness has become a major factor in processor design. Therefore, it is important to have a complete understanding of the power and performance behavior of all processor components. In order to achieve this, the current work presents a comprehensive analysis of power-performance efficiency for different high-end microarchitecture configurations using three different workloads: multimedia, scientific, and database. The objectives of this work are: (1) to analyze and compare the power-performance efficiency for different workloads; (2) to present a sensitivity analysis for the microarchitecture parameters in order to identify which ones are more sensitive to changes in terms of power-performance efficiency; and (3) to propose power-performance efficient configurations for each workload. The simulation results show that the multimedia workload is the one achieving the highest efficiency but the database workload is the most sensitive to parameter changes. In addition, the results also show that the parameter sensitivity depends significantly on the workload. While the issue width and clock frequency present very high sensitivity across all workloads (approximately 100%), for the database workload, the first-level instruction cache size shows an even higher sensitivity (149%). The correct configuration of these microarchitecture parameters is essential. A careless configuration of a single parameter from a baseline setup may result in a loss of the power-performance efficiency of up to 99%. Finally, carefully tuning multiple parameters simultaneously may result in gains up to 154% over the power-performance efficiency of the baseline configuration.

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