scholarly journals Calibration accuracy of laser calorimetry for common crystal geometries

2017 ◽  
Author(s):  
Istvan Balasa ◽  
Detlev Ristau ◽  
Yannick Willer ◽  
Hao Liu
Keyword(s):  
Calibration Accuracy ◽  
Laser Calorimetry

scholarly journals Aggregation affects optical properties and photothermal heating of gold nanospheres

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yiru Wang ◽  
Zhe Gao ◽  
Zonghu Han ◽  
Yilin Liu ◽  
Huan Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Cross Section ◽  
Laser Heating ◽  
Dipole Approximation ◽  
Gold Nanospheres ◽  
Extinction Cross Section ◽  
Heating Efficiency ◽  
Photothermal Heating ◽  
New Framework ◽  
Laser Calorimetry

AbstractLaser heating of gold nanospheres (GNS) is increasingly prevalent in biomedical applications due to tunable optical properties that determine heating efficiency. Although many geometric parameters (i.e. size, morphology) can affect optical properties of individual GNS and their heating, no specific studies of how GNS aggregation affects heating have been carried out. We posit here that aggregation, which can occur within some biological systems, will significantly impact the optical and therefore heating properties of GNS. To address this, we employed discrete dipole approximation (DDA) simulations, Ultraviolet–Visible spectroscopy (UV–Vis) and laser calorimetry on GNS primary particles with diameters (5, 16, 30 nm) and their aggregates that contain 2 to 30 GNS particles. DDA shows that aggregation can reduce the extinction cross-section on a per particle basis by 17–28%. Experimental measurement by UV–Vis and laser calorimetry on aggregates also show up to a 25% reduction in extinction coefficient and significantly lower heating (~ 10%) compared to dispersed GNS. In addition, comparison of select aggregates shows even larger extinction cross section drops in sparse vs. dense aggregates. This work shows that GNS aggregation can change optical properties and reduce heating and provides a new framework for exploring this effect during laser heating of nanomaterial solutions.

Low-power laser calorimetry with high resolution

1994 ◽  
Author(s):  
Hans W. Becker ◽  
Volker Scheuer ◽  
Theo T. Tschudi
Keyword(s):  
High Resolution ◽  
Low Power ◽  
Power Laser ◽  
Laser Calorimetry

A Self-Correcting and Self-Checking Gas Turbine Meter

1982 ◽  
Vol 104 (2) ◽  
pp. 143-149 ◽  
Author(s):  
W. F. Z. Lee ◽  
D. C. Blakeslee ◽  
R. V. White
Keyword(s):  
Gas Turbine ◽  
Operating Conditions ◽  
Exit Angle ◽  
Test Results ◽  
Main Rotor ◽  
Calibration Accuracy

A new metering concept of a self-correcting and self-checking turbine meter is described in which a sensor rotor downstream from the main rotor senses and responds to changes in the exit angle of the fluid leaving the main rotor. The output from the sensor rotor is then electronically combined with the output from the main rotor to produce an adjusted output which automatically and continuously corrects to original meter calibration accuracy. This takes place despite changes in retarding torques, bearing wear and/or upstream conditions occurring in field operations over those which were experienced during calibration. The ratio of the sensor rotor output to the main rotor output at operating conditions is also automatically and continuously compared with that at calibration conditions. This provides an indication of the amount of accuracy deviation from initial calibration that is being corrected by the sensor rotor. This concept is studied theoretically and experimentally. Both the theory and test results (laboratory and field) confirm the concept’s validity and practicability.

Automated SEM and EDS System to Monitor Instrument Health and Calibration Accuracy for Forensic Science

2012 ◽  
Vol 18 (S2) ◽  
pp. 28-29 ◽  
Author(s):  
R. Wuhrer ◽  
K. Mason
Keyword(s):  
Forensic Science ◽  
Calibration Accuracy

Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.

HIGH-PRECISION IN-FLIGHT CALIBRATION USING UNKNOWN LANDMARKS

2021 ◽  
Vol 4 ◽  
pp. 117-124
Author(s):  
Alexander Tkachenko ◽  
Keyword(s):  
Good Accuracy ◽  
Star Tracker ◽  
Coordinate Frame ◽  
Geometric Calibration ◽  
The Earth ◽  
Imaging Camera ◽  
Calibration Accuracy ◽  
Combined Algorithm ◽  
Fuzzy State ◽  
Fuzzy State Observer

An in-flight geometric calibration (further — calibration) is interpreted here as a procedure of making more preceise mutual attitude parameters of the onboard imaging camera and the star tracker. The problem of calibration is solved with using of observations of the landmarks from the orbit. In this work, the landmarks are considered as unknown in the sense that they may be identified on the several snapshots, they may be associated with synchronous data of the star tracker and GPS, but their location in the Earth coordinate frame is unknown. While unknown markers are used, it is more complicated to provide high accuracy of calibration than when geo-referenced markers are observed. In such a situation, improvement of the onboard devices and gauges and increasing of their accuracy strenghtens advisability of agreement of attainable accuracy of calculations while in-flight geometric calibration with accessible measurings accuracy. It concerns properly calibration so as geo-referencing of space snaps using results of calibration. In particular, it is important to consider how accuracy of calibration depends on the accuracy of specific measurings and initial data. Actuality of the considered problem is indisputable. Without its solution, attraction of high-accurate measurings is senseless. A main means of investigation is computer simulanion and analysis of its results. The combined algorithm is proposed for the processing of the calibration measuring equations. It consists of two independent parts. The first one belongs to author of this work and is based on photogrammetric condition of collinearity The second part belongs to D.V. Lebedev and is based on photogrammetric condition of coplanarity. The method of state estimation with high convergence characteristics — fuzzy state observer — is used for resolving of measuring equations. The results of above-mentioned calibration are fully fit for the geo-referencing of the unknown ground objects with acceptable accuracy. Computer simulation had demonsrated good accuracy of the proposed method of the in-flight geometric calibration using unknown landmarks in a combination with high-precise characteristics of used technical means. The simulation had shown the calibration accuracy on the level of 5 arc sec and accuracy of the geo-referencing on the level of 10–20 m. It is fully comparable with accuracy when geo-referenced markers are observated.

scholarly journals ISMAR: an airborne submillimetre radiometer

2017 ◽  
Vol 10 (2) ◽  
pp. 477-490 ◽  
Author(s):  
Stuart Fox ◽  
Clare Lee ◽  
Brian Moyna ◽  
Martin Philipp ◽  
Ian Rule ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
High Altitude ◽  
Next Generation ◽  
Ice Cloud ◽  
Calibration Accuracy ◽  
Cloud Ice

Abstract. The International Submillimetre Airborne Radiometer (ISMAR) has been developed as an airborne demonstrator for the Ice Cloud Imager (ICI) that will be launched on board the next generation of European polar-orbiting weather satellites in the 2020s. It currently has 15 channels at frequencies between 118 and 664 GHz which are sensitive to scattering by cloud ice, and additional channels at 874 GHz are being developed. This paper presents an overview of ISMAR and describes the algorithms used for calibration. The main sources of bias in the measurements are evaluated, as well as the radiometric sensitivity in different measurement scenarios. It is shown that for downward views from high altitude, representative of a satellite viewing geometry, the bias in most channels is less than ±1 K and the NEΔT is less than 2 K, with many channels having an NEΔT less than 1 K. In-flight calibration accuracy is also evaluated by comparison of high-altitude zenith views with radiative-transfer simulations.

scholarly journals High-Accuracy Calibration Based on Linearity Adjustment for Eddy Current Displacement Sensor

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2842 ◽  
Author(s):  
Wei Liu ◽  
Bing Liang ◽  
Zhenyuan Jia ◽  
Di Feng ◽  
Xintong Jiang ◽  
...  
Keyword(s):  
Eddy Current ◽  
Measurement Accuracy ◽  
Characteristic Curve ◽  
Calibration Method ◽  
High Accuracy ◽  
Output Characteristic ◽  
Displacement Sensor ◽  
Support Vector ◽  
Displacement Sensors ◽  
Calibration Accuracy

High precision position control is essential in the process of parts manufacturing and assembling, where eddy current displacement sensors (ECDSs) are widely used owing to the advantages of non-contact sensing, compact volume, and resistance to harsh conditions. To solve the nonlinear characteristics of the sensors, a high-accuracy calibration method based on linearity adjustment is proposed for ECDSs in this paper, which markedly improves the calibration accuracy and then the measurement accuracy. After matching the displacement value and the output voltage of the sensors, firstly, the sensitivity is adjusted according to the specified output range. Then, the weighted support vector adjustment models with the optimal weight of the zero-scale, mid-scale and full-scale are established respectively to cyclically adjust the linearity of the output characteristic curve. Finally, the final linearity adjustment model is obtained, and both the calibration accuracy and precision are verified by the established calibration system. Experimental results show that the linearity of the output characteristic curve of ECDS adjusted by the calibration method reaches over 99.9%, increasing by 1.9–5.0% more than the one of the original. In addition, the measurement accuracy improves from 11–25 μ m to 1–10 μ m in the range of 6mm, which provides a reliable guarantee for high accuracy displacement measurement.

scholarly journals An Analysis of the Optical System of a Length Measurement Comparator

Mechanika ◽  
2020 ◽  
Vol 26 (6) ◽  
pp. 518-525
Author(s):  
Rimantas LAZDINAS ◽  
Mindaugas JUREVICIUS ◽  
Vladas VEKTERIS ◽  
Vytautas TURLA ◽  
Eugenijus JURKONIS
Keyword(s):  
Optical System ◽  
Processing Speed ◽  
Length Measurement ◽  
Identification Algorithm ◽  
High Processing Speed ◽  
Image Blurring ◽  
Scale Calibration ◽  
Calibration Accuracy ◽  
The Impact ◽  
High Processing

In the paper, the optical system of a precise bar length measuring comparator is analysed. The requirements for such a system are determined and systematized. The impact of the resolution, signal discretization frequency, image blurring, bar edge measurement indeterminacy and camera noise on measuring the bar width and establishing the bar position is discussed upon. Various algorithms have been analysed and finally a bar edge identification algorithm oriented to the scale calibration accuracy and the high processing speed was proposed. In the end of the paper, conclusions are provided.

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