Self-calibrating System Research Articles

A dual emission ratiometric fluorescent probe constructed based on MOF-embedded dye for sequential detection of Al3+ and PPA

The ratiometric fluorescence probe has a self-calibration system that greatly reduces interference from the external environment, it has high sensitivity and accuracy in qualitative and quantitative experiments. In this work, a novel ratio fluorescence probe (RhB@1) was constructed by enclosing Rhodamine B (RhB) in the channel of [Cd2(H2L)2(1,4-bib)2]•DMA (H2L=2-hydroxyterephthalic acid, 1,4-bib=1, 4-bis (imidazol-1-ylmethyl) benzene). The probe can display dual emission characteristics under a single excitation. Al3+ ion was detected by RhB@1. The results showed that the fluorescence of 1 in RhB@1 was increased, the fluorescence of RhB is unchanged, and limit of detection (LOD) of Al3+ is as low as 20.9nM. Interestingly, when PPA (phenylpyruvic acid) is added to the mixture of RhB@1 and Al3+, PPA competes with RhB@1 for Al3+ result in achieving continuous ratio sensing of Al3+ and PPA, and LOD of PPA is 3.21nM. More importantly, the response of RhB@1 to Al3+ in tap water and PPA in artificial urine was quantitatively determined by label recovery method. The results showed that the recovery rate were 97.706%-99.060% (Al3+) and 94.732%-98.100% (PPA). In addition, we prepared a portable test paper modified with carboxymethyl cellulose. This test paper has obvious color change when detecting Al3+ under ultraviolet light, which is easy to detect Al3+ by naked eye.

Developing self-calibrating system for fiber Bragg grating based guided wave sensing under changing temperature conditions

Fiber Bragg grating (FBG) sensors have long been thought of as the ideal sensors for structural health monitoring (SHM) due to their small size, light weight, ability to be embedded and ability to be multiplexed. So, FBG sensors have been commonly used for strain based SHM. In recent times, a renewed interest is seen in the use of FBG sensors for guided wave (GW) measurements using the edge filtering approach which increases the sensitivity several folds. They offer several unique opportunities for GW based SHM such as allowing mode filtering, acoustic coupling, etc. Unfortunately, more wide spread research is limited by the steep learning curve. Also, the use of FBG in real applications is still in its infancy due to the need of calibration of the system when the ambient temperature conditions change. This paper precisely tries to address these two shortcomings. For overcoming the steep learning curve, a detailed discussion on the hardware for the FBG based GW sensing is provided. Following the discussion a step-by-step approach is outlined for incorporating the sensors. A detailed trouble-shooting guide is developed based on the immense experience of the authors in this field. This exercise will allow easier adoption of the technique and stimulate more research in the topic. The exercise also allows us to highlight the safeguards and the features that need to be included in the system which will be self-calibrating. Once the design parameters are established a self-calibrating autonomous FBG based sensing system is developed. The developed system is tested in ambient conditions over an extended period in the day capturing the ambient temperature changes. The system is also tested in a larger temperature range (25 ∘C–65 ∘C). The results indicate that indeed the self-calibrating system works effectively. Some sensitivity studies to determine the performance in terms of system reaction time have also been provided. Such a ‘smart’ autonomous system for GW sensing has not been presented to the best of the author’s knowledge and is the key novelty of the presented work. Furthermore, the detailed discussions and troubleshooting guide will help introduce more people to this field of study which will lead to more radical development of the field.

A tailor-made fluorescent ionic liquid integrating tetrapropylammonium hydroxide with 1-naphathoic acid to construct a dual-emitting fluoroprobe for sensing hydroquinone in environmental waters

Herein, a dual-emitting fluoroprobe was pioneered for the sensitive and selective detection of hydroquinone (HQ) in environmental waters, which was based on integration of a tailor-made fluorescent ionic liquid ([TBAOH][NA]) with Eu3+ (([TBAOH][NA]/Eu3+). HQ could substantially enhance the 365-nm fluorescence intensity (FI365) of [TBAOH][NA]/Eu3+, whereas no prominent variation ocurred in FI615. After HQ binding with [TBAOH][NA], the electronic structure of S1 was completely pi-pi*, and the orbital overlap of the latter was much higher, thereby promoting photon transitions. After some key factors were optimized using a central-composite-design (CCD) approach, this fluroprobe provided a linear response from 0.5 to 100 μM and detection limit of 0.15 μM for HQ assay, which was comparable to analytical performance by conventional HPLC-DAD analysis. Overall, the prominent advantages of as-developed fluoroprobe lie in two aspects: (1) Employing the ratio of two well-resolved emission and significantly differential responses to HQ greatly enhance sensitivity and accuracy through a self-calibration system; and (2) [TBAOH][NA] has not only the superiority of “green solvent” like conventional ionic liquids, but also possesses strong luminescence signal owing to introducing 1-naphathoic acid as an anion into tetrapropylammonium hydroxide. Consequently, this dual-emitting fluoroprobe is endowed with great potential in on-site and outdoor HQ monitoring.

A photoelectrochemical biosensor based on self-calibration platform of carbon-rich plasmonic probe with near-infrared driving signal amplification

Exploring the photochemical (PEC) method induced by low-energy light source makes great significance to achieve high stability and accurate analysis. A sensing platform driven by near-infrared (NIR) light was designed by making the biochemically encoded carbon rich plasmonic hybrid (CPH) probe, the peptide@C–Mo2C. The inherent plasmonic effect of C–Mo2C CPH can directly absorb NIR light, thus starting effective electronic-hole pairs separation. Moreover, the photothermal effect of C–Mo2C CPH also promoted the reaction yield of photothermal catalyst reaction on sensing interface to assist the PEC signal amplification. In the presence of target trypsin, it cleaves the peptides, resulting in the release of peptide@C–Mo2C probe from interface, which leads to a relative decrease in PEC signal. More importantly, a self-calibration system consisting of two independent PEC test channels attempted to eliminate the influence of background signal and baseline drift. The test channel was used to specify the recognition target, while the blank channel was used as a reference. Therefore, the signal difference between two channels was recorded, so as to obtain results with less error and higher stability. In this NIR driven PEC sensor, the carbon rich probe with direct and efficient NIR light conversion promoted the sensitivity and a self-calibration system guaranteed the stability which provided innovative thoughts for developing ingenious PEC sensor.

In-situ measurement and self-calibration system for high-power laser energy in ICF facilities

Precise real-time measurement of high-power laser energy is the foundation for ICF facilities to keep power and energy balance, which requires energy measurement equipment to maintain considerable linearity during a long operation period. The measurement accuracy, efficiency and calibration procedure stability were the key factors for ICF facilities' operation. This work proposed a new thermopile-type energy meter and calibration system to achieve high-precise in-situ measurement and calibrating of high-power laser energy. The study suggested that the thermal energy conversion, electric energy loading and metering, heat transfer, sensor temperature rise, sampling circuit and post-processing significantly affected the high-power laser energy measurement and calibration results. Besides, the whole numerical modeling process was established and verified by experiments on the energy transfer and physical quantity conversion process in energy measurement. The laser energy measurement and calibration system has self-calibration functions and stable operation through numerical simulation and optimization of the key factors. This study is of great significance for the high-power laser energy monitoring and output energy improvement of ICF facilities, broadening the method for the high-precision in-situ measurement system.

Wavelength calibration of a solar spectral irradiance radiometer and validation by correlation photon coincidence counting

Accurate wavelength calibration is the key to achieving accuracy observation of solar spectral irradiance. A wavelength calibration of solar spectral irradiance radiometer based on correlation photon radiation reference is proposed. The wavelengths of two channels of the solar spectral irradiance radiometer are calibrated by a Hg-Ar lamp and lasers. A collimating and focusing optics are designed to ensure that light can illuminate the slit vertically and without polarization. The optics can also keep the consistency of observing and self-calibration modes. The calibration equations of two channels are established. The wavelength deviations of two channels are −0.11 ∼ 0.07 nm and −0.085 ∼ 0.017 nm respectively. To validate the calibrated wavelength, channel 1 is selected as the inspection channel according to the spectral line number of the calibration lamp and the variation of the photon count rate. The motor position close to the calibration wavelength 763.511 nm is selected in channel 2, and the coincidence measurement is carried out to check the accuracy of wavelength calibration in channel 1. The deviation of wavelength around 408 nm is 1.139 nm. The experimental results show that the correlated photons self-calibration system can realize the calibration and validation of the system wavelength. The method can increase the number of calibration wavelengths and is suitable for both channels.

A Dual Self-Calibrating Framework for Noninvasive Fetal ECG R-Peak Detection

Fetal heart rate (fHR) is critical for assessing fetal health and diagnosing disorders such as fetal distress, congenital heart disease, and intrauterine growth retardation. With the rapid development of the Internet of Medical Things (IoT), fetal R-peak detection plays an important role in diagnosing heart defects during pregnancy. However, due to the nonlinear mixing of multiple sources in the non-invasive signals and the low signal-to-noise ratio (SNR), it is difficult to obtain accurate R-peak detection result. This article presents a dual Self-calibrating system based on a Spectral Attention Kernel Independent Component Analysis (SA-KICA) module and a Selfcalibrating fetal R-peak detection (SC-FRD) module. SA-KICA is an ICA-based calibration module constructed by SA mechanism, which was sought from Short-Time Fourier Transform (STFT) and was shipped back to original signal with convolution to achieve perfect maternal electrocardiogram (MECG) separation in high-dimensional linear separable space. Then a periodic and morphological based Channel Selector is designed to select the optimal MECG. After MECG removal, to further improve the performance of fetal R-peak detection, the SC-FRD module is introduced to utilize the interior peak information and selfcalibrating strategy, which includes variance-based fetal R-peak seed selection, time-varying coarse prediction and adaptive probability mask calibration. The proposed framework is a primary attempt to concurrently introduce the nonlinear feature, spectral information and self-calibrating strategy in the field of fetal ECG processing. The framework achieved excellent performance in fetal R-peak detection accuracy on a simulated dataset and two public datasets with varying divergence and richness of resources. The experimental results show that our framework is superior to existing methods and can be used as a potential fetal monitoring method in the application of Internet of Medical Things. The code is released in https://github.com/bfyjr/NI-FECG-Extraction.

Versatile Multi-LiDAR Accurate Self-Calibration System Based on Pose Graph Optimization

Versatile Multi-LiDAR Accurate Self-Calibration System Based on Pose Graph Optimization

A massively scalable Time-to-Digital Converter with a PLL-free calibration system in a commercial 130 nm process

A 33.6 ps LSB Time-to-Digital converter was designed in 130 nm BiCMOS technology. The core of the converter is a differential 9-stage ring oscillator, based on a multi-path architecture. A novel version of this design is proposed, along with an analytical model of linearity. The model allowed us to understand the source of the performance superiority (in terms of linearity) of our design and to predict further improvements. The oscillator is integrated in a event-by-event self-calibration system that allows avoiding any PLL-based synchronization. For this reason and for the compactness and simplicity of the architecture, the proposed TDC is suitable for applications in which a large number of converters and a massive parallelization are required such as High-Energy Physics and medical imaging detector systems. A test chip for the TDC has been fabricated and tested. The TDC shows a DNL≤1.3 LSB, an INL≤2 LSB and a single-shot precision of 19.5 ps (0.58 LSB). The chip dissipates a power of 5.4 mW overall.

Closed‐loop control for self‐calibration of accelerometer achieved through integrated sensor and actuator system

In-situ self-calibration can fundamentally solve the problem of long-term stability of the accelerometer. The implementation of external integrated micro structure to provide physical excitation has become an effective method to compensate for the long-term drift error of the accelerometer. A closed-loop self-calibration system for accelerometers by integrating sensors and actuators is presented. The piezoelectric MEMS microvibrator acts as an acceleration source, providing a standard acceleration for the accelerometer integrated on it. An optical displacement sensing system consisting of vertical cavity surface emitting laser (VCSEL) and photodiodes (PDs) detects the motion state of the microvibrator to achieve the accurate output by closed-loop control. The self-calibration process of the accelerometer is performed by establishing an error model of the accelerometer and a vibration model of the integrated micro-vibrator. The drift error of the accelerometer is compensated by obtaining the error coefficient and the compensation coefficient. It has been verified that the error of the self-calibrated accelerometer when performing 15 g acceleration output is less than 1.5%.

A self-calibration method for rotary tables’ five degrees-of-freedom error motions

The paper proposed a novel self-calibration method for five degrees-of-freedom error motions of rotary tables. Two encoders with multiple reading heads were installed on the spindle’s different positions to measure rotation angles. By analyzing indication differences between the reading heads, the two grid discs’ radial motions were obtained. After Fourier analysis, measurement errors caused by the installation errors of the grid discs were eliminated and two different positions’ error motions of the spindle were obtained. Therefore, the rotary table’s 5-DOF error motions, including angular positioning (ECC) error motions, radial (EXC, EYC) and tilt (EAC, EBC) error motions defined in ISO 230-7 and ANSI/AMSEB89.3.4, were self-calibrated. In order to verify the proposed self-calibration method, roundness errors of a cylinder were measured on a rotary table with a self-calibration system. During the measurement of the roundness errors, the error motions of the rotary table were measured simultaneously by the self-calibration system. After error compensations and eliminating influences of error motions of the rotary table, measurement data of the roundness errors were obtained. Compared with the calibration of three-point method for measuring roundness errors, the residual errors were less than ±0.5 μm. In order to verify dynamic measurement, external forces were loaded on the rotary table intentionally during the measurement process. The error motions of the rotary table changed with intermittent external forces, which were also detected accurately by the self-calibration system on line. After error compensations, the calibrations trend and magnitude with three-point method showed that error motions self-calibration of the rotary table are effectiveness and feasibility.

Coupler Integrated Microstrip Patch Linear Phased Array for Self-Calibration

In this letter, a coupler integrated microstrip patch linear phased array is proposed as a new self-calibration system. The proposed coupler placed along the edge of the microstrip patch antenna is weakly coupled to the antenna array. This allows self-calibration without affecting the radiation performance of the antenna array. A 1 × 4 coupler integrated patch linear phased array and a beamformer operating at 5.8 GHz were implemented to verify the new self-calibration system. The measurement result using the self-calibration is very close to the result with a vector network analyzer (VNA). The coupler integrated patch linear phased array proposed as a new self-calibration system has 0.22 dB root-mean-square error (RMSE) magnitude and 1.2° RMSE phase. The calibration method using a proposed antenna array is expected to on-site calibration.

Random phase-shifting digital holography based on a self-calibrated system.

Random phase-shifting digital holography based on a self-calibrated system is proposed. In the proposed method, the hologram and the calibration interference fringes can be recorded simultaneously in a single image based on the space-division-multiplexing technique. Three randomly phase-shifted holograms and corresponding interference fringes are recorded, and the phase-shifting amount between each two adjacent holograms is calculated by the sampling Moiré method from the calibration interference fringes. A reflective object is used to demonstrate the effectiveness of the proposed method in the numerical and experiment.

Near-Infrared Dual-Emission Ratiometric Fluorescence Imaging Nanoprobe for Real-Time Tracing the Generation of Endogenous Peroxynitrite in Single Living Cells and In Vivo.

Peroxynitrite (ONOO–) is a highly reactive nitrogen species with potent oxidant and nitrating properties. Its excessive generation can cause DNA and protein damage, thereby contributing to cell injury, and it is closely related to the development of many diseases. Thus, there is an urgent need for a reliable method to determine changes in the steady-state levels of ONOO– in vivo. Ratiometric imaging, due to its built-in self-calibration system, can reduce artifacts and enable reliable in vivo imaging. In this study, we designed and prepared near-infrared (NIR) biomass quantum dots (NI-BQDs) and covalently coupled them with the NIR dye Cyanine7 (Cy7) to construct an NIR dual-emission nanoprobe (NI-BQD-Cy7) for real-time tracing the generation of endogenous ONOO– in single living cells and in vivo by ratiometric fluorescence imaging. NI-BQD-Cy7 exhibited high detection sensitivity and selectivity for ONOO– in the mitochondria. Additionally, it can produce dual NIR fluorescence emission, thus allowing in situ ratiometric fluorescence imaging to real-time trace the generation and concentration changes of ONOO– in vivo. The application of the proposed NIR dual-emission nanoprobe can provide accurate information for the study of the biological function of ONOO– in single living cells and in vivo, and it is very useful to explain the mechanism of cell damage caused by ONOO–.

A local observability analysis method for a time-varying nonlinear system and its application in the continuous self-calibration system

A local observability analysis method for a time-varying nonlinear system and its application in the continuous self-calibration system

Self-calibration system for pragmatic failure in English-Chinese translation based on big data

Aiming at the problems of long time, high energy consumption and low accuracy of the current English-Chinese translation pragmatic self-calibration system, a design method of English-Chinese translation pragmatic self-calibration system based on big data is proposed. In the hardware part of the system, the framework of the pragmatic error self-calibration system is designed. The speech is converted into digital signals by the speech recognition module, and the recognised digital signals are translated into Chinese by the functions in the translation module. In the software part of the system, the sample risk minimisation algorithm is adopted to keep the loss function in the sample minimum, and the calibration model is built according to the linear search and feature selection results. The experimental results show that the energy consumption coefficient of the designed system varies from 0 to 1.5. The average calibration accuracy is 95% and the calibration accuracy is high.

Self-calibration system for pragmatic failure in English-Chinese translation based on big data

Aiming at the problems of long time, high energy consumption and low accuracy of the current English-Chinese translation pragmatic self-calibration system, a design method of English-Chinese translation pragmatic self-calibration system based on big data is proposed. In the hardware part of the system, the framework of the pragmatic error self-calibration system is designed. The speech is converted into digital signals by the speech recognition module, and the recognised digital signals are translated into Chinese by the functions in the translation module. In the software part of the system, the sample risk minimisation algorithm is adopted to keep the loss function in the sample minimum, and the calibration model is built according to the linear search and feature selection results. The experimental results show that the energy consumption coefficient of the designed system varies from 0 to 1.5. The average calibration accuracy is 95% and the calibration accuracy is high.

Development and Evaluation of a Calibrating System for the Application Rate Control of a Seed-Fertilizer Drill Machine with Fluted Rollers

Seed-fertilizer drill machines with fluted rollers generally utilize a calibrated relationship between the fluted-roller rotation speed and mass flow rate to control the application rate. However, this relationship model gradually deteriorates with operating time and is easily affected by working conditions. To maintain the initial operating accuracy, a self-calibrating system for adjusting the control model parameters was designed. It utilizes the application-rate information and fluted-rollers rotation speed data during the operation process to dynamically establish the calibrated relationship. During the field tests performed 18 times, the self-calibrating system could dynamically re-calibrate the relationship model. After the model parameters were updated, the application rate control system maintained a high accuracy level, though the relative deviation of control parameters was relatively higher. The average relative deviations between actual and theoretical cumulative application rates were 0.97% and 1.22% for seeding and fertilizing, respectively, and the standard deviations were 0.69% and 0.62%. Correspondingly, the average relative deviations of control parameters were 7.29% and 7.86%, and the standard deviations were 1.16% and 3.06%. These results indicate that the proposed method with closed-looped control can maintain high-quality control performance and improve the productivity of the drill machine, which will benefit the agricultural production.

Efficient Built-In Test and Calibration of High Speed Serial I/O Systems Using Monobit Signal Acquisition

This paper proposes a new high-speed self-calibrating digital transmitter with the ability to deliver high quality signals at low hardware cost. The proposed self-calibrating system performs on-line monitoring of the channel by performing measurements on the time-domain reflected (TDR) waveform. Unlike complex TDR instrumentation, the proposed system has the capability to reconstruct the reflected waveform using a single bit (monobit) sampler. Using very little hardware, a specific feature of the reflected waveform (area over time or integral) is extracted and used to drive a signal pre-emphasis scheme that maximizes the opening of the signal eye diagram without any communication with the receiver. The absence of such physical loopback significantly reduces the time and complexity of feedback based transmitter calibration techniques, especially where multiple transmission channels are concerned. Further, the proposed scheme is useful in the presence of single or multiple transmission line imperfections or defects. The proposed technique is implemented via a printed circuit board (PCB) prototype and measurement results demonstrate that it is capable of detecting defects in the digital I/O channel and adapting the channel to improve the received signal eye-diagram without direct feedback from the receiver.

Research on Self Calibration Technology for Precision Workpiece Measurement Based on Laser Doppler Vibrometer

This article introduces the present development status at home and abroad of laser Doppler vibrometer, and analyses the basic principle of self-calibration technique. The one-dimensional self-calibration measurement scheme is designed by laser Doppler vibrometer. Taking gear vibration measurement as an example, four laser Doppler vibrometer are used to construct the self-calibration measurement system. Based on the principle of self-calibration, the system of paraboloid measurement and modification of large satellite antenna and its measurement and modification process are designed.