scholarly journals A Silicon Resonant Accelerometer Embedded in An Isolation Frame with Stress Relief Anchor

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 571 ◽  
Author(s):  
Jian Cui ◽  
Haibing Yang ◽  
Dong Li ◽  
Ziyang Song ◽  
Qiancheng Zhao
Keyword(s):  
Thermal Stress ◽  
Thermal Sensitivity ◽  
High Sensitivity ◽  
Measurement Range ◽  
Dominant Factor ◽  
Stress Effect ◽  
Temperature Drift ◽  
Significant Performance ◽  
The Stability ◽  
Resonant Accelerometer

Bias thermal sensitivity is a significant performance parameter of a silicon resonant accelerometer (SRA) and is normally used to evaluate the degree of engineering practicability. Theoretical analysis demonstrates that temperature-induced stress is the dominant factor that determines the bias temperature drift of the custom-designed SRA. To solve this issue, this paper presents an SRA embedded in an isolation frame with stress insensitive anchor that prevents the resonant beams suffering from the thermal stress along the sense axis and thus improving the bias stability. Moreover, a high sensitivity device is achieved by integrating the vibrating beams with the comb fingers without conventional additional mass design. The experimental results show that the nominal resonant frequency of the SRA is around 93 kHz with the sensitivity and nonlinearity of 223.7 Hz/g and 5.1‰. The thermal sensitivities of the two resonant beams are −27.6 ppm/°C and −28.8 ppm/°C, respectively, which can be considered as the results owing to temperature change of the Young’s modulus without the thermal stress effect. The bias thermal sensitivity and the stability (1σ) after compensation are tested to be approximately 0.7 mg/°C and 1 mg over the temperature range from −40 °C to 60 °C with ±80 g measurement range.

scholarly journals High Sensitivity Differential Giant Magnetoresistance (GMR) Based Sensor for Non-Contacting DC/AC Current Measurement

Sensors ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 323 ◽  
Author(s):  
Mușuroi ◽  
Oproiu ◽  
Volmer ◽  
Firastrau
Keyword(s):  
Measurement System ◽  
Giant Magnetoresistance ◽  
High Sensitivity ◽  
Measurement Range ◽  
Current Measurement ◽  
Local Fields ◽  
Temperature Drift ◽  
Wide Range ◽  
Extended Operation ◽  
High Flexibility

This paper presents the design and implementation of a high sensitivity giant magnetoresistance (GMR) based current sensor with a broad range of applications. The novelty of our approach consists in using a double differential measurement system, based on commercial GMR sensors, with an adjustable biasing system used to linearize the field response of the system. The work aims to act as a fully-operational proof of concept application, with an emphasis on the mode of operation and methods to improve the sensitivity and linearity of the measurement system. The implemented system has a broad current measurement range from as low as 75 mA in DC and 150 mA in AC up to 4 A by using a single setup. The sensor system is also very low power, consuming only 6.4 mW. Due to the way the sensors are polarized and positioned above the U-shaped conductive band through which the current to be measured is flowing, the differential setup offers a sensitivity of about between 0.0272 to 0.0307 V/A (signal from sensors with no amplifications), a high immunity to external magnetic fields, low hysteresis effects of 40 mA, and a temperature drift of the offset of about −2.59×10−4 A/°C. The system provides a high flexibility in designing applications where local fields with very low amplitudes must be detected. This setup can be redesigned for a wide range of applications, thus allowing further specific optimizations, which would provide an even greater accuracy and a significantly extended operation range.

scholarly journals Temperature-Insensitive Structure Design of Micromachined Resonant Accelerometers

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1544 ◽  
Author(s):  
Yonggang Yin ◽  
Zhengxiang Fang ◽  
Yunfeng Liu ◽  
Fengtian Han
Keyword(s):  
Thermal Stress ◽  
Temperature Sensitivity ◽  
Structure Design ◽  
Experimental Results ◽  
Stress Effect ◽  
Glass Technology ◽  
Temperature Drift ◽  
Die Attach ◽  
Bias Stability

Micromachined resonant accelerometers (MRAs), especially those devices fabricated by silicon on glass technology, suffer from temperature drift error caused by inherent thermal stress. This paper proposes two structure designs to attenuate the effect of thermal stress. The first MRA structure is realized by optimizing the locations of the bonding anchors and utilizing a special-shaped substrate to isolate the thermal stress generated during the die attach process. The second structure is designed using an isolation frame fixed by a single anchor to replace all dispersed anchors associated with the suspension beams and micro-levers. Simulated and experimental results show that both of the MRA structures can effectively reduce the thermal stress effect. The experimental results on one MRA prototype indicate that the differential temperature sensitivity reduces down to 1.9 μg/°C and its 15-day bias stability reaches 1.4 μg.

scholarly journals Development of TLC Chromatographic-Densitometric Procedure for Qualitative and Quantitative Analysis of Ceftobiprole

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 708
Author(s):  
Żaneta Binert-Kusztal ◽  
Małgorzata Starek ◽  
Joanna Żandarek ◽  
Monika Dąbrowska
Keyword(s):  
High Sensitivity ◽  
Biologically Active ◽  
Fifth Generation ◽  
Ich Guidelines ◽  
Relative Standard ◽  
Lipophilicity Parameter ◽  
Alkaline Environments ◽  
Acetic Acid Water ◽  
Cephalosporin Antibiotics ◽  
The Stability

Currently, there is still a need for broad-spectrum antibiotics. The new cephalosporin antibiotics include, among others, ceftobiprole, a fifth-generation gram-positive cephalosporin, active against Staphylococcus aureus methicillin agonist (MRSA). The main focus of the work was to optimize the conditions of ceftobiprole qualitative determination and to validate the developed procedure according to ICH guidelines. As a result of the optimization process, HPTLC Cellulose chromatographic plates as a stationary phase and a mixture consisting of ethanol:2-propanol: glacial acetic acid: water (4:4:1:3, v/v/v/v) as a mobile phase were chosen. The densitometric detection was carried out at maximum absorbance of ceftobiprole (λ = 232 nm). Next, the validation process of the developed procedure was carried out. The relative standard deviation (RSD) for precision was less than 1.65%, which proves the high compatibility of the results, as well as the LOD = 0.0257 µg/spot and LOQ = 0.0779 µg/spot values, which also confirm the high sensitivity of the procedure. The usefulness of the developed method for the stability studies of ceftobiprole was analyzed. Study was carried out under stress conditions, i.e., acid and alkaline environments, exposure to radiation imitating sunlight and high temperature (40–60 °C). It was found that cefotbiprole is unstable in an alkaline environment and during exposure to UV-VIS radiation. Moreover, the lipophilicity parameter, as a main physicochemical property of the biologically active compound, was determined using experimental and computational methods.

scholarly journals Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity

Sensors ◽  
2015 ◽  
Vol 15 (12) ◽  
pp. 30293-30310 ◽  
Author(s):  
Jing Zhang ◽  
Yan Su ◽  
Qin Shi ◽  
An-Ping Qiu
Keyword(s):  
High Sensitivity ◽  
Resonant Accelerometer

scholarly journals Nucleic-Acid-Binding Chromophores as Efficient Indicators of Aptamer-Target Interactions

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Kwabena Sarpong ◽  
Bhaskar Datta
Keyword(s):  
Nucleic Acid ◽  
High Sensitivity ◽  
Covalent Modification ◽  
Fluorescence Signal ◽  
Nucleic Acid Binding ◽  
Sensitivity And Selectivity ◽  
Target Molecules ◽  
Diagnostic Applications ◽  
The Stability ◽  
Simple Format

The binding affinity and specificity of nucleic acid aptamers have made them valuable candidates for use as sensors in diagnostic applications. In particular, chromophore-functionalized aptamers offer a relatively simple format for detection and quantification of target molecules. We describe the use of nucleic-acid-staining reagents as an effective tool for detecting and signaling aptamer-target interactions. Aptamers varying in size and structure and targeting a range of molecules have been used in conjunction with commercially available chromophores to indicate and quantify the presence of cognate targets with high sensitivity and selectivity. Our assay precludes the covalent modification of nucleic acids and relies on the differential fluorescence signal of chromophores when complexed with aptamers with or without their cognate target. We also evaluate factors that are critical for the stability of the complex between the aptamer and chromophore in presence or absence of target molecules. Our results indicate the possibility of controlling those factors to enhance the sensitivity of target detection by the aptamers used in such assays.

scholarly journals Non-invasive and high-throughput interrogation of exon-specific isoform expression

2021 ◽  
Author(s):  
Dong-Jiunn Jeffery Truong ◽  
Teeradon Phlairaharn ◽  
Bianca Eßwein ◽  
Christoph Gruber ◽  
Deniz Tümen ◽  
...  
Keyword(s):  
Stem Cells ◽  
High Throughput ◽  
High Throughput Screening ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Therapeutic Interventions ◽  
Dominant Factor ◽  
Reporter System ◽  
Isoform Expression ◽  
Induced Pluripotent

AbstractExpression of exon-specific isoforms from alternatively spliced mRNA is a fundamental mechanism that substantially expands the proteome of a cell. However, conventional methods to assess alternative splicing are either consumptive and work-intensive or do not quantify isoform expression longitudinally at the protein level. Here, we therefore developed an exon-specific isoform expression reporter system (EXSISERS), which non-invasively reports the translation of exon-containing isoforms of endogenous genes by scarlessly excising reporter proteins from the nascent polypeptide chain through highly efficient, intein-mediated protein splicing. We applied EXSISERS to quantify the inclusion of the disease-associated exon 10 in microtubule-associated protein tau (MAPT) in patient-derived induced pluripotent stem cells and screened Cas13-based RNA-targeting effectors for isoform specificity. We also coupled cell survival to the inclusion of exon 18b of FOXP1, which is involved in maintaining pluripotency of embryonic stem cells, and confirmed that MBNL1 is a dominant factor for exon 18b exclusion. EXSISERS enables non-disruptive and multimodal monitoring of exon-specific isoform expression with high sensitivity and cellular resolution, and empowers high-throughput screening of exon-specific therapeutic interventions.

Synthesis of ZrO2: Pr3+, Gd3+ nanocrystals for optical thermometry with thermal sensitivity above 2.32% K-1 over 270 K of sensing range

2021 ◽  
Author(s):  
Minghui Li ◽  
Jun Zhou ◽  
Ruoshan Lei ◽  
Huanping Wang ◽  
Feifei Huang ◽  
...  
Keyword(s):  
Thermal Sensitivity ◽  
High Sensitivity ◽  
Sensing Range ◽  
Optical Thermometry ◽  
Co Doped

Nowadays, there is an enthusiastic effort to develop the luminescent thermometers used for remote and high-sensitivity temperature readout over a wide sensing range. Herein, the Pr3+ and Gd3+ co-doped ZrO2...

Design of Photoionization Detector Based on the Miniature Gas Chromatography

2013 ◽  
Vol 823 ◽  
pp. 291-295 ◽  
Author(s):  
Shou Chen Chai ◽  
Peng Yang ◽  
Cheng Jia Yang ◽  
Chun Li Cai ◽  
Na Yu
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Ionization Chamber ◽  
High Sensitivity ◽  
Fast Response ◽  
Low Detection Limit ◽  
Photoionization Detector ◽  
Key Factor ◽  
The Stability ◽  
Sensitivity Detection

In the space restricted airtight environment that people lives in, detecting harmful gas by miniature gas chromatography is the practical requirement at present, however, PIDs performance is key factor that restrict the application of miniature gas chromatography, the redesign of the detectors gas route in this paper aiming at improve detectors stability observably, and schemed out miniature PID with high sensitivity, low detection limit and fast response. The result of the experiment shows that the detection limit is 0.04ppm, the sensitivity is 101mv/ppm,the stability is 0.04×10-6/24h,meeting the project requirement. Keywords: photoionization detector; ionization chamber; sensitivity; detection limit;

Discrete-Time H-Infinity Synthesis of Frequency-Shaped Sliding Mode Control for Suppression of Vibration With Multiple Peak Frequencies

2016 ◽  
Author(s):  
Minghui Zheng ◽  
Masayoshi Tomizuka
Keyword(s):  
High Frequency ◽  
Sliding Mode ◽  
Disk Drive ◽  
Sliding Surface ◽  
Surface Dynamics ◽  
H Infinity ◽  
High Frequencies ◽  
Multiple Peak ◽  
Significant Performance ◽  
The Stability

Vibration with multiple large peaks at high frequencies may cause significant performance degradation and have become a major concern in modern high precision control systems. To deal with such high-frequency peaks, it is proposed to design a frequency-shaped sliding mode controller based on H∞ synthesis. It obtains an ‘optimal’ filter to shape the sliding surface, and thus provides frequency-dependent control allocation. The proposed frequency-shaping method assures the stability in the presence of multiple-peak vibration sources, and minimizes the weighted H∞ norm of the sliding surface dynamics. The evaluation is performed on a simulated hard disk drive with actual vibration sources from experiments, and the effectiveness of large vibration peak suppression is demonstrated.

An improved car-following model considering the impact of safety messages

2018 ◽  
Vol 32 (32) ◽  
pp. 1850398 ◽  
Author(s):  
Tenglong Li ◽  
Fei Hui ◽  
Xiangmo Zhao
Keyword(s):  
Traffic Congestion ◽  
Dominant Factor ◽  
Velocity Difference ◽  
Car Following ◽  
Safety Message ◽  
Warning Messages ◽  
Gray Correlation ◽  
Car Following Model ◽  
The Stability ◽  
The Impact

The existing car-following models of connected vehicles commonly lack experimental data as evidence. In this paper, a Gray correlation analysis is conducted to explore the change in driving behavior with safety messages. The data mining analysis shows that the dominant factor of car-following behavior is headway with no safety message, whereas the velocity difference between the leading and following vehicle becomes the dominant factor when warning messages are received. According to this result, an extended car-following model considering the impact of safety messages (IOSM) is proposed based on the full velocity difference (FVD) model. The stability criterion of this new model is then obtained through a linear stability analysis. Finally, numerical simulations are performed to verify the theoretical analysis results. Both analytical and simulation results show that traffic congestion can be suppressed by safety messages. However, the IOSM model is slightly less stable than the FVD model if the average headway in traffic flow is approximately 14–20 m.

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