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Strong pH-Dependent Near-Infrared Fluorescence in a Microbial Rhodopsin Reconstituted with a Red-Shifting Retinal Analogue
摘要： Near-infrared (NIR)-driven rhodopsins are of great interest in optogenetics and other optobiotechnological developments such as artificial photosynthesis and deep-tissue voltage imaging. Here we report the proton pump proteorhodopsin (PR) containing a NIR-active retinal analogue (PR:MMAR) exhibits intense NIR fluorescence at a quantum yield of 3.3%. This is 130 times higher than native PR (Lenz, M. O.; et al. Biophys J. 2006, 91, 255?262) and 3?8 times higher than the QuasAr and PROPS voltage sensors (Kralj, J.; et al. Science 2011, 333, 345?348; Hochbaum, D. R.; et al. Nat. Methods 2014, 11, 825?833). The NIR fluorescence strongly depends on the pH in the range of 6?8.5, suggesting potential application of MMAR-binding proteins as ultrasensitive NIR-driven pH and/or voltage sensors. Femtosecond transient absorption spectroscopy showed that upon near-IR excitation, PR:MMAR features an unusually long fluorescence lifetime of 310 ps and the absence of isomerized photoproducts, consistent with the high fluorescence quantum yield. Stimulated Raman analysis indicates that the NIR-absorbing species develops upon protonation of a conserved aspartate, which promotes charge delocalization and bond length leveling due to an additional methylamino group in MMAR, in essence providing a secondary protonated Schiff base. This results in much smaller bond length alteration along the conjugated backbone, thereby conferring significant single-bond character to the C13C14 bond and structural deformation of the chromophore, which interferes with photoinduced isomerization and extends the lifetime for fluorescence. Hence, our studies allow for a molecular understanding of the relation between absorption/emission wavelength, isomerization, and fluorescence in PR:MMAR. As acidification enhances the resonance state, this explains the strong pH dependence of the NIR emission.
关键词： stimulated Raman analysis,fluorescence,voltage sensor,rhodopsins,optogenetics,artificial photosynthesis,proteorhodopsin,femtosecond transient absorption spectroscopy,pH sensor,Near-infrared,voltage imaging
更新于2025-09-23 15:21:01
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Design and Implementation Low Cost of Photovoltaic Monitoring System Network Based on LoRaWAN
摘要： The photovoltaic systems sector is in full renovation continually demanding a new system that allows the user to monitor his project from long distance. One of the systems that is currently being implemented in photovoltaic farms is known as the Internet of Things. Through this system, it is intended that the user can know in the real time the status of his photovoltaic systems panels. This paper presents a new solution based on LoRaWAN technology that allows the user to have the necessary information to achieve high efficient of the photovoltaic systems panels. This system is to design and implement a new measuring circuit for measuring the output voltage and current of the PV panels from long distance by using LoRa Technology. To test the correct functioning of the device, two tests have been carried out. The first one corresponds to an essay in which the maximum distance at which a node can communicate with the gateway is measured. While the second test means measuring the voltage and current output of the photovoltaic panel of the full system. The main advantages of the final circuit can be used to monitor PV panels with low-cost, and to have high-efficiency performance from long distance.
关键词： photovoltaic system,IOT,LoRaWAN,LoRa,current sensor,smart monitoring,voltage sensor
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on Machine Learning, Big Data, Cloud and Parallel Computing (COMITCon) - Faridabad, India (2019.2.14-2019.2.16)] 2019 International Conference on Machine Learning, Big Data, Cloud and Parallel Computing (COMITCon) - IoT Enabled Real-Time Energy Monitoring for Photovoltaic Systems
摘要： The increasing demand for solar energy, high energy prices, and operational costs are all of which lead to several compelling reasons for the need for energy monitoring. In this paper, an Internet of Things based remote real-time energy monitoring system is developed to monitor the solar power generation. Various current and voltage sensors are integrated with a multipurpose microcontroller for aggregating the data. An IoT analytics platform is adapted to visualize the aggregated data and evaluate the energy generated for a given distributed generation system. This helps in continuous remote monitoring and results in improved efficiency of the power plants. The remote monitoring also helps in identifying various anomalies that may affect the operation of solar panels. The results depict the efficiency and error associated with the developed monitoring system, which proved to be better when compared with conventional energy monitoring systems.
关键词： Monitoring,Arduino Uno,PV Module,Current Sensor,Internet of Things (IoT),Voltage Sensor
更新于2025-09-16 10:30:52
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Output error of converse piezoelectric fiber voltage sensor caused by optical fiber factors
摘要： In fiber voltage sensor, imperfect fiber splicing angle and length difference between the sensing fiber and the compensating fiber usually influence the system output performance. This article established the mathematical model of the system output error using the Jones matrix and analyzed the relationship between the system output error and the above two error factors, respectively. The results show that the angle error of 90(cid:2) splice has a significant influence on the system output, and the tolerance of angle error varies with different test voltages. When the test voltage is higher than 6 kV, if the expected system error is less than 0.02%, the splicing angle error should be less than 0.15(cid:2). Additionally, the length difference also has a significant influence on the system output accuracy. The length difference between sensing fiber and compensating fiber should be less than 1 mm when the test voltage is 110 kV so that the system can meet the accuracy requirements of IEC 0.2s. This research provides a reference for the development of fiber voltage sensor based on the converse piezoelectric effect and also provides a basis for the design of intelligent power detection robot system.
关键词： Optical voltage sensor,mathematical modeling,converse piezoelectric effect,output error
更新于2025-09-12 10:27:22
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[IEEE 2018 International CET Conference on Control, Communication, and Computing (IC4) - Thiruvananthapuram (2018.7.5-2018.7.7)] 2018 International CET Conference on Control, Communication, and Computing (IC4) - Comparative Study of Adaptive Single Sensor Based MPPT for PV Applications with Conventional Algorithms
摘要： Photovoltaic (PV) Systems are becoming vital for the existence of mankind nowadays. From bulk power generation to space exploration applications, PV systems finds an important role. To extract power from PV device it has to be operated at its Maximum Power Point(MPP) for which different MPPT algorithms are used. On a relative study of these different MPPT algorithms it is found that most of them suffers from certain problems such as highly oscillatory response and slow tracking time. Most of these algorithms uses both current and voltage sensors, this adds to the issue of reliability of such MPPTs. Here in this study, a Single voltage sensor based Adaptive MPPT is using different MPPT compared with MATLAB/SIMULINK simulations.
关键词： MATLAB/Simulink,Adaptive Voltage Sensor based MPPT,Maximum Power Point Tracking (MPPT),Solar power,Single Ended Primary Inductance Converter (SEPIC)
更新于2025-09-04 15:30:14