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- 摘要
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- 实验方案
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A Multiport Converter Interfacing Solar Photovoltaic Modules and Energy Storage with DC Microgrid
摘要： A novel real-time optical fibre X-Ray dosimeter for monitoring the radiation pulses delivered from a clinical linear accelerator (Linac) is presented. The primary focus of the sensor is to measure low doses of ionising X-ray radiation in real time (limited to 0.1-ms gate time of the detector). The sensor tip material scintillates upon exposure to X-ray energy and the resultant low-level visible light signal is coupled to a polymethyl methacrylate plastic optical fibre, which is used to guide it towards a distal avalanche photodiode-based detector. The detector measures the low-level scintillating light from the sensor, thereby converting the ionizing radiation energy to a measurable signal with a time resolution of 0.1 ms. Results show that the scintillating optical fibre X-ray dosimeter is capable of capturing the individual X-Ray pulses delivered by the Linac during normal operation. Further examination of the results demonstrates that the sensor is capable of measuring dose rate and, hence, dose with a linearity (R2 = 0.9995 ? 0.9999) and in a highly repeatable manner for dose rates in the range 100 to 600 monitor units/min.
关键词： optical fibre sensors,X-ray dosimetry,Clinical external beam radiotherapy,fluorescent and luminescent sensors,real time radiation dose measurement
更新于2025-09-23 15:21:01
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Combined temperature and radiation effects on radiation sensitive single-mode optical fibers
摘要： A novel real-time optical fibre X-Ray dosimeter for monitoring the radiation pulses delivered from a clinical linear accelerator (Linac) is presented. The primary focus of the sensor is to measure low doses of ionising X-ray radiation in real time (limited to 0.1-ms gate time of the detector). The sensor tip material scintillates upon exposure to X-ray energy and the resultant low-level visible light signal is coupled to a polymethyl methacrylate plastic optical fibre, which is used to guide it towards a distal avalanche photodiode-based detector. The detector measures the low-level scintillating light from the sensor, thereby converting the ionizing radiation energy to a measurable signal with a time resolution of 0.1 ms. Results show that the scintillating optical fibre X-ray dosimeter is capable of capturing the individual X-Ray pulses delivered by the Linac during normal operation. Further examination of the results demonstrates that the sensor is capable of measuring dose rate and, hence, dose with a linearity (R2 = 0.9995 ? 0.9999) and in a highly repeatable manner for dose rates in the range 100 to 600 monitor units/min.
关键词： optical fibre sensors,X-ray dosimetry,Clinical external beam radiotherapy,fluorescent and luminescent sensors,real time radiation dose measurement
更新于2025-09-23 15:21:01
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[OSA Optical Fiber Sensors - Lausanne (2018..-..)] 26th International Conference on Optical Fiber Sensors - Thermal and Residual Strain Response of an FBG-Based Temperature Sensor Embedded in Carbon Fiber Reinforced Composites
摘要： A strain-free temperature sensor based on a fiber Bragg grating loosely embedded in carbon fiber reinforced polymers is investigated. The effects of different anti-stick materials for packaging on the temperature and residual-strain responses are evaluated.
关键词： Fiber optics sensors,Fiber Bragg gratings
更新于2025-09-23 15:21:01
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[IEEE 2019 28th Wireless and Optical Communications Conference (WOCC) - Beijing, China (2019.5.9-2019.5.10)] 2019 28th Wireless and Optical Communications Conference (WOCC) - Copyright Page
摘要： We experimentally demonstrate a surface-plasmon-resonance-based sensor capable of detecting polysaccharide molecules, such as Xanthan gum. Experimental results demonstrate that by attaching Concanavalin A to the gold nanothin-film chip of the sensor, a linear response of the change in reflected optical power to the dissolved Xanthan gum concentration is observed, demonstrating the ability of the developed sensor to detect Xanthan gum concentrations up to 0.22 g/L.
关键词： surface plasmon resonance,desalination,Biosensor,optical sensors,xanthan gum
更新于2025-09-23 15:21:01
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Optical oxygen sensing by MPA-capped CdTe quantum dots immobilized in mesoporous silica
摘要： A novel nanocomposite luminescent material was prepared by taking advantage of the versatile wet impregnation method for the dispersion of CdTe quantum dots (QDs) into mesoporous silica host matrix and thus providing great interaction between oxygen and QDs, with potential application in an optical oxygen sensor. The optical/spectroscopic properties of the QDs suspended in aqueous media and incorporated in mesoporous silica were evaluated as a function of aging time, temperature variation and oxygen concentration. Luminescence quenching studies were carried out for both QDs suspended in solution and loaded into the silica matrix, in the presence of varying O2 concentration. By Stern-Volmer plot analysis, obtained at different temperatures, it was possible to verify the existence of two types of emission quenching mechanisms for CdTe QDs. After aging for 120 days at room temperature, the QDs in colloidal suspension displayed a small red-shifted emission, which was interpreted as a decreased bandgap energy owing to the increase in the nanocrystal size. In contrast, the emission spectrum of CdTe QDs loaded into the mesoporous SiO2 matrix remained unchanged after aging for the same time at ambient temperature. The presented results will contribute to the discernment of oxygen quenching mechanisms and chemical stability of optical sensors based on CdTe QDs.
关键词： oxygen sensors,mesoporous silica,Quantum Dots,CdTe,wet impregnation,fluorescence quenching
更新于2025-09-23 15:21:01
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Optical sensors based on silver nanoparticles for determination of pharmaceuticals: An overview of advances in the last decade
摘要： This review focuses on optical nanosensors based on silver nanoparticles (Ag NPs) and demonstrates their applications in the determination of pharmaceutical compounds in the last decade. Such optical sensors have received high attention in the analytical field owing to their low cost and simplicity since they do not require any complex or expensive instrumentation. This article reviews Ag NP-based optical methods for the determination of pharmaceutical compounds from 2010 to 2020. The reported optical methods are classified into four types: spectrophotometry, spectrofluorimetry, scattering and chemiluminescence. Ag NPs play different roles in the different sensing platforms used by these methods, the details of which are carefully explained in this review. Moreover, the relevant analytical parameters of the developed methods are categorized by role and tabulated. It is hoped that this review will stimulate further research in this field with similar nanostructures.
关键词： Silver nanoparticles,Optical sensors,Pharmaceutical compounds
更新于2025-09-23 15:21:01
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - A side-polished macro bend fiber sensor for the efficient Detection of petrol adulteration
摘要： A side-polished macro bend fiber sensor is fabricated and demonstrated here. The working principle is based on the macro bending loss and evanescent field absorption. A sensitivity of 90nW/% and 45nW/% are obtained for low and high level of adulteration respectively.
关键词： Side-polished,Sensors,Plastic optical fibers (POFs),Petrol adulteration
更新于2025-09-23 15:21:01
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Development of a turn-on graphene quantum dot-based fluorescent probe for sensing of pyrene in water
摘要： Polycyclic aromatic hydrocarbons (PAHs) are potentially harmful pollutants that are emitted into the environment from a range of sources largely due to incomplete combustion. The potential toxicity and carcinogenic effects of these compounds warrants the development of rapid and cost-effective methods for their detection. This work reports on the synthesis and use of graphene quantum dots (GQDs) as rapid fluorescence sensors for detecting PAHs in water. The GQDs were prepared from two sources, i.e. graphene oxide (GO) and citric acid (CA) – denoted GO-GQDs and CA-GQDs, respectively. Structural and optical properties of the GQDs were studied using TEM, Raman, and fluorescence and UV-vis spectroscopy. The GQDs were then applied for detection of pyrene in environmental water samples based on a “turn-off-on” mechanism where ferric ions were used for turn-off and pyrene for turn-on of fluorescence emission. The fluorescence intensity of both GQDs was switched on linearly within the 2–10 × 10?6 mol L?1 range and the limits of detection were found to be 0.325 × 10?6 mol L?1 and 0.242 × 10?6 mol L?1 for GO-GQDs and CA-GQDs, respectively. Finally, the potential application of the sensor for environmental water samples was investigated using lake water and satisfactory recoveries (97–107%) were obtained. The promising results from this work demonstrate the feasibility of pursuing cheaper and greener environmental monitoring techniques.
关键词： Polycyclic aromatic hydrocarbons,Pyrene detection,Graphene quantum dots,Fluorescence sensors,Environmental water samples
更新于2025-09-23 15:21:01
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Wide band ridge gap waveguide (RGW) fan beam antenna with low side lobes based on parabolic reflector principle
摘要： Asthma is one of the most prevalent and costly chronic conditions in the United States, which cannot be cured. However, accurate and timely surveillance data could allow for timely and targeted interventions at the community or individual level. Current national asthma disease surveillance systems can have data availability lags of up to two weeks. Rapid progress has been made in gathering nontraditional, digital information to perform disease surveillance. We introduce a novel method of using multiple data sources for predicting the number of asthma-related emergency department (ED) visits in a specific area. Twitter data, Google search interests, and environmental sensor data were collected for this purpose. Our preliminary findings show that our model can predict the number of asthma ED visits based on near-real-time environmental and social media data with approximately 70% precision. The results can be helpful for public health surveillance, ED preparedness, and targeted patient interventions.
关键词： emergency department (ED) visits,Asthma,big data,environmental sensors,social media,predictive modeling
更新于2025-09-23 15:21:01
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[IEEE 2019 14th International Conference on Computer Engineering and Systems (ICCES) - Cairo, Egypt (2019.12.17-2019.12.17)] 2019 14th International Conference on Computer Engineering and Systems (ICCES) - Silicon photonic coupled-ring resonator in nested configuration comprising different length scales
摘要： Silicon photonics is continuing to develop for an increasing number of applications including data centers, miniaturized sensors and atomic clocks. The development involved the creation of the technology platform, design of innovative devices and developing models and methods for fabrication tolerance assessment. In our work, we suggest a novel structure for silicon photonic coupled-ring-resonator with an order of scale difference in the rings’ lengths and sensitivity analysis for this structure. The design consists of a long racetrack resonator of length 472.6 μm (sub-millimeter scale) nested by ring resonator of radius 25 μm. This radius was chosen to minimize bending losses. The coupling ratio of the directional couplers is designed to be 97/3. The suggested structure is fabricated by the IMEC fabrication facility which is using DUV lithography and silicon etching ePIXfab. The analysis shows that this structure can achieve higher finesse than the typical values of the conventional structure, even with reasonable fabrication tolerance. Experimentally a finesse of about 25 and a quality factor of about 17,000 is achieved. The proposed structure can improve the performance of optical sensing and filtering.
关键词： integrated sensors,silicon photonics,fabrication tolerance,finesse enhancement,nested filters,ring resonator
更新于2025-09-23 15:21:01