- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Simulation and experimental study of the angle-dependent sensitivity of the thick pinhole used for gamma imaging
摘要： The angle-dependent sensitivity of rotationally symmetric thick pinholes used for gamma imaging was investigated using a geometric algorithm and Monte Carlo numerical simulations for the thick pinholes with different structural parameters. The effect of the pinhole diameter, the thickness of the straight-hole portion, and the half conical angle were analyzed. The point source was demonstrated to be a feasible replacement for the homogeneous plane source through theoretical deduction, numerical calculations, and experimental measurements of the angle-dependent sensitivity. A small quasi-point source was established based on a 10K curie level 60Co gamma ray source in the experimental measurement of the angle-dependent sensitivity. The image position remained unchanged and image distortion was avoided by rotating the thick pinhole around the pinhole center. The experimental result was in good agreement with the theoretical calculation, indicating the potential of this measurement method.
关键词： angle-dependent sensitivity,Monte Carlo method,quasi-point source,geometrical numerical algorithm,thick pinhole imaging
更新于2025-09-23 15:21:01
-
Facile synthesis of fluorescent carbon quantum dots from Betel leafs (Piper betle) for Fe3+sensing
摘要： In this study green synthesis of Fluorescence Carbon quantum dots from betel leafs (piper betle) via hydrothermal method. The characterization of CQDs was carried out and their feasible development mechanism was also discussed. This carbon dots selectively detects Fe3+ in aqueous medium in the presence of other metal ions like (Ca2+, Cu2+, Mg2+, Ag+, Hg2+, Fe2+, Fe3+, Cd2+ and Pb2+) at same concentration and also very sensitivity it will detect 50–150 nM concentration with R2 = 0.9944 value.
关键词： Betel leafs,Sensitivity,Fluorescence,Fe3+ detection,Carbon quantum dots
更新于2025-09-23 15:21:01
-
An ultrasensitive luteolin sensor based on MOFs derived CuCo coated nitrogen-doped porous carbon polyhedron
摘要： Designing high-efficiency electrocatalysts for luteolin detection is essential and vital in biological and medical field. Herein, CuCo coated nitrogen-enriched porous carbon polyhedron (CuCo@NPCP) materials are fabricated as a highly sensitive electrochemical luteolin sensor by simple and mild approach. As characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption isotherms and electrochemical methods, CuCo@NPCP materials possess high specific surface area, 3D porous framework, amounts of available active sites, which all contribute to the adsorption and catalysis for luteolin. Meanwhile, vast mesoporous structure of CuCo@NPCP further affords more mass transport channels and enhances the mass transfer capacity. Thanks to above-mentioned characteristics, optimal Cu1Co3@NPCP presents superior analytical performance: a wide linear range from 0.2 nM to 2.5 μM, a ultrahigh sensitivity of 134.57 μA μM-1 surpassing to other reported catalysts previously, a low detection limit of 0.08 nM, as well as satisfactory selectivity, reproducibility, and long-term stability. This work offers an attractive catalyst derived from MOFs for constructing effective luteolin sensors.
关键词： Luteolin sensor,Metal-organic framework derivatives,Ultrahigh sensitivity,Trace detection
更新于2025-09-23 15:21:01
-
A new type of structure of optical fiber pressure sensor based on polarization modulation
摘要： In this study, a new type of structure of optical fiber pressure sensor (OFPS) based on polarization modulation is proposed, which selects a high-birefringence fiber (HBF) as the sensing unit to measure the pressure in the fluid medium. The PM-1550-01 fiber produced by NTK Photonics Inc. is evaluated as the sample in our subject. Firstly, the regularities of birefringence variation on the PM-1550-01 followed by the external pressure load and the ambient temperature are analyzed by the finite element method (FEM). The results show that the pressure sensitivity is 2.05 × 10 ? 6 RIU/MPa in the pressure range of 0–100 MPa, and the temperature sensitivity is 7.27 × 10 ? 10 RIU/°C in the temperature range of 0–100 °C. Thus, the pressure-temperature cross-sensitivity is only 0.355 kPa/°C in theory. Secondly, the expression of the output light intensity of the introduced OFPS is deduced based on the principles of polarization interference and phase modulation. Combined with simulation results, the measurement ranges of the sensor can be set and adjusted by the length of the sensing unit. Finally, the proposed OFPS is fabricated and external pressure tests within the range of 0–50 MPa are completed. The results show that the pressure sensitivity is approximately 0.145 dB/MPa in the pressure range of 0–44 MPa. There is a fine consistency between the experimental data and simulation results. In addition, the proposed OFPS has many other advantages, such as small size, simple fabrication process and large measurement range, which make it appropriate to be applied in high-pressure measurement in hostile conditions, e.g., downhole and ocean-bottom.
关键词： Low temperature cross-sensitivity,Polarization modulation,High-birefringence fiber,Optical fiber pressure sensor
更新于2025-09-23 15:21:01
-
High sensitivity surface plasmon resonance sensor based on D-shaped photonic crystal fiber with circular layout
摘要： A high sensitivity D-shaped photonic crystal fiber sensor based on surface plasmon resonance is proposed for refractive index sensing. By using finite element method, the sensing properties of the proposed sensor are investigated. The numerical results show a very high average sensitivity of 14600 nm/RIU with the high resolution of 6.80 × 10?6 RIU for refractive index (RI) of analytes ranging from 1.420 to 1.435. The layout of the air holes is designed to be circular and only two layers in this D-shaped photonic crystal fiber. The metallic gold is used as the surface plasmon resonance activity material, which is deposited on the polishing surface. The analyte is placed on the outer layer of the D-shaped photonic crystal fiber. This D-shaped photonic crystal fiber solves the difficulty of gold-plated film and fill analyte in the holes. The proposed PCF structure is a combination of circular layout and D-shaped, which also leads to the proposed sensor easy to fabricate and has considerable sensitivity.
关键词： Sensitivity,Photonic crystal fiber,Refractive index sensor,Surface plasmon resonance
更新于2025-09-23 15:21:01
-
Three-core photonic crystal fiber surface plasmon resonance sensor
摘要： A three-core photonic crystal fiber (PCF) surface plasmon resonance (SPR) biosensor with high performance is presented. The structure of the biosensor is easy to implement and has good repetition. The outer layer of the fiber structure is gold film. The analyte is placed on the surface of the gold film. The Full vector finite element method is used to numerical simulation and analysis the transmission mode and characteristics of the three-core PCF-SPR biosensor. The influence of sensor structure parameters on sensing performance is investigated. The structure parameters are optimized. The optimum structure parameters are given. The refractive index (RI) sensitivity of the sensor is discussed there. The results show that the average refractive index sensitivity of the sensor is 3435 nm/RIU in the sensing range of 1.33–1.40, and the resolution is 2.91 × 10?6 RIU. The sensor has the advantages of high sensitivity and high resolution. And it can be applied to real-time detection of the bio-molecules and small drug-molecules.
关键词： Photonic crystal fiber,Biosensor,Surface plasmon resonance,Refractive index sensitivity,Finite element method
更新于2025-09-23 15:21:01
-
A Phase Sensitivity-Enhanced Surface Plasmon Resonance Biosensor Based on ITO-Graphene Hybrid Structure
摘要： In this paper, a surface plasmon resonance (SPR) sensor based on the hybrid structure of silver (Ag)-indium tin oxide (ITO)-graphene is proposed and investigated. SPR biosensors are subdivided into three kinds of structures Ag, Ag-graphene, and Ag-ITO-graphene, when carried out using their respective optimized structure parameters. According to our analysis and comparison, the ITO-assisted SPR biosensor has an optimal reflectivity of 3.587 × 10?8 and a maximum phase sensitivity of 1.707 × 106°/RIU, which shows that ITO can be employed to further enhance the SPR sensing performance even with the existence of graphene.
关键词： Surface-plasmon-resonance,Hybrid structure,Phase sensitivity,Reflectivity
更新于2025-09-23 15:21:01
-
High-sensitivity strain sensor with an in-fiber air-bubble Fabry-Perot interferometer
摘要： We present a laser machining method for fabricating an all-fiber pillar-in-bubble Fabry-Perot interferometer (FPI), which is used for strain sensors with high sensitivity. The micro-structure of the air-bubble is fully controllable, especially the cavity length and sidewall thickness. The measured sensitivity of this strain sensor is as high as 56.69 pm/με, which is several times higher than that of most FPI strain sensors reported to date. This sensor also has a low-temperature sensitivity of 0.682 pm/°C, reducing the cross-sensitivity between tensile strain and temperature to 0.012 με/°C. Furthermore, such a sensor has the benefits of flexible design, simple fabrication, and high reproducibility, making it attractive for practical applications.
关键词： high sensitivity,fiber optic,Fabry-Perot interferometer,laser machining,strain sensor
更新于2025-09-23 15:21:01
-
Graphene induced sensitivity enhancement of thin-film coated long period fiber grating
摘要： In this work, the tuning property and sensitivity enhancement of the long period fiber grating (LPFG) coated with the higher refractive index film are demonstrated theoretically by integrating a monolayer graphene. The general variation rule of the mode characteristics and the resonance with the chemical potential of the graphene are explored. The polarization-independent transmission and sensing characteristics are obtained even though the optical property of the graphene is polarization-dependent. The results reveal that the sensing characteristics are significantly dependent on the tunable state of the graphene, which can be used to greatly optimize the sensing performance. By this approach, an ultrahigh sensitivity up to 28 337.5 nm/RIU is achieved, which is 2:57 times higher than that of the conventional LPFG without graphene. The sensitivity can be further optimized by integrating few-layer graphene. This tunable property at a wide range makes the graphene integrated LPFG devices without destroying the fiber integrity ideal for wide applications, such as biochemical sensing and optical modulation.
关键词： graphene,long period fiber grating,optical modulation,sensitivity enhancement,tunable property
更新于2025-09-23 15:21:01
-
Two-dimensional transition metal dichalcogenides mediated long range surface plasmon resonance biosensors
摘要： Two-dimensional transition metal dichalcogenides (TMDCs), as promising alternative plasmon supporting materials to graphene, exhibit potential applications in sensing. Here, we propose a TMDCs-mediated long range surface plasmon resonance (LRSPR) imaging biosensor, which shows tremendous improvements in both imaging sensitivity (> ×2) and detection accuracy (> ×10) as compared to conventional surface plasmon resonance (cSPR) biosensor. It is found that the imaging sensitivity of the LRSPR biosensor can be enhanced by the integration of TMDC layers, which is di?erent from the previously reported graphene-mediated cSPR imaging sensor whose imaging sensitivity decreases with the number of graphene layers. This imaging sensitivity enhancement e?ect for the TMDCs-mediated LRSPR sensor originates from the propagating nature of the LRSPR at both interfaces of sensing medium/gold and gold/cytop layer (with matching refractive index as sensing medium). By tuning the thickness of gold ?lm and cytop layer, it is possible to achieve optimized imaging sensitivity for LRSPR sensor with any known integrated number of TMDC layers and the analyte refractive index. The proposed TMDCs-mediated LRSPR imaging sensor could provide potential applications in chemical sensing and biosensing applications.
关键词： detection accuracy,biosensor,long range surface plasmon resonance,Two-dimensional transition metal dichalcogenides,imaging sensitivity
更新于2025-09-23 15:21:01