- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Modeling the influence of the optical fiber strain on the readiness performance of fiber-optic communication lines
摘要： A mathematical model for determining the readiness performance of the fiber-optic communication lines depending on the degree of optical fiber strain with different methods of influence. The model is based on the theory of Markov chains. The adequacy of the model is achieved by the false positive and false negative errors. The application of the developed model enables us to determine the allowable maintenance interval for the fiber-optic communication lines.
关键词： readiness performance,optical fiber strain,current time,real time,mathematical model,fiber-optic communication line,tensile load
更新于2025-09-16 10:30:52
-
Nonlinear Oscillatory Shear Tests in Viscoelastic Holography
摘要： We provide the first characterization of the nonlinear and time dependent rheologic response of viscoelastic bottom-up holographic models. More precisely, we perform oscillatory shear tests in holographic massive gravity theories with finite elastic response, focusing on the large amplitude oscillatory shear (LAOS) regime. The characterization of these systems is done using several techniques: (i) the Lissajous figures, (ii) the Fourier analysis of the stress signal, (iii) the Pipkin diagram and (iv) the dependence of the storage and loss moduli on the amplitude of the applied strain. We find substantial evidence for a strong strain stiffening mechanism, typical of hyperelastic materials such as rubbers and complex polymers. This indicates that the holographic models considered are not a good description for rigid metals, where strain stiffening is not commonly observed. Additionally, a crossover between a viscoelastic liquid regime at small graviton mass (compared to the temperature scale), and a viscoelastic solid regime at large values is observed. Finally, we discuss the relevance of our results for soft matter and for the understanding of the widely used homogeneous holographic models with broken translations.
关键词： LAOS regime,viscoelastic holography,strain stiffening,nonlinear oscillatory shear tests,viscoelastic materials
更新于2025-09-16 10:30:52
-
Measuring the heterogeneity of cement paste by truly distributed optical fiber sensors
摘要： In this study, a home-built Rayleigh scattering based optical frequency domain reflectometry (OFDR) technique is used for the measurement of strain distribution in a loaded cement paste. The system offers a spatially-continuous strain measurement on an optical fiber with a spatial resolution of 1 cm, dynamic range of 1 km, measurement accuracy of ±2 microstrain, and an update rate of 10 Hz. The feasibility and performance of this technique for detection of uneven strain distribution are studied and evaluated. The distributed optical fiber sensors are embedded in a cement paste cantilever. A controlled deflection is applied at the free end of it, and the strain is measured. The results are compared with the values obtained from theoretical analysis using Euler-Bernoulli beam theory and a finite element simulation. The comparison shows a reasonable consistence in overall deformation, demonstrating that the proposed technique can be used for real time strain monitoring in cement based materials; while this technique can reflect the uneven distribution of local strains due to the material heterogeneity with a controllable, high spatial resolution.
关键词： Cement paste,Distributed sensing,Optical fiber,Uneven strain distribution
更新于2025-09-16 10:30:52
-
[IEEE 2019 2nd International Colloquium on Smart Grid Metrology (SMAGRIMET) - Split, Croatia (2019.4.9-2019.4.12)] 2019 2nd International Colloquium on Smart Grid Metrology (SMAGRIMET) - Fiber Optic Sensor Cable Based on Hollow Capillary Tube with Three Tightly Encapsulated Optical Fibers
摘要： Fiber optic sensor cable technology is relatively new field that combines a set of scientific and technical disciplines in a special way in order to meet industrial standards. In this paper we discuss one particular design for multipurpose and configuration multivalent optical fiber sensing. It has the potential to integrate more detection and measurement techniques in one cable body and this, in turn, largely contributes to installation cost optimization and directly impacts investment plans and industrial success. The article presents also a unique high-pressure high temperature lab facility conceptualized and constructed for testing and evaluation of this and similar optical fiber sensor cables.
关键词： fiber optic measurements,OFDR,acoustic sensors,BOTDA,BOTDR,DAS,Brillouin effect,optical fiber,pressure sensors,fully distributed optical fiber sensor,monitoring systems,strain sensors,temperature sensors,OTDR
更新于2025-09-16 10:30:52
-
Theoretical Study of GaN/BP van der Waals Nanocomposites with Strain-Enhanced Electronic and Optical Properties for Optoelectronic Applications
摘要： Construction of van der Waals (vdW) nanocomposites can advance two-dimensional (2D) materials with desired properties and significantly widen their applications. Based on first-principles calculations, we verify that a gallium nitride/boron phosphide (GaN/BP) vdW nanocomposite is a direct-gap semiconductor with type-I band alignment. The nanocomposite shows significant optical properties in the visible and near-ultraviolet regions. Additionally, the bandgap, band edge positions, and optical absorption of the GaN/BP nanocomposite can be tuned by in-plane biaxial strains. A biaxial tensile strain with a strength of 3% can induce the type-II band alignment in the GaN/BP nanocomposite, which results in effective separation of the photo-generated charge carriers. Meanwhile, the application of biaxial strain can also significantly enhance the optical absorption of the GaN/BP nanocomposite in the near-infrared and visible regions. Furthermore, we show that the adjustment of interlayer coupling is also an effective way to modulate the electronic and optical properties of the GaN/BP nanocomposite. Our studies reveal the potential application of the GaN/BP nanocomposite in optoelectronic devices.
关键词： first-principles calculations,optical absorption,strain engineering,band structure,GaN/BP nanocomposite
更新于2025-09-16 10:30:52
-
Recrystallization and activation of ultra-high-dose phosphorus-implanted silicon using multi-pulse nanosecond laser annealing
摘要： Highly phosphorus-doped silicon source/drains are investigated to improve the performance of N-type metal-oxide-semiconductor field-effect transistors by decreasing their resistance and imparting strain to their channels. To find effective high temperature annealing for the activation of phosphorus in the source/drains, we apply single- and multi-pulse nanosecond laser annealing on highly phosphorus-doped silicon. The microstructure, strain, and electrical properties of highly phosphorus-doped silicon before and after laser annealing are analyzed. Our results demonstrate that the defects in both the recrystallized silicon and the end of range are decreased with 600 mJ cm?2 10-pulse annealing while considerable increase in phosphorus activation is achieved.
关键词： nanosecond laser annealing,strain engineering,activation,phosphorus-doped silicon,recrystallization
更新于2025-09-16 10:30:52
-
Demonstration of low forward voltage InGaN-based red LEDs
摘要： Here we report InGaN-based red light-emitting diodes (LEDs) grown on (201) β-Ga2O3 substrates. AlN/AlGaN strain-compensating layers and hybrid multiple-quantum-well structures were employed to improve the crystalline-quality of the InGaN active region. A bare LED showed that peak wavelength, light output power, and external quantum efficiency were 665 nm, 0.07 mW, and 0.19% at 20 mA, respectively. As its forward voltage was 2.45 V at 20 mA, the wall-plug efficiency was 0.14%. The characteristic temperature of the LEDs was 222 K at 100 mA evaluated from the temperature dependence of electroluminescence.
关键词： InGaN,β-Ga2O3 substrates,red LEDs,multiple-quantum-well structures,strain-compensating layers
更新于2025-09-16 10:30:52
-
Effect of Coupled Quantum-Dot Insertion on the Radiative Recombination Probability of Wurtzite InGaN/GaN Quantum Dots
摘要： Light emission charactersitcs of single and coupled wurtzite (WZ) InGaN/GaN quantum-dot (QD) structures were investigated by using an e?ective mass theory. Strain components in the well of the coupled QD are found to be smaller than those in the well of the single QD structure. In particular, the reduction e?ect in (cid:2)zz is dominant and, as a result, the polarization component Izz for the strain tensor (cid:2)zz is largely reduced for the coupled QD. The coupled QD structure shows much larger peak intensity than the single QD structure because the interband transition probability between electrons and holes is enhanced owing to the reduced internal ?eld.
关键词： InGaN,GaN,Polarization potential,Strain,Quantum dot
更新于2025-09-16 10:30:52
-
Performance of Distributed Optical Fiber Sensors (DOFS) and Digital Image Correlation (DIC) in the monitoring of RC structures
摘要： Distributed Optical Fiber Sensors (DOFS) are strain measuring tools whose potential related to the civil engineering field has been discovered in the latest years only. A unique utility lies in the possibility of bonding these extremely thin sensors to steel reinforcement bars which will later be embedded in concrete elements (RC) in order to monitor its mechanical strains. The present paper presents the results of an experimental campaign that saw the tensing of two RC tensile members (ties) with DOFS-instrumented steel rebars providing strain readings every 7.5mm. Their cracking behavior allows to gain insight on the steel rebar’s strain profile when surrounded by cracking concrete. The described results are novel as measurements that are accurate, completely distributed, experimentally extracted, both before and after concrete cracking, have been impossible up until now. The internal strain measurements are additionally integrated with an external Digital Image Correlation (DIC) monitoring which provides data on the displacements and strains of the members’ surfaces. The present research represents the beginning of an in-depth experimental campaign aimed at providing reinforcement strain data for multiple loaded RC ties encompassing different geometrical features (concrete cover, reinforcement ratio, bar diameter).
关键词： strain monitoring,concrete cracking,Digital Image Correlation (DIC),Distributed Optical Fiber Sensors (DOFS),RC structures
更新于2025-09-16 10:30:52
-
Wholea??field strain analysis and strength prediction of fiber laser machined CFRP laminate at elevated temperature
摘要： High power fiber laser was proved to be feasible to cut carbon fiber reinforced plastic (CFRP) laminate with high efficiency, while the machined quality on mechanical performance was not fully understood. This paper studied the effect of high temperature up to 220°C on tensile strength degradation and strain distribution of unidirectional CFRP laminate with open hole machined with fiber laser. Differential scanning calorimetry (DSC) was firstly employed to determine the glass transition temperature (Tg) of polymer-matrix composite. Digital image correlation technique was applied to evaluate whole-field strain distribution and crack propagation/evolution of CFRP laminate featured with open hole under tensile loading. Results showed that the tensile strength of laser machined CFRP laminate degraded significantly during working in high temperature above 100°C. The value of strains distributed around center hole was highly related to the elevated temperature and applied load levels. Splitting was the prevalent failure mode of CFRP laminate under elevated temperature up to 180°C. Finally, semi-empirical model was developed for evaluating tensile performance of laser machined CFRP laminate at elevated temperature based on regression analysis.
关键词： digital image correlation,laser cutting,mechanical behavior,strain distribution,CFRP
更新于2025-09-16 10:30:52