- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Polymer/Silica Hybrid Three-Dimension Integrated Multiplexer Based on MDM and WDM
摘要： In this paper, a polymer/silica hybrid three-dimension integrated multiplexer based on mode division multiplexing (MDM) and wavelength division multiplexing (WDM) is proposed. WDM is implemented on different layers by two multimode interference (MMI) couplers, and MDM is achieved by a three-dimension integrated asymmetric directional coupler. The coupling between the fundamental mode in the silica waveguide and the first-order mode in the polymer waveguide is realized by three-dimension integration of the upper polymer waveguide and the lower silica waveguide, and the WDM of 1310nm and 1550nm wavelength channels is realized by using structurally compact MMI coupler. The integration density of the chip is improved by multi-material hybrid integration and three-dimension integration, and the transmission capacity of the chip is increased by the multi-function integration of MDM and WDM.
关键词： MDM,hybrid integration,WDM,three-dimension integration
更新于2025-09-16 10:30:52
-
Engineering Multiphase Metal Halide Perovskites Thin Films for Stable and Efficient Solar Cells
摘要： The intrinsic instability of lead halide perovskite semiconductors in an ambient atmosphere is one of the most critical issues that impedes perovskite solar cell commercialization. To overcome it, the use of bulky organic spacers has emerged as a promising solution. The resulting perovskite thin films present complex morphologies, difficult to predict, which can directly affect the device efficiency. Here, by combining in-depth morphological and spectroscopic characterization, it is shown that both the ionic size and the relative concentration of the organic cation, drive the integration of bulky organic cations into the crystal unit cell and the thin film, inducing different perovskite phases and different vertical distribution, then causing a significant change in the final thin film morphology. Based on these studies, a fine-engineered perovskite is constructed by employing two different large cations, namely, ethyl ammonium and butyl ammonium. The first one takes part in the 3D perovskite phase formation, the second one works as a surface modifier by forming a passivating layer on top of the thin film. Together they lead to improved photovoltaic performance and device stability when tested in air under continuous illumination. These findings propose a general approach to achieve reliability in perovskite-based optoelectronic devices.
关键词： stability,solar cells,metal halide perovskites,bulky cations,mixed dimension
更新于2025-09-16 10:30:52
-
Cyclooctatetrathiophene-Cored Three-Dimensional Hole Transport Material Enabling Over 19% Efficiency of Perovskite Solar Cells
摘要： In this work, a rigid three-dimensional cyclooctatetrathiophene was the core component in the construction two hole transporting materials (HTMs), COTT-1 and COTT-2. Their photophysical, electrochemical and thermal properties were systematically investigated in a combination of experimental and simulation methods. COTT-1 and COTT-2 based perovskite solar cells (PSCs) were tested, exhibiting power conversion efficiency (PCE) of 8.4% and 17.7%, respectively, which are similar to Spiro-OMeTAD-based device (18.2%) under the same conditions. PCE was further increased to 19.2% using COTT-1 as an interfacial layer and COTT-2 as HTM. These phenomena were analyzed by means of photoluminescence (PL), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscope experiments (AFM), which demonstrated the potential of cyclooctatetrathiophene-cored hole transport material.
关键词： power conversion efficiency,interfacial modification,thiophene,perovskite solar cells,hole transport material,three dimension
更新于2025-09-16 10:30:52
-
Automatic road-marking detection and measurement from laser-scanning 3D profile data
摘要： Automatic road-marking detection and measurement have great significance for pavement maintenance and management. Laser-scanning 3D profile data provide a new way of road-marking detection and measurement with an elevation accuracy of about 0.25 mm. This paper presents an automatic road-marking detection and measurement method that uses laser scanning of 3D pavement data. The elevation characteristics and geometric statistics that characterize road markings have been fully analyzed using 3D data. The first step was to use a specially designed step-shaped operator to convolve profile data to identify the regions of suspected marking edges at the profile level, which helps reduce the influence of other pavement factors, including crosswise-slope information, cracks, and rutting. Next, by combining the geometric characteristics of the road-marking region and the continuity of the convolution features at image level, the regions of suspected 3D road markings were extracted. Third, a convolutional neural network was introduced to distinguish real-marking data more clearly. Finally, the three-dimension measurement information was extracted from the detected region and from elevation information. Road-marking recognition experiments were then conducted based on real measured 3D data. The detection accuracies were all greater than 90.8% for 4178 test samples from five road sections with different kinds of road markings. Furthermore, the repeatability of multiple measurement results for road-marking elevations from two selected road sections was about 95%, and the correlation of the obtained road-marking elevations with manually measured elevations was about 85.36% for 200 measurement points.
关键词： Road-marking detection,Laser scanning,Convolution,Three-dimension measurement information,Convolutional neural network
更新于2025-09-16 10:30:52
-
Characterization of spatiotemporal chaos in arrays of nonlinear plasmonic nanoparticles
摘要： We investigate spatiotemporal chaos dynamics in a finite nanoparticles array with Kerr-type nonlinear response, excited by an incident plane wave of varying intensity and tunable frequency close to the localized plasmon resonance of a single particle. Considering dipole-dipole coupling between the nanoparticles described by their polarizability, we compute the temporal evolution of the dipoles and numerically extract the Lyapunov spectra, allowing us to characterize different dynamical behaviors. Furthermore, we estimate the Kaplan-Yorke dimension that provides a measure of the strange attractor complexity. We show that time-modulated solutions which are generated at the onset of modulational instability experience secondary instabilities leading to a complex nonlinear dynamic. It is also shown that in the highly nonlinear regime, the spatiotemporal chaos is robust and exists in a large range of parameters that we have determined numerically.
关键词： nonlinear plasmonic nanoparticles,modulational instability,Lyapunov spectra,spatiotemporal chaos,Kaplan-Yorke dimension
更新于2025-09-11 14:15:04
-
Characterization and analysis on micro-hardness and microstructure evolution of brass subjected to laser shock peening
摘要： In view of the temperature distribution of the high-temperature geothermal tunnels, the surrounding rock temperature was divided into four grades (40 (cid:1)C, 60 (cid:1)C, 80 (cid:1)C and 100 (cid:1)C) to simulate the hot-dry environment. Using the standard curing environment as a reference condition, the mechanical properties and pore structure characteristics of concrete for shotcrete use under hot-dry environments at different temperatures were studied by mechanical and mercury intrusion porosimetry (MIP) tests. Fractal dimension of pore structure was calculated through the fractal model based on thermodynamic method. Bivariate correlation analysis was conducted on the curing temperature and the pore structure parameters. The results show that the 40 (cid:1)C hot-dry environment is conducive to enhance the mechanical properties of concrete and optimize its pore structure at the age of 1d. However, the hot-dry environments after 7 days will deteriorate the mechanical properties and pore structure of concrete, and the higher the temperature, the more obvious the deterioration. There is a significant correlation between curing temperature and porosity of capillary pores, median pore diameter, average pore diameter and fractal dimension.
关键词： Pore structure,Surrounding rock temperature,Mechanical property,Fractal dimension,Concrete for shotcrete use,High-temperature geothermal tunnel,Hot-dry environment
更新于2025-09-11 14:15:04
-
Facile green and one-pot synthesis of purple perilla derived carbon quantum dot as a fluorescent sensor for silver ion
摘要： Coalbed methane (CBM) reservoir pore structure is extremely complex and heterogeneous. With the fractal theory, the geometric and structural characteristics of the pore structure could be quanti?ed. However, few studies have aimed to understand the fractal features of compositional-based macrolithotypes (bright, semi-bright, semi-dull, and dull coals). In this work, samples from the Hancheng area, in the southeastern Ordos Basin, China, were collected to investigate the fractal features of pore structures for macrolithotypes and calculate fractal dimensions (Da1 and Da2 for adsorption pores; Ds1 and Ds2 for seepage pores) based on low temperature N2 adsorption and mercury intrusion data, respectively. Meanwhile, the impact of the fractal dimensions on the gas adsorption capacity and the seepage ability were discussed. The results demonstrate that when bright coal turns into dull coal, the vitrinite content, helium permeability, and gas adsorption capacity gradually decrease, while the coal density, mineral content, and ash yield increase. Since the Da1 and Ds1 either deviate from the natural fractal dimension (2 < D < 3) or have a poor correlation with macrolithotypes, Da2 and Ds2 are regarded as the adsorption and seepage pore fractal dimensions, respectively. Of all the coal macrolithotypes, bright coal has the smallest BET speci?c surface area and micropore proportion, which results in the smallest fractal dimension Da2, while for the dull coal, this is just the contrary; due to the higher mineral content, a higher Da2 of the dull coal indicates a more complicated adsorption pore structure, and the coal with a larger Langmuir volume has a smaller Da2. For the seepage pores, when the bright coal turns into dull coal, the macropore proportion gradually decreases, but the pore proportion tends toward equilibrium, and the mercury withdrawal e?ciency increases; the dull coal has a larger Ds2, indicating a more complex seepage pore structure than that in the bright coal. Due to the decreasing macropore proportion and mineral ?lling, Ds2 demonstrates an obvious negative correlation with the helium permeability and macropore proportion.
关键词： Adsorption pore,Pore structure,Seepage pore,Fractal dimension,Coal macrolithotype
更新于2025-09-11 14:15:04
-
Defect induced thermal-plasma coupling damage in optical films under nanosecond pulse laser irradiation
摘要： Ten prestressed concrete beams were designed and manufactured, which were preloaded with 40% and 60% ultimate load to crack. Then the beams were reinforced by CFRP and immersed in chloride condition for 120 days. After that, a four-point bending test was performed. Based on the statistics and fractal theories, the cracking mechanism, distribution and shapes of cracks in mid span were researched, considering the initial cracks, CFRP reinforcement and chloride corrosion. The test results demonstrate that CFRP has a restraining effect on the cracks, and the effect decreases with the increases of heights. The crack widths conform to normal distribution, and the dispersion coefficient, average widths and characteristic widths decrease with the increase of the heights, and the three parameters of CFRP reinforced beams at the same heights are all smaller than those of unreinforced beams. The fractal dimensions of cracks in unreinforced beams and CFRP reinforced beams increase linearly and exponentially with load steps, respectively. CFRP reinforcement and Chloride corrosion makes the fractal dimension increase, respectively. The corrosion effect of chloride can be weakened by CFRP. Therefore, the fractal dimensions of beam cracks can be used to evaluate the damage caused by several coupled load conditions.
关键词： chloride corrosion,cracks,fractal dimension,prestressed concrete beams,CFRP
更新于2025-09-11 14:15:04
-
Comprehensive modeling of the lithographic errors in laser direct write
摘要： Patterns written by laser direct write have a critical dimension (CD) bias dependence on the dose similar to other direct write methods, such as electron beam lithography, which can be explained by the exposure intensity distribution (EID) of the laser beam. In this study, a comprehensive model based on the EID is proposed to understand the pattern CD bias dependence on the dose, which is known as the exposure latitude. This model was supported by the results of the exposure tests on MicroChem S1800 resist on an Si wafer using the Heidelberg DWL66+ laser writer. The exposure latitudes of the patterns at both micrometer and submicrometer scale were measured. At the micrometer scale, the exposure latitudes were found to have no measurable dependence on the pattern size and the local pattern density. This conclusion does not hold at the submicrometer scale where the length scale is comparable to the width of the laser beam. This study proposes a way to convert the experimental exposure latitude data into the EID functions and fit these functions by assuming a Gaussian laser beam intensity distribution. All empirical observations are found to agree with the predictions made by the EID model. The authors also show that this model can help achieve dimensional accuracy, especially when there is a change in the exposure process. Moreover, it can be used to analyze and minimize the CD inconsistency between different runs found in the experiments. To reduce such inconsistency, overexposing combined with a negative bias applied to the pattern is suggested.
关键词： lithographic errors,exposure latitude,exposure intensity distribution,laser direct write,critical dimension bias
更新于2025-09-11 14:15:04
-
Dynamic proportional-fuzzy grip control for?robot arm by two-dimensional vision sensing method
摘要： In this study, a four-degree of freedom (4-DOF) robot arm uses an innovative two-dimensional vision sensing method to grip a moving target on a moving platform. This study utilizes forward and inverse kinematics to establish a dynamic model of the 4-DOF robot arm. A computer as a controller and a single charge-coupled device (CCD) calculates the two-dimensional vision sensing method and sends commands to an Arduino Uno microcontroller to drive the robot arm. According to simulation results of transient and steady states in MATLAB SimMechanics, the response of the dynamic proportional-fuzzy controller is better than the response of proportional–integral–derivative controller. To demonstrate a precise control of the point-contact grip, this study utilizes a ping pong ball as a target on a moving platform. Using the dynamic proportional-fuzzy controller based on the two-dimensional vision sensing method, the 4-DOF robot arm can position, grip, and carry a moving ping pong ball to a designated place in three-dimensional space, which breaks through the previous two-dimensional limitation using a single CCD. This breakthrough can reduce the weight and cost of the robot arm. Therefore, this study aims to utilize the technology to grip moving targets on a moving platform for manpower cost reduction in the industry or agriculture domain in the future.
关键词： dynamic proportional-fuzzy controller,two-dimension limitation using a single CCD,Four-degree of freedom robot arm,forward and inverse kinematics,two-dimensional vision sensing method
更新于2025-09-11 14:15:04