- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effect of Light Intensity on Rooting and Growth of Hydroponic Strawberry Runner Plants in a LED Plant Factory
摘要： To rapidly produce strawberry (Fragaria × ananassa Duch. cv. Benihoppe) transplants from cuttings, suitable light intensities for unrooted runner plants at the rooting stage and rooted runner plants at the seedling stage were determined in a plant factory under LED lighting. At the rooting stage, unrooted runner plants at the 3-leaf stage were hydroponically rooted for 6 days under light intensity of 30, 90, 150, and 210 μmol m?2 s?1, respectively. At the seedling stage, rooted runner plants were hydroponically grown for 18 days under light intensity of 90, 180, 270, and 360 μmol m?2 s?1, respectively. The tube LED lights consisting of white and red LED chips were used as sole light source, and photoperiod was controlled as 16 h d?1. The results showed that the maximum root number (7.7) and longest root length (14.8 cm) of the runner plants were found under 90 μmol m?2 s?1 at the rooting stage. Photosynthetic activity in runner plant leaves under 90 μmol m?2 s?1 were higher than that under 30, 150, and 210 μmol m?2 s?1. Higher light intensity at the range of 90–270 μmol m?2 s?1 increased the stomatal conductance of newly formed leaves of rooted runner plants, thus improving the net photosynthetic rate and growth of rooted runner plants at the seedling stage. The crown diameter, shoot and root dry weights, and root to shoot ratio of rooted runner plants increased by 9.7%, 38.8%, 106.1%, and 48.7%, respectively, when the light intensity increased from 90 to 270 μmol m?2 s?1. However, there was no further improvement of runner plant growth under 360 μmol m?2 s?1. Furthermore, no significant difference of increased dry biomass per mole of photons delivered was found between 180 and 270 μmol m?2 s?1. In consideration of transplant quality and economic balance, light intensity of 90 μmol m?2 s?1 at the rooting stage and 270 μmol m?2 s?1 at the seedling stage were suggested for rapidly producing hydroponic strawberry transplants based on unrooted runner plants in the LED plant factory.
关键词： photosynthetic activity,rooting stage,seedling stage,cutting,strawberry transplant,daily light integral,vegetative propagation
更新于2025-09-12 10:27:22
-
Broadband Determination of the Even- and Odd-Mode Propagation Constants of Coupled Lines Based on Two-Port Measurements
摘要： We describe a method for the broadband measurement of the even- and odd-mode propagation constants of symmetrical coupled transmission lines. The main advantage of the method, its simplicity, lies in the lack of need for four-port measurements. Only two-port measurements are required, and thus just a two-port vector network analyzer (VNA). The accuracy of the results can be increased at the cost of a higher number of measured coupled-line lengths. The new approach has been successfully applied for the determination of coupled microstrip lines in the 2- to 20-GHz frequency band in both simulated and experimental cases. A brief discussion about the repeatability of the microstrip launcher and the adverse effects of radiation is included.
关键词： coupled microstrip lines,transmission line measurements,characterization,Broadband measurements,multiconductor transmission lines,propagation constant
更新于2025-09-12 10:27:22
-
[IEEE OCEANS 2019 - Marseille - Marseille, France (2019.6.17-2019.6.20)] OCEANS 2019 - Marseille - Multi-laser Transmissometer for Ocean Optical Classification and Biofouling Detection
摘要： This research and development effort designs and tests new multi-laser transmissometer algorithms and hardware for ocean optical classification and autonomous biofouling detection. The system expands the collection of inherent optical properties and enables in-situ wavelength optimization for future optical communication links. Undersea testing succeeded and was contingent on several accomplishments, including developing robust algorithms, integrating opto-electronics within a custom chassis, and engineering a handheld-sized pressure vessel suitable for diverse field experimentation. The project verifies the feasibility of key enablers—autonomy, environmental classification, biofouling detection, and laser propagation—for remote undersea platforms with low size, weight, and power.
关键词： sensing,propagation,lasers,autonomy,underwater,undersea,oceanography,optimization,free space optical communication
更新于2025-09-12 10:27:22
-
Design and Simulation of the Fourier Transform Beam Propagation Method in Different Optical Waveguides
摘要： Fundamentals of optical waveguides is a needed resource for any researcher, concerned in optics and communications engineering. Interested by designing or actively running with optical gadgets have to have a company hold close of the standards of light wave propagation. This paper presents an FFT Beam Propagation Method Models for optical waveguides. The technique is based on the use of the Propagation of a Gaussian pulse by a waveguide with a rectangular, triangular optical waveguides and free space the cases of straight and bent optical waveguides are successively considered.
关键词： Gaussian pulse,free space,triangular optical waveguides,optical waveguides,FFT Beam Propagation Method,rectangular
更新于2025-09-12 10:27:22
-
Revisiting the calculation of performance margins in monitoring-enabled optical networks
摘要： In the context of future intelligent optical networks, dedicated learning techniques can be employed to monitor physical system parameters with a guaranteed accuracy. In this work, we investigate a method that establishes the link between input parameter uncertainties and the overall performance uncertainty. To this end, neglecting stochastic effects and focusing on the input parameters of a simplified Gaussian noise model version, we employ uncertainty propagation to evaluate the overall performance uncertainty from input parameter uncertainties, and we propose a simple way to link performance uncertainty to margins. With this method, as opposed to direct performance monitoring, it is possible to trace, in a predictable way, the path from the cause (input parameter uncertainties) to the effect (performance uncertainty) and to the additional network-level consequences (performance margins). We briefly review methods used in the literature to set margins in classical systems, and we show how all methods can be unified by means of the correlation between input parameters. By quantifying the impact of input parameter correlations, we further discuss the margins that can be saved if input parameters are partially correlated or uncorrelated, compared to a scenario in which parameters are fully correlated. We finally illustrate the separate impact of each parameter on performance uncertainty, and we briefly discuss their order of importance as a function of the system operating regime and propagated distance.
关键词： optical networks,performance margins,deterministic margins,uncertainty propagation,Gaussian noise model
更新于2025-09-12 10:27:22
-
Nonlinear Fiber Optics || Group-velocity dispersion
摘要： The preceding chapter showed how the combined effects of group-velocity dispersion (GVD) and self-phase modulation (SPM) on optical pulses propagating inside a fiber can be studied by solving a pulse-propagation equation. Before considering the general case, it is instructive to study the effects of GVD alone. This chapter considers the pulse-propagation problem by treating fibers as a linear optical medium. In Section 3.1 we discuss the conditions under which the GVD effects dominate over the nonlinear effects by introducing two length scales associated with GVD and SPM. Dispersion-induced broadening of optical pulses is considered in Section 3.2 for several specific pulse shapes, including Gaussian and 'sech' pulses. The effects of initial frequency chirping are also discussed in this section. Section 3.3 is devoted to the effects of third-order dispersion on pulse broadening. An analytic theory capable of predicting dispersive broadening for pulses of arbitrary shapes is also given in this section. We discuss in Section 3.4 how the GVD can limit the performance of optical communication systems and how the technique of dispersion management can be used to combat such limitations.
关键词： dispersion management,dispersion-induced broadening,sech pulses,Group-velocity dispersion,GVD,optical pulses,third-order dispersion,SPM,Gaussian pulses,self-phase modulation,fiber propagation,frequency chirping
更新于2025-09-12 10:27:22
-
Harmonic Mode-Locking in Bidirectional Domain-Wall Soliton Fiber Lasers
摘要： We report on the first experimental observation of passively harmonic mode-locking (HML) in a bidirectional domain-wall dark-soliton fiber laser. The domain-wall solitons (DWSs) are characterized, in which, the strong coupling between the two directions takes great responsibility for the generation. By appropriately altering the polarization state in the cavity, the stable fundamental domain-wall solitons and HML states could be obtained and switched with increasing the pump power. In our experiment, the repetition rate can be tunable from the fundamental mode locking of 2.96 MHz up to eighth-order HML of 23.68 MHz when the pump power is increased from 120 to 542.5 mW. Importantly, this HML operation of dark-pulse DWSs confirms that the DWSs are the intrinsic feature of the mode-locked lasers, as well as the conventional bright solitons. This work could provide a new perspective to the understanding of the formation and transformation of dark solitons, which may also find great potential applications in fiber sensing and future optical communication systems.
关键词： lasers and laser optics,mode-locked lasers,ultrafast photonics,pulse propagation and temporal solitons
更新于2025-09-12 10:27:22
-
Dual-wavelength dissipative solitons in an anomalous-dispersion-cavity fiber laser
摘要： We report on the experimental observation of dual-wavelength dissipative soliton operation of a fiber laser with net anomalous cavity dispersion. Different from the dual- or multi-wavelength soliton operation of fiber lasers where mode locking is used to initiate soliton formation, no mode locking occurs in our fiber laser. Instead, soliton formation is through the dissipative mechanism caused by the effective gain bandwidth limitation. Either dual-wavelength scalar, or vector, or induced dissipative solitons are experimentally obtained. Their robustness is experimentally confirmed.
关键词： fiber lasers,pulse propagation and temporal solitons,nonlinear fiber optics
更新于2025-09-12 10:27:22
-
Pulse-Propagation Modeling and Experiment for Femtosecond-Laser Writing of Waveguide in Nd:YAG
摘要： In this work, unidirectional pulse propagation equation (UPPE) modeling is performed to study the nonlinear laser-mater interaction in silicon and Nd:Y3Al5O12 (Nd:YAG) crystals. The simulation results are validated with reported experimental results for silicon and applied to Nd:YAG crystals with experimental validation. Stress-induced waveguides are written in Nd:YAG crystals using 515 nm, 300 fs pulses at a 1 kHz repetition rate. Waveguides having a mean propagation loss of 0.21 ± 0.06 dB/cm are obtained, which is lower than the previous reported values for Type-II waveguides written in Nd:YAG crystals. The modeling and experimental results consistently show that the modi?cation (waveguide track) depth increases with input energy. A detailed analysis is presented to control the modal properties of the waveguide in the context of UPPE simulation.
关键词： stress-induced waveguide writing,nonlinear pulse propagation,femtosecond laser writing,Nd:YAG crystal
更新于2025-09-12 10:27:22
-
Scintillation experiments with non-uniformly and uniformly correlated spatially partially coherent laser beams propagating underwater
摘要： We report on experiments where non-uniformly correlated (NUC), Gaussian Schell (GSM) and Multi-Gaussian Schell (MGSM) model spatially partially coherent laser beams were propagated underwater. Two scenarios were explored: still water and mechanically agitated water. The main objective of our study was the experimental comparison of the scintillation performance among beams with different correlation functions. The results show generally increased absolute values of scintillation index for NUC beams as compared with GSM and MGSM beams. We hypothesized that this effect is related to the method of NUC beams generation. It should be noted, that the presented results document only the given experimental scenarios and show the relative comparison between GSM, MGSM and NUC beams with Gaussian used as a turbulence level benchmark. Further investigation is necessary to broaden the scope of our explorations of the propagation of uniformly correlated spatially partially coherent as well as non-uniformly correlated beam classes.
关键词： multi-Gaussian Schell model beam,Non-uniformly correlated,partial spatial coherence,scintillation,experimental validation,underwater laser propagation
更新于2025-09-12 10:27:22