Phosphorus (P) and iron (Fe) are two essential mineral nutrients in plant growth. It is widely observed that interactions of P and Fe could influence their availability in soils and affect their homeostasis in plants, which has received significant attention in recent years. This review presents a summary of latest advances in the activation of insoluble Fe-P complexes by soil properties, microorganisms, and plants.
View Article and Find Full Text PDFThe link alignment is a challenge in underwater wireless optical communication (UWOC). This paper proposes a UWOC system adopting a fisheye lens with a field of view (FOV) of ±90° at the receiver to alleviate alignment requirement, and a mobile scanning device (MSD) is exploited to track the variation of the imaging position generated by the fisheye lens due to different incidence angles. In a 7-m tap water channel, a transmission with a data rate of 400 Mbps and an FOV of ±90° is realized with 16-quadrature amplitude modulating-orthogonal frequency division multiplexing (16-QAM-OFDM) modulation and orthogonal matching pursuit (OMP) channel estimation algorithm.
View Article and Find Full Text PDFIn this paper, an omnidirectional underwater wireless optical communication (UWOC) system is proposed, including six lens-free transceivers. An omnidirectional communication with a data rate of 5 Mbps in a 7-m underwater channel is experimentally demonstrated. The optical communication system is integrated into a self-designed robotic fish, and the signal is processed real-time through an integrated micro-control unit (MCU).
View Article and Find Full Text PDFA pulsed fiber master oscillator power amplifier (MOPA), which is combined with second harmonic generation (SHG) and modulated by directly changing the current of the low-power seed laser, is designed in this paper to overcome the 'green gap' of semiconductor lasers and the difficulty of obtaining high-power and wide-bandwidth driving circuits. To decrease the guard slot and increase the data rate of a high-order pulse position modulation (PPM) system, pre-pulse shaping (PPS) is utilized to decrease the fluctuation of pulse power, which is caused by the gain dynamics of multi-order amplification of the MOPA, from 55.6% to 27.
View Article and Find Full Text PDFSoybeans are a major crop that produce the best vegetable oil and protein for use in food and beverage products worldwide. However, one of the most well-known viral infections affecting soybeans is the Soybean Mosaic Virus (SMV), a member of the family. A crucial method for preventing SMV damage is the breeding of resistant soybean cultivars.
View Article and Find Full Text PDFChanges in soil aggregation with biochar amendment have been investigated extensively, but how biochar affects the chemical composition of organic carbon (C) and biological binding agents in aggregates and their linkage with soil aggregate stability remains unclear. Soil samples were collected in a rice paddy treated with 0 (C0, control), 10 t ha (C10), 20 t ha (C20) and 40 t ha (C40) biochar for twenty months. The amount and chemical composition of soil organic C (SOC), microbial abundances and glomalin-related soil protein (GRSP) were determined in bulk soil and four fractions: large macroaggregates (>2000 μm), small macroaggregates (250-2000 μm), microaggregates (53-250 μm), and silt + clay (<53 μm).
View Article and Find Full Text PDFSolar panels are being increasingly used as detectors in underwater wireless optical communication (UWOC) systems, as the large detection area can significantly simplify the link alignment. However, the greatest problem in such a scheme is the limited bandwidth of the solar panel, which was originally optimized for energy harvesting rather than communication. In this Letter, we propose series-connected solar arrays for high-speed underwater detection, by taking a deep dive into the fundamentals of the solar array.
View Article and Find Full Text PDFIn this paper, a quasi-omnidirectional transmitter is proposed and demonstrated for underwater wireless optical communication (UWOC) using the photoluminescence of perovskite quantum dots (QDs). The proposed transmitter, without complex driving circuits, is compact and reliable thanks to the lens-free design. The system performance is tested in a 50-m swimming pool with a water attenuation coefficient of 0.
View Article and Find Full Text PDFIn order to reduce turbulence-induced scintillation and deal with alignment problems, a 2×2 multiple-input multiple-output (MIMO) underwater wireless optical communication (UWOC) system is proposed and experimentally demonstrated. With help of the large divergence angle of light beams and large field of view (FOV) of the detectors, the effect of high-density air bubbles is greatly eliminated. Simulation and experimental results confirm that, in most intensity-modulation/direct-detection (IM/DD) MIMO-UWOC systems, the repetition coding (RC) scheme performs better than the space-time block coding (STBC) scheme.
View Article and Find Full Text PDFLinear and nonlinear impairments in underwater wireless optical communication (UWOC) systems caused by the limited bandwidth and nonlinearity of devices severely degrade the system performance. In this paper, we propose a sparse Volterra series model-based nonlinear post equalizer with greedy algorithms to mitigate the nonlinear impairments and the inter-symbol interference (ISI) in a UWOC system. A variable step size generalized orthogonal matching pursuit (VSgOMP) algorithm that combines generalized orthogonal matching pursuit (gOMP) and adaptive step size method is proposed and employed to compress the Volterra equalizer with low computational cost.
View Article and Find Full Text PDFIn this study, a quasi-omnidirectional underwater wireless optical communication (UWOC) system is implemented with a prismatic array consisting of three uniformly distributed high-power LED modules as the transmitter. Over a 10-m underwater channel in a 50-m standard swimming pool, a data rate of 22 Mbps is achieved without adopting any digital signal processing algorithm. With zero forcing (ZF) based frequency domain equalization (FDE) and a maximum ratio combining (MRC) algorithm, the maximum net data rates achieved are 69.
View Article and Find Full Text PDFWe experimentally demonstrate high-speed visible light communication (VLC) and high-quality solid-state lighting (SSL) using polymethyl-methacrylate-doped phosphor film based on cesium lead bromide quantum dot (CsPbBr-QD) and potassium fluorosilicate KSiF:Mn, which is excited by a blue gallium nitride laser diode. A 1.6 Gbps data rate is achieved by employing a non-return-to-zero on-off keying modulation scheme.
View Article and Find Full Text PDFFor some industrial underwater wireless optical communication (UWOC) applications, the transmission distance matters more than the communication rate. Attenuation length (AL) is an important distance indicator of UWOC system. In this paper, to the best of our knowledge, the spread spectrum (SS) technology is firstly applied in a UWOC system and the capability to extend transmission distance or AL is demonstrated.
View Article and Find Full Text PDFBy means of the serial nuclear transplantation technique, the authors obtained a nuclear transplant fish from subcultured cell originated from the blastula cells of the crucian carp (Carassius auratus Linnaeus). This nuclear transplant fish survived for three years, but its sexual glands were undifferentiated. The authors have also obtained a sexually mature adult fish from short-term cultured kidney cell nucleus of an adult crucian carp.
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