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Optical interferometry is a promising alternative for acoustic detection as it records the changes of interference patterns. Apart from interferometric sensor heads, readout systems also play a crucial role in sensing performance. Here, inspired by the soliton molecule vibrations in ultrafast lasers, we introduce an efficient real-time spectral interferometry (RSI) approach to read out the Fabry–Pérot interferometer (FPI) for acoustic detection. Broadband pulses, emitted from an ultrafast fiber laser, are launched into the FPI sensor. Pseudo dual-pulse molecule is constructed by virtue of the equivalent two-beam interference of the FPI and modulated by the diaphragm transducer. The acoustic driven "molecular vibration" conforms to the sound applied on the metal diaphragm. Hence, the acoustic signals can be directly recorded by the successive dual-pulse spectral interferograms, imaged as a spectral encoded "soundtrack." We experimentally achieve the real-time characterization of both the audible and ultra sounds by retrieving the relative phase evolutions with a phase resolution of 37.6 mrad and preliminarily verifying the feasibility of the RSI in acoustic detection. This approach to wideband acoustic detection highlights an advanced application of ultrafast laser sources and paves an efficient way for interrogating the interferometric fiber sensors. [ABSTRACT FROM AUTHOR]

Manglietiastrum sinicum Y.W. Law is a critically endangered species with great ornamental and commercial value, which urgently requires protection. We tested different combinations of basal media and plant growth regulators to determine (i) the optimal conditions for bud induction and proliferation of explants and (ii) optimal rooting conditions. RAPD- and ISSR-PCR were used to assess the genetic fidelity of regenerated plantlets. Murashige and Skoog medium (MS) supplemented with 0.5 mg/L 6-benzyladenine (BA) and 0.05 mg/L indole-3-butyric acid (IBA) is the optimal medium for bud induction (100% induction). MSM medium (a special basal medium for M. sinicum) was more suitable for the efficient proliferation and rooting of M. sinicum. Maximum bud proliferation rate (446.20%) was obtained on MSM, with 0.4 mg/L BA, 0.5 mg/L kinetin, and 0.06 mg/L IBA, while maximum root induction rate (88.89%) was obtained on MSM supplemented with 0.4 mg/L 1-naphthylacetic acid and 1.0 mg/L IBA with a 7-day initial darkness treatment. The rooted plantlets were transferred to a substrate containing peat soil, perlite, coconut chaff, and bark (volume ratio 2:1:1:1), with a resulting survival rate of 92.2%. RAPD and ISSR markers confirmed the genetic uniformity and stability of regenerated plants. [ABSTRACT FROM AUTHOR]

Based on reasonable simplifications of a two‐dimensional (2D) energy equation, a basic heat transfer equation in 1D form is obtained for the hot crude oil transportation in a long‐buried pipeline. To enclose the heat transfer equation, the overall heat transfer coefficient and the numerical simulation of temperature fields of pipe wall and soil are introduced, and they together with the basic heat transfer equation constitute 1D and cross‐dimensional heat transfer models of crude oil transportation, respectively. Some numerical procedures, including grid generation, partial differential equation discretization, and algebraic equation solution, are combined to solve the two heat transfer models. Based on the designed cases with different pipeline parameters, the relative deviation between the numerical results from the two heat transfer models does not exceed 1%, and the two heat transfer models agree well. Furthermore, the nonuniform natural soil temperature field is designed, and its influence on the oil temperature and the deviation of the 1D heat transfer model is investigated. Under the condition of the nonuniform natural soil temperature field, the atmospheric temperature as the ambient temperature in the 1D heat transfer model causes an apparent deviation, whereas the soil temperature at the buried depth of the pipeline in the natural soil temperature field as the ambient temperature does not. This study can provide a reference for the reasonable selection and use of the heat transfer models of the buried hot oil pipeline. [ABSTRACT FROM AUTHOR]

To study the electromagnetic radiation of the lithosphere associated with seismic waves, we used the recordings of the natural electromagnetic radiation obtained under conditions of weak industrial noise and a high level of microseismicity in the ELF-VLF wave bands. It is shown that these data contain information about the surface waves of the Earth’s crust and are accompanied by a frequency close to the first harmonic of the Schumann resonance. The distribution of spikes over thresholds is obtained, which can be indicators of the activity in the processes of the Earth’s crust. The averaged form of the spikes for different components of the electromagnetic field is obtained. Attention is drawn to the differences in the various components of the electromagnetic field and their diurnal differences are analyzed. The possibility of using the approach to predict the short-term movement of the Earth’s crust is considered.

The self-assembly of optical solitons propagating in nonlinear dissipative systems spreads the concept of soliton molecules. Assisted with the real-time spectral interferometry, plentiful internal dynamics has been probed within the multi-pulse patterns, emphasizing the striking analogies with the matter molecules. Therefrom, these particle-like behaviors would yield more intriguing landscapes toward the extended degrees of freedom considering increased constituents. Here, we transfer the concept of "isomer" to the experimental investigation on the unexplored isomeric dynamics of soliton molecules in parallel. Particularly, two isomers for soliton triplets and four isomers for soliton quadruplets are captured under different self-assembled forms, within each of which the binding separations and relative phases of the constituents are governed by mutual soliton interactions. With the diverse separation-phase evolving trajectories mapped in the interaction plane, detailed insights into the temporal distribution and the transient dynamics are displayed with respect to a panorama of the isomeric dynamics. The perspective of optical isomers shed new light on the analogy with matter molecules, and the underlying isomeric dynamics may stimulate the artificial manipulation of various soliton molecules for ultrafast applications. [ABSTRACT FROM AUTHOR]

Coronavirus 2019 (COVID‐19) has caused violent fluctuation in stock markets, and led to heated discussion in stock forums. The rise and fall of any specific stock is influenced by many other stocks and emotions expressed in forum discussions. Considering the transmission effect of emotions, we propose a new Textual Multiple Auto Regressive Moving Average (TM‐ARMA) model to study the impact of COVID‐19 on the Chinese stock market. The TM‐ARMA model contains a new cross‐textual term and a new cross‐auto regressive (AR) term that measure the cross impacts of textual emotions and price fluctuations, respectively, and the adjacent matrix which measures the relationships among stocks is updated dynamically. We compute the textual sentiment scores by an emotion dictionary‐based method, and estimate the parameter matrices by a maximum likelihood method. Our dataset includes the textual posts from the Eastmoney Stock Forum and the price data for the constituent stocks of the FTSE China A50 Index. We conduct a sliding‐window online forecast approach to simulate the real‐trading situations. The results show that TM‐ARMA performs very well even after the attack of COVID‐19. [ABSTRACT FROM AUTHOR]