Strong Exciton-Phonon Coupling as a Fingerprint of Magnetic Ordering in van der Waals Layered CrSBr

The layered, air-stable van der Waals antiferromagnetic compound CrSBr exhibits pronounced coupling between its optical, electronic, and magnetic properties. As an example, exciton dynamics can be significantly influenced by lattice vibrations through exciton-phonon coupling. Using low-temperature photoluminescence spectroscopy, we demonstrate the effective coupling between excitons and phonons in nanometer-thick CrSBr. By careful analysis, we identify that the satellite peaks predominantly arise from the interaction between the exciton and an optical phonon with a frequency of 118 cm-1 (~14.6 meV) due to the out-of-plane vibration of Br atoms. Power-dependent and temperature-dependent photoluminescence measurements support exciton-phonon coupling and indicate a coupling between magnetic and optical properties, suggesting the possibility of carrier localization in the material. The presence of strong coupling between the exciton and the lattice may have important implications for the design of light-matter interactions in magnetic semiconductors and provides new insights into the exciton dynamics in CrSBr. This highlights the potential for exploiting exciton-phonon coupling to control the optical properties of layered antiferromagnetic materials.Comment: 21 pages, together with supp

Design of intelligent diagnosis system for ship power equipment

[Objectives] In order to adapt to the development of unmanned ships, strengthen the ship-shore integrated management of ship power equipment,reduce the workload of marine engineers, and realize on-condition maintenance of ship power equipment,this paper designs an intelligent diagnosis system of ship power equipment allowing for ship-shore integrated management.[Methods] According to the functions and features,the health status of components is evaluated with the single parameter threshold method and the radar chart,and the evaluation results are presented in the form of health scores. For components scored below 70 points, the system automatically enters the decision-making support interface,and the corresponding decision for a fault is provided for the engineer's reference. Taking the training ship "yukun" as the target ship,the intelligent diagnosis system of the actual ship power equipment is verified.[Results] The results of actual ship verification show that the intelligent diagnosis system of ship power equipment has high accuracy and operability,which realizes the transformation from "breakdown maintenance" to "on-condition maintenance".[Conclusions] The intelligent diagnosis system of ship power equipment helps improve the safety of ship operation and has certain practical value

Study on the Influence of Gradient Wind on the Aerodynamic Characteristics of a Two-Element Wingsail for Ship-Assisted Propulsion

It is well known that sail-assisted propulsion works under gradient wind conditions in the atmospheric boundary layer, and is an energy-saving device for fuel consumption. In order to study the aerodynamic characteristics of a wingsail in the atmospheric boundary layer above sea level, a transition SST turbulence model was used for numerical simulation of the wingsail with uniform and gradient wind conditions. We concluded that gradient wind conditions can delay the stall caused by an increased angle of attack. This is because the airflow on the suction surface of the wingsail in the spanwise direction exerts an acceleration towards the top of the wingsail. At the same time, supplementary airflow compresses the separated vortex, thus delaying the stall of the two-element wingsail. Under gradient wind conditions, the flow separation of the wingsail develops rapidly in the stall angles. Once a flat separation vortex is formed at the trailing edge of the wingsail, with the slow increase of flap deflection angle, flow separation rapidly expands and a deep stall occurs. Therefore, a small change of the flap deflection angle in the near-stall angles may lead to a deep stall of the wingsail, which should be avoided in engineering applications. Finally, the influence of the average speed of the gradient wind on the aerodynamic performance of the two-element wingsail was analyzed

Health Condition Assessment of Marine Systems Based on an Improved Radar Chart

Since health assessment plays a significant role in marine systems (MSs), it has caught the attention of researchers. In this study, a powerful evaluation method called an improved radar chart was developed as a means of reliability estimation. General evaluation methods applied in the comprehensive evaluation of MS are slightly insufficient in terms of considering index coordination. However, the application of a radar chart can solve this problem. To improving the shortcomings of a traditional radar chart, the fuzzy centralization statistical theory and the entropy weight were combined in this study to obtain the comprehensive weight. The weight could be converted into an angle, and it could reflect the influence degree of the indexes on the evaluation objects. Additionally, an angle bisector was introduced as an index axis, and the eigenvector was extracted to get the unique evaluation result. The result showed that the proposed method could achieve the continuous online monitoring of the system state, and the reliable and accurate assessment results were able to provide a reference for condition-based maintenance and decision-making

Can adopting lean startup strategy promote the sustainable development of new ventures? The mediating role of organizational iterative learning

When high uncertainty becomes the norm in entrepreneurship, entrepreneurial failure often becomes the first natural barrier that new ventures face. In dynamic environment, there is still a lack of clear answers on what strategic orientation new ventures need to adopt to improve organizational learning efficiency and achieve sustainable development. Lean startup theory believes that the entrepreneurial process is also a process where organizational cognition is constantly iterated and updated, which drives entrepreneurs to explore business opportunities through iteration learning and early customer insight. The paper aims to describe and examine the relationship between lean startup strategy, organizational iterative learning, and sustainable development of new ventures. This model is tested on the survey data of R&D departments of 325 technology new ventures in China. The research results show that: lean startup strategy can positively affect sustainable performance of new ventures; organizational iterative learning plays a mediating role in the relationship between lean startup strategy and sustainable development; market dynamics positively moderate the relationship between organizational iterative learning and sustainable development, while technology dynamics negatively moderate this relationship; furthermore, the two also moderate the process of lean startup strategy influencing sustainable development through organizational iterative learning, and that moderated mediating effect is significant. The research results reveal that entrepreneurs should deepen lean startup practices in new business layout, advocate the iteration and output of advanced knowledge, help enterprises establish proprietary knowledge barriers, and achieve sustainable development

Egg Freshness Evaluation Using Transmission and Reflection of NIR Spectroscopy Coupled Multivariate Analysis

This work presents a novel work for the detection of the freshness of eggs stored at room temperature and refrigerated conditions by the near-infrared (NIR) spectroscopy and multivariate models. The NIR spectroscopy of diffuse transmission and reflection modes was used to compare the quantitative and qualitative investigation of egg freshness. It was found that diffuse transmission is more conducive to the judgment of egg freshness. The linear discriminant analysis model (LDA) for pattern recognition based on the diffuse transmission measurement was employed to analyze egg freshness during storage. NIR diffuse transmission spectroscopy showed great potential for egg storage time discrimination in normal atmospheric conditions. The LDA model discrimination rated up to 91.4% in the prediction set, while only 25.6% of samples were correctly discriminated among eggs in refrigerated storage conditions. Furthermore, NIR spectra, combined with the synergy interval partial least squares (Si-PLS) model, showed excellent ability in egg physical index prediction under normal atmospheric conditions. The root means square error of prediction (RMSEP) values of Haugh unit, yolk index, and weight loss from predictive Si-PLS models were 4.25, 0.031, and 0.005432, respectively

Advances in Marine Self-Powered Vibration Sensor Based on Triboelectric Nanogenerator

With the rapid development of advanced electronics/materials and manufacturing, marine vibration sensors have made great progress in the field of ship and ocean engineering, which could cater to the development trend of marine Internet of Things (IoT) and smart shipping. However, the use of conventional power supply models requires periodic recharging or replacement of batteries due to limited battery life, which greatly causes too much inconvenience and maintenance consumption, and may also pose a potential risk to the marine environment. By using the coupling effect of contact electrification and electrostatic induction, triboelectric nanogenerators (TENGs) were demonstrated to efficiently convert mechanical vibration movements into electrical signals for sensing the vibration amplitude, direction, frequency, velocity, and acceleration. In this article, according to the two working modes of harmonic vibration and non-harmonic vibration, the latest representative achievements of TENG-based vibration sensors for sensing mechanical vibration signals are comprehensively reviewed. This review not only covers the fundamental working mechanism, rational structural design, and analysis of practical application scenarios, but also investigates the characteristics of harmonic vibration and non-harmonic vibration. Finally, perspectives and challenges regarding TENG-based marine self-powered vibration sensors at present are discussed

Genome-Wide Identification and Expression Analysis in Oxidative Stress of TCP Transcription Factor Family in Eggplant (Solanum melongena L.)

【Objective】The study was carried out to identify the SmTCP gene and analyze the members of SmTCP transcription factor family in eggplant. The determination of its expression under stress and hormone treatment laid a foundation for further study of the function of SmTCP gene in eggplant.【Method】The members of SmTCP gene family were identified from the eggplant genome. The physicochemical properties and distribution of members of SmTCP transcription factor family in eggplant were analyzed by bioinformatics methods. Eggplant seedlings were treated with high temperature (42 ℃), low temperature (4℃), salt stress (200 μmol/L NaCl solution), heavy metal (100 μmol/L CdCl2 solution), Pseudomonas solanacearum, salicylic acid and abscisic acid. The expression of SmTCP gene in eggplant under seven treatments was analyzed by qRT-PCR.【Result】A total of 32 SmTCP members were identified and analyzed by bioinformatics method. The results of qRT-PCR analysis showed that the SmTCP gene of eggplant was up-regulated in response to biological and environmental stress. Under hormone treatment, the SmTCP of eggplant was up-regulated generally after ABA treatment, and the SmTCP of eggplant was down-regulated generally after SA treatment. The contents of SmTCP in leaves and fruits were higher.【Conclusion】It was found that the SmTCP gene of eggplant express in response to stress. The expression of different SmTCP members in response to stress and the expression levels in various organs are different. Most of the Class I TCP members of eggplant are significantly up-regulated under heat stress. Therefore, it is speculated that the SmTCP gene of eggplant may be involved in resisting adversity stress

A Ring-Type Triboelectric Nanogenerator for Rotational Mechanical Energy Harvesting and Self-Powered Rotational Speed Sensing

In recent years, sensors have been moving towards the era of intelligence, miniaturization and low power consumption, but the power-supply problem has always been a key issue restricting the popularization and development of machine-mounted sensors on the rotating machinery. Herein, we develop a ring-type triboelectric nanogenerator (R-TENG) that functions as a sustainable power source as well as a self-powered rotational speed sensor for rotating machinery. The R-TENG adopts a freestanding mode and consists of a ring-type container unit, an end cover and polytetrafluoroethylene (PTFE) cylinders. In this study, the influence of the number of cylinders, the PTFE cylinder’s diameter and the rotational speed on the electrical output are systematically examined, and the motion law of the PTFE cylinders in the container is revealed by the experimental results and verified by kinetic simulation. At a rotational speed of 400 rpm, the output voltage, current and transferred charge of the designed R-TENG reached 138 V, 115 nC and 2.03 μA, respectively. This study provides an attractive power supply strategy for machine-mounted sensors of the rotating machinery, and the rotational speed measurement test also suggests the potential application of the R-TENG as a self-powered rotational speed sensor

Analysis of Marine Diesel Engine Emission Characteristics of Different Power Ranges in China

In order to accurately assess China’s port air pollution caused by the shipping industry, two main methods can be used to calculate the emissions of ships, including the method based on ship fuel consumption and the method based on ship activities. Both methods require accurate diesel engine emission factors, or specific emissions. In this paper, the emission characteristics of NOX, CO, CO2 and THC from 197 domestic marine diesel engines were tested under bench test conditions by a standard emission measurement system. The diesel engines were divided into six Classes, A~F, according to their power distribution, and the fuel-based emission factors and energy-based emission factors of marine main engine and auxiliary engine meeting IMO NOX Tier II standards were given. The results showed that the main engine fuel-based emission factors of NOX, CO, CO2 and THC from Class A to Class F were 33.25~76.58, 2.70~4.33, 3123.92~3166.47 and 1.10~2.64 kg/t-fuel, respectively; and the energy-based emission factors were 6.57~11.75, 0.56~0.81, 530.28~659.71 and 0.18~0.61 g/kW h, respectively. The auxiliary engine fuel-based emission factors of NOX, CO, CO2 and THC from Class A to Class D were 27.17~39.81, 2.66~5.12, 3113.01~3141.34 and 1.16~2.87 kg/t-fuel respectively; and their energy-based emission factors were 6.06~8.33, 0.47~0.77, 656.86~684.91 and 0.21~0.61 g/kW h, respectively. The emission factors for different types of diesel engines were closely related to the diesel engine load, and the relation between them could be expressed by quadratic polynomial or power function. The results of this paper provide valuable data for the estimation of waterway transportation exhaust emissions and comprehensive understanding of the emission characteristics of marine diesel engines