基于Moors谱峭度图的高速列车轴承故障诊断方法

由于高速列车轴承振动信号易受复杂工况下背景噪声及其他部件振源的影响,传统频谱分析方法很难准确地提取其故障特征。提出了一种基于Moors谱峭度图的列车轴承故障诊断方法,不仅很好地克服了背景噪声的干扰,而且解决了基于四阶矩谱峭度图算法中存在的鲁棒性问题,从而准确地提取出了列车轴承故障特征频率信息。试验平台上实测的高速列车轴承故障信号分析结果很好地验证了该方法的有效性及优越性,说明其具有良好的工程应用前景。

美国联邦最高法院判决Moors上诉案

生物技术产业界又获得一次胜利.约翰·摩尔企图为他那因发状细胞白血病治疗所需而被摘除的脾上的可用细胞争得一些钱财,这企图又一次被挫败. 美国最高法院驳回了一份对加利福尼亚最高法院的上诉.加州法院的原判不利于摩尔氏.间接牵涉到这一案情的一位律师麦克尔·特雷诺告诉本刊说,提交最高法院的上诉没有实质性内容,普遍预见不会成功.不过,摩尔还可以作别的指控,比如说指控医生未能覆行对受托人的责任等等.

Current observation and analysis based on mooring systems in the Andaman Sea

The basic structure and intraseasonal evolution of currents in the southeastern Andaman Sea was analyzed based on data collected in 2017 from two subsurface moorings(C1 and C5).Periodic variation in the upper ocean currents of the Andaman Sea was investigated by combining observational and satellite data.Mooring observations show that rapid changes of current speed and direction occurred in May and June,with a significant increase in current velocity at the C1 mooring.In the second half of the year,southward flow dominated at the C1 mooring,and alternating northward and southward flows were evident at the C5 mooring during the same period but the northward flow prevailed in boreal winter.In addition,analysis of the power spectra of the upper currents revealed that the tidal period at both moorings is primarily semidiurnal with weaker energy than that of the low-frequency currents.The upper ocean currents at the C1 and C5 moorings exhibited intraseasonal variation of 30-60 d and 120 d,while the zonal current at the C1 mooring exhibited a notable period of approximately 180 d.Further analysis indicated that the variability of currents in the Andaman Sea is influenced primarily by equatorial Kelvin waves and Rossby wave packets.Moreover,our results suggest that equatorial Kelvin waves from the eastern Indian Ocean entered the Andaman Sea in the form of Wyrtki Jets and propagated primarily along two distinct pathways during the observation period.In addition to coastal boundary Kelvin waves,it was found that a branch of the Wyrtki Jet that directly enters the Andaman Sea and flows northward along the slope of the continental shelf,and reflected Rossby wave packets by topography.

Intraseasonal variability of the Kuroshio observed via mooring at 18°N

Insufficient observations near the origin of the Kuroshio have led to incomplete understanding of the intraseasonal variability(ISV)of the Kuroshio.Direct measurements of the Kuroshio velocity were performed with an array of three profiler moorings(122.7°E,123°E,and 123.3°E)along 18°N from January 2018 to February 2020.The ISV of the Kuroshio at 18°N was investigated based on a combination of mooring observations and global high-resolution HYbrid Coordinate Ocean Model reanalysis data.The estimated time-averaged transport in the upper 350 m across the observation transect was 6.5±2.6 Sv(1.0 Sv=10^(6)m^(3)/s).Two significant ISV peaks at 50-60 and~100 d were recognized in the power spectra of the meridional velocity and transport.Further analysis indicated that the ISV at 50-60 d was caused by westward-propagating eddies at average propagation speed of~13 cm/s and wavelength of~635 km.Another ISV peak at~100 d was mainly caused by northward-propagating eddies generated in the North Equatorial Current region.Further investigation indicated that the ISV of the Kuroshio at 18°N is dominated by meridional transport,rather than by the zonal migration of the Kuroshio main axis.Our findings provide a better understanding of the ISV of the Kuroshio east of Luzon Island.

对称系泊半潜平台在各种可能系泊组合下的动力学分析

In this technologically advancing world,the demand for more energy,oil and gas production is rapidly escalating.To accomplish this,people have inclined more towards completely floating offshore structures,deployed in deep waters.A semi-submersible is selected in the present study,due to its better response characteristics and stability under harsh environmental conditions.The semi-submersible is position restrain with spread mooring lines incorporated with submerged buoy at different locations has been studied.A detailed numerical analysis is carried out using Ansys Aqwa for dynamic response analysis of semi-submersible under the combination of wind,wave,and current forces for 0°,45°,and 90°directions.It was observed that damping ratios and natural periods had been affected based on the position and number of submerged buoys in the mooring system.Also,reduction in mooring force after incorporating buoy in the mooring lines was observed.Subsequently,a Matlab code based on the S-N curve approach was generated and employed to investigate the fatigue damage of mooring lines under dynamic variation of mooring forces.When pegged with submerged buoys,fatigue life of mooring lines is increased under intact and postulated damaged mooring conditions.Moreover,coupling of motion responses of semi-submersible is observed,and unbounded response is not seen in any degrees-offreedom,even during damaged condition of mooring lines.

Variational Reconstruction and Simulation Experiments of Sea Surface Wind Field for Ocean Data Buoy

The sea surface wind field is an important physical parameter in oceanography and meteorology.With the continuous refinement of numerical weather prediction,air-sea interface materials,energy exchange,and other studies,three-dimensional(3D)wind field distribution at local locations on the sea surface must be measured accurately.The current in-situ observation of sea surface wind parameters is mainly achieved through the installation of wind sensors on ocean data buoys.However,the results obtained from this single-point measurement method cannot reflect wind field distribution in a vertical direction above the sea surface.Thus,the present paper proposes a theoretical framework for the optimal inversion of the 3D wind field structure variation in the area where the buoy is located.The variation analysis method is first used to reconstruct the wind field distribution at different heights of the buoy,after which theoretical analysis verification and numerical simulation experiments are conducted.The results indicate that the use of variational methods to reconstruct 3D wind fields is significantly effective in eliminating disturbance errors in observations,which also verifies the correctness of the theoretical analysis of this method.The findings of this article can provide a reference for the layout optimization design of wind measuring instruments in buoy observation systems and also provide theoretical guidance for the design of new observation buoys in the future.

考虑轴向大拉伸下弹性模量对聚酯系泊动态响应的影响

Owing to the particularity of a polyester fiber material,the polyester mooring undergoes large axial tensile deformation over long-term use.Large axial tensile deformation significantly impacts the dynamic response of the mooring system.In addition,the degrees of large axial tension caused by different elastic moduli are also different,and the force on the mooring line is also different.Therefore,it is of great significance to study the influence of elastic modulus on the dynamic results of the mooring systems under large axial tension.Conventional numerical software fails to consider the axial tension deformation of the mooring.Based on the theory of slender rods,this paper derives the formula for large axial tension using the method of overall coordinates and overall slope coordinates and provides the calculation programs.Considering a polyester mooring system as an example,the calculation program and numerical software are used to calculate and compare the static and dynamic analyses to verify the reliability of the calculation program.To make the force change of the mooring obvious,the elastic moduli of three different orders of magnitude are compared and analyzed,and the dynamic response results after large axial tension are compared.This study concludes that the change in the elastic modulus of the polyester mooring changes the result of the vertex tension by generating an axial tension.The smaller the elastic modulus,the larger the forced oscillation motion amplitude of the top point of the mooring line,the more obvious the axial tension phenomenon,and the smaller the force on the top of the polyester mooring.

青海产业结构与就业结构协调性分析研究

本文基于青海省1999—2023年相关经济数据,利用结构偏离度、协调系数和Moore值等统计计量方法,对青海省产业与就业结构协调度进行统计分析,并借助灰色关联度对就业结构的时滞期进行计算。研究发现,青海省产业结构已形成“三、二、一”结构,就业结构为“三、一、二”结构,在25年的发展过程中,就业结构逐步趋于合理,目前的主要问题在于第一产业就业人口无法实现有效转移,就业结构相对产业发展的时滞期为8年,需要政府采取有效政策,促进就业结构的进一步调整,仅供参考。

高等职业教育专业结构与产业结构互动关系中的时滞性问题研究——基于常州市的数据分析

高等职业教育专业结构与驻地区域产业、就业结构相互间的良性互动关系,可以有效提升区域社会经济发展动能,在三者的互动关系中,职业教育专业结构滞后于产业结构问题依然普遍存在。利用常州市2012—2020年的时间序列数据,采用Moore结构变化值统计方法,使用灰色关联度计算模型,对高等职业教育专业结构与产业、就业结构相互间的互动关系中的时滞性问题进行测算。研究结果显示,常州市高等职业教育专业发展滞后产业发展的时间为5年。

Fatty acid-binding protein gene is indispensable for molting process in Heortia vitessoides(Lepidoptera:Crambidae)

As intracellular fatty acid(FA) carriers,FA-binding proteins(FABPs) widely participate in the absorption,transport,and metabolism of FAs.It is a key protein in insect lipid metabolism and plays an important role in various physiological activities of insects.An FABP gene(HvFABP) was cloned from the transcriptional library of Heortia vitessoides Moore(Lepidoptera:Crambidae),and its expression patterns were determined using reverse transcription quantitative PCR(RTqPCR).Stage-and tissue-specific expression profiles indicated that HvFABP highly expressed from prepupal to adult stages and in larval midgut and adult wings.HvFABP expression may be induced through starvation,mRNA expression was downregulated at 24 and 48 h and upregulated at 72 h after starvation.Furthermore,20-hydroxyecdysone can induce the upregulation of its expression.RNA interference-mediated silencing of Hv FABP significantly inhibited HvFABP expression,resulting in delayed development,abnormal molting or lethal phenotypes,and a significantly reduced survival rate.These results indicate that HvFABP plays a key role in the molting of H.vitessoides.

Understanding the adoption context of China’s digital currency electronic payment

Central banks worldwide have started researching and developing central bank digital currencies(CBDCs).In the digital economy context,concerns regarding the integrity,competition,and privacy of CBDC systems have also gradually emerged.Against this backdrop,this study aims to evaluate users’willingness to use China’s digital currency electronic payment(DCEP)system,a digital payment and processing network,and its influencing factors by comprehensively considering and comparing the characteristics of cash and third-party payment services.Combining the push-pull-mooring frame-work(PPM)and task-technology fit(TTF)theory,we discuss the scenarios and mecha-nisms that may inspire users’DCEP adoption intention through an empirical study.The results reveal that privacy concerns regarding the original payment methods and technology-task fitting level of DCEP positively impact users’willingness to adopt DCEP.The technical characteristics of DCEP,users’payment requirements,and government support positively affect users’adoption intention by influencing the task-technology fitting degree of DCEP.Switching cost significantly and negatively impacts adop-tion intention,whereas relative advantage exhibits no significant effect.This research contributes to a better understanding of the factors that influence switching intentions and the actual use of DCEP,and provides policy guidance on promoting the efficiency and effectiveness of DCEP.

Study on the Characteristics of A New Hybrid Mooring System for DualPlatform Joint Operations

As the sustainable exploitation of marine resources develops,dual-platform joint operation has caught increasing attention.Dual-platform joint operation requires smaller relative motion between the two sub-platforms,which is normally difficult to be satisfied by the traditional mooring system.Therefore,a new hybrid mooring system is developed and studied in this article.To ensure safety during platform movements,both the number of anchor chains and the relative motion between the two sub-platforms are reduced in the new hybrid mooring system.By performing numerical simulations based on three-dimensional potential flow theory in AQWA and physical experiments,the performances of both the new hybrid and traditional mooring systems under two different wave conditions(i.e.,working wave and freak wave conditions) are systematically investigated.Regarding the new hybrid mooring system,the relative stability between the two sub-platforms of the new system is better,and the platforms can restore stability faster when affected by freak waves.

Comparative coherence between layered and traditional semiconductors: unique opportunities for heterogeneous integration

As Moore’s law deteriorates,the research and development of new materials system are crucial for transitioning into the post Moore era.Traditional semiconductor materials,such as silicon,have served as the cornerstone of modern technologies for over half a century.This has been due to extensive research and engineering on new techniques to continuously enrich silicon-based materials system and,subsequently,to develop better performed silicon-based devices.Meanwhile,in the emerging post Moore era,layered semiconductor materials,such as transition metal dichalcogenides(TMDs),have garnered considerable research interest due to their unique electronic and optoelectronic properties,which hold great promise for powering the new era of next generation electronics.As a result,techniques for engineering the properties of layered semiconductors have expanded the possibilities of layered semiconductor-based devices.However,there remain significant limitations in the synthesis and engineering of layered semiconductors,impeding the utilization of layered semiconductor-based devices for mass applications.As a practical alternative,heterogeneous integration between layered and traditional semiconductors provides valuable opportunities to combine the distinctive properties of layered semiconductors with well-developed traditional semiconductors materials system.Here,we provide an overview of the comparative coherence between layered and traditional semiconductors,starting with TMDs as the representation of layered semiconductors.We highlight the meaningful opportunities presented by the heterogeneous integration of layered semiconductors with traditional semiconductors,representing an optimal strategy poised to propel the emerging semiconductor research community and chip industry towards unprecedented advancements in the coming decades.

An Improved Approach for Interaction of Wave with Floating Spheres and Its Applications

To develop and utilize marine resources in the deep sea, the higher requirements for floating structures, which are operated in marine environment for a long term, have been put forward. Reasonable structure type and accurate force analysis are favorable guarantees to improve the survival performance and working performance of the floating structures. Floating spheres fastened by mooring cable were widely used in floating structures. In this paper, the wave forces of the floating sphere are efficiently and accurately calculated by solving the geometric relationship between the non-submerged floating sphere and wave surface. Combined with the hydrodynamic calculation of mooring cables based on the lumped mass method, the coupled motion model of multi-floating spheres fastened by multi-mooring cable was established under wave action. Furthermore, according to the floating structures fastened by mooring cable in the actual ocean engineering, the topological method of multi-mooring cables fastening the multifloating spheres was expounded from simple to complex. Finally, the modeling method and preliminarily hydrodynamic characteristics of the fastened floating structures, including the mooring system of renewable energy devices, ocean buoy, and coral nursery, were presented and analyzed in detail. The obtained results showed that the method for calculating the wave force on the floating sphere developed in this paper can accurately describe the motion process of the floating mooring sphere and the force on the mooring cable. Also, the topological method of multiple buoys and multiple mooring cables could efficiently establish various numerical hydrodynamic models of fastened buoys in ocean engineering.

Motion simulation of moorings using optimized LSTM neural network

Mooring arrays have been widely deployed in sustained ocean observation in high resolution to measure finer dynamic features of marine phenomena.However,the irregular posture changes and nonlinear response of moorings under the effect of ocean currents face huge challenges for the deployment of mooring arrays,which may cause the deviations of measurements and yield a vacuum of observation in the upper ocean.We developed a data-driven mooring simulation model based on LSTM(long short-term memory)neural network,coupling the ocean current with position data from moorings to predict the motion of moorings,including single-step output prediction and multi-step prediction.Based on the predictive information,the formation of the mooring array can be adjusted to improve the accuracy and integrity of measurements.Moreover,we proposed the cuckoo search(CS)optimization algorithm to tune the parameters of LSTM,which improves the robustness and generalization of the model.We utilize the datasets observed from moorings anchored in the Kuroshio Extension region to train and validate the simulation model.The experimental results demonstrate that the model can remarkably improve prediction accuracy and yield stable performance.Moreover,compared with other optimization algorithms,CS is more efficient and performs better in simulating the motion of moorings.

锚泊线海床开槽与锚泊基础承载力研究进展综述

Mooring systems are usually adopted to position floating structures,including mooring lines and anchors,and directly determine the safety of floating structures.Seabed inspection reported that seabed trenches induced by mooring line-soil interaction appear in front of the anchor and reduce the anchor bearing capacity.This work first introduces the research progress of mooring line-soil interaction and seabed trenching simulation.Research about the suction anchor capacity in clay and sand is presented,and the seabed trench influence on anchor capacity is analyzed.For anchor analysis,this study gives a new perspective to analyze anchor installation and bearing capacity,i.e.,structure-soil interface characteristic.Some common anchor types are analyzed.Results showed that seabed trench simulation is still needed to acquire trench 3D profiles,in which the mooring line-soil dynamic interaction cannot be ignored.At present,the trench influence is not considered in suction anchor design,making the design dangerous.For the anchor,the interface shear characteristics control the most unfavorable loading conditions.Thus,accurate interface parameters should be obtained for anchor analysis.

Orthogonal Frequency Division Multiplexing Adaptive Technology for Multinode Users of Seawater Channel Based on Inductively Coupled Mooring Chain

As an important part of buoy-type ocean monitoring systems,the inductively coupled mooring chain solves the problem of data cotransmission through the multinode sensors that it carries,which is significant for the rapid acquisition of fish,hydrology,and other information.This paper is based on a seawater channel transmission model with a depth of 300 m and a bandwidth of 2 MHz.An orthogonal frequency division multiplexing(OFDM)technology is used to overcome the multipath effect of signal transmission on a seawater medium.The adaptive technology is integrated into the OFDM,and an improved joint subcarrier and bit power allocation algorithm is proposed.This algorithm solves the problem of dynamic subcarrier allocation during the cotransmission of underwater multinode user data in seawater channels.The results show that the algorithm complexity can be reduced by 0.18126×10^(-2)s during one complete OFDM system data transmission by the improved greedy algorithm,and a total of 216 bits are transmitted by the OFDM.The normalized channel capacity can be improved by 0.012 bit s^(-1)Hz^(-1).At the bit error ratio(BER)of 10^(-3),the BER performance can be improved by approximately 6 d B.When the numbers of users are 4 and 8,the improved algorithm increases the channel capacity,and the higher the number of users,the more evident the channel capacity improvement effect is.The results of this paper have an important reference value for enhancing the transmission performance of inductively coupled mooring chain underwater multinode data.

Comparison Study and Forensic Analysis between Experiment and Coupled Dynamics Simulation for Submerged Floating Tunnel Segment with Free Ends under Wave Excitations

This paper presents dynamic-behavior comparisons and related forensic analyses of a submerged floating tunnel(SFT)between numerical simulation and physical experiment under regular and irregular waves.The experiments are conducted in the 3Dwave tank with 1:33.3 scale,and the corresponding coupled time-domain simulation tool is devised for comparison.The entire SFT systemconsists of a long concrete tunnel and 12 tubular aluminummooring lines.Two numerical simulation models,the Cummins equation with 3D potential theory including second-order wave-body interaction effects and the much simpler Morison-equation-based formula with the lumped-massbased line model,are designed and compared.Forensic analyses for mooring-line adjustments in the simulation are carried out in view of the best representation of the physical system.After that,the measured pre-tension distribution and systemstiffness of twelvemooring lines arewell reproduced in the numericalmodel.Subsequently,the dynamic responses and mooring tensions of the SFT are compared under regular and irregular waves.The measured and simulated results coincide reasonably well for both regular-and irregular-wave conditions.

半潜船波浪诱导运动与载荷预报数值方法比较研究

Numerical simulation tools based on potential-flow theory and/or Morison’s equation are widely used for predicting the hydrodynamic responses of floating offshore wind platforms.In general,these simplified approaches are used for the analysis under operational conditions,albeit with a carefully selected approach to account for viscous effects.Nevertheless,due to the limit hydrodynamic modelling to linear and weakly nonlinear models,these approaches severely underpredict the low-frequency nonlinear wave loads and dynamic responses of a semisubmersible.They may not capture important nonlinearities in severe sea states.For the prediction of wave-induced motions and loads on a semisubmersible,this work systematically compares a fully nonlinear viscous-flow solver and a hybrid model combining the potential-flow theory with Morison-drag loads in steep waves.Results show that when nonlinear phenomena are not dominant,the results obtained by the hybrid model and the high-fidelity method show reasonable agreement,while larger discrepancies occur for highly nonlinear regular waves.Specifically,regular waves with various steepness over different frequencies are focused in the present study,which supplements the understanding in applicability of these two groups of method.

Mathematical Modeling of Moored Ship Motion in Arbitrary Harbor utilizing the Porous Breakwater

The motion of the moored ship in the harbor is a classical hydrodynamics problem that still faces many challenges in naval operations,such as cargo transfer and ship pairings between a big transport ship and some small ships.A mathematical model is presented based on the Laplace equation utilizing the porous breakwater to investigate the moored ship motion in a partially absorbing/reflecting harbor.The motion of the moored ship is described with the hydrodynamic forces along the rotational motion(roll,pitch,and yaw)and translational motion(surge,sway,and heave).The efficiency of the numerical method is verified by comparing it with the analytical study of Yu and Chwang(1994)for the porous breakwater,and the moored ship motion is compared with the theoretical and experimental data obtained by Yoo(1998)and Takagi et al.(1993).Further,the current numerical scheme is implemented on the realistic Visakhapatnam Fishing port,India,in order to analyze the hydrodynamic forces on moored ship motion under resonance conditions.The model incorporates some essential strategies such as adding a porous breakwater and utilizing the wave absorber to reduce the port’s resonance.It has been observed that these tactics have a significant impact on the resonance inside the port for safe maritime navigation.Therefore,the current numerical model provides an efficient tool to reduce the resonance within the arbitrarily shaped ports for secure anchoring.