Effects of drive imbalance on the particle emission from a Bose-Einstein condensate in a one-dimensional lattice

Time-periodic driving has been an effective tool in the field of nonequilibrium quantum dynamics,which enables precise control of the particle interactions.We investigate the collective emission of particles from a Bose-Einstein condensate in a one-dimensional lattice with periodic drives that are separate in modulation amplitudes and relative phases.In addition to the enhancement of particle emission,we find that amplitude imbalances lead to energy shift and band broadening,while typical relative phases may give rise to similar gaps.These results offer insights into the specific manipulations of nonequilibrium quantum systems with tone-varying drives.

Research on Driver’s Fatigue Detection Based on Information Fusion

Driving fatigue is a physiological phenomenon that often occurs during driving.After the driver enters a fatigued state,the attentionis lax,the response is slow,and the ability todeal with emergencies is significantly reduced,which can easily cause traffic accidents.Therefore,studying driver fatigue detectionmethods is significant in ensuring safe driving.However,the fatigue state of actual drivers is easily interfered with by the external environment(glasses and light),which leads to many problems,such as weak reliability of fatigue driving detection.Moreover,fatigue is a slow process,first manifested in physiological signals and then reflected in human face images.To improve the accuracy and stability of fatigue detection,this paper proposed a driver fatigue detection method based on image information and physiological information,designed a fatigue driving detection device,built a simulation driving experiment platform,and collected facial as well as physiological information of drivers during driving.Finally,the effectiveness of the fatigue detection method was evaluated.Eye movement feature parameters and physiological signal features of drivers’fatigue levels were extracted.The driver fatigue detection model was trained to classify fatigue and non-fatigue states based on the extracted features.Accuracy rates of the image,electroencephalogram(EEG),and blood oxygen signals were 86%,82%,and 71%,separately.Information fusion theory was presented to facilitate the fatigue detection effect;the fatigue features were fused using multiple kernel learning and typical correlation analysis methods to increase the detection accuracy to 94%.It can be seen that the fatigue driving detectionmethod based onmulti-source feature fusion effectively detected driver fatigue state,and the accuracy rate was higher than that of a single information source.In summary,fatigue drivingmonitoring has broad development prospects and can be used in traffic accident prevention and wearable driver fatigue recognition.

Controlled thermally-driven mass transport in carbon nanotubes using carbon hoops

Controlling mass transportation using intrinsic mechanisms is a challenging topic in nanotechnology.Herein,we employ molecular dynamics simulations to investigate the mass transport inside carbon nanotubes(CNT)with temperature gradients,specifically the effects of adding a static carbon hoop to the outside of a CNT on the transport of a nanomotor inside the CNT.We reveal that the underlying mechanism is the uneven potential energy created by the hoops,i.e.,the hoop outside the CNT forms potential energy barriers or wells that affect mass transport inside the CNT.This fundamental control of directional mass transportation may lead to promising routes for nanoscale actuation and energy conversion.

A Multiscale Reliability-Based Design Optimization Method for Carbon-Fiber-Reinforced Composite Drive Shafts

Carbon fiber composites,characterized by their high specific strength and low weight,are becoming increasingly crucial in automotive lightweighting.However,current research primarily emphasizes layer count and orientation,often neglecting the potential of microstructural design,constraints in the layup process,and performance reliability.This study,therefore,introduces a multiscale reliability-based design optimization method for carbon fiber-reinforced plastic(CFRP)drive shafts.Initially,parametric modeling of the microscale cell was performed,and its elastic performance parameters were predicted using two homogenization methods,examining the impact of fluctuations in microscale cell parameters on composite material performance.A finite element model of the CFRP drive shaft was then constructed,achieving parameter transfer between microscale and macroscale through Python programming.This enabled an investigation into the influence of both micro and macro design parameters on the CFRP drive shaft’s performance.The Multi-Objective Particle Swarm Optimization(MOPSO)algorithm was enhanced for particle generation and updating strategies,facilitating the resolution of multi-objective reliability optimization problems,including composite material layup process constraints.Case studies demonstrated that this approach leads to over 30%weight reduction in CFRP drive shafts compared to metallic counterparts while satisfying reliability requirements and offering insights for the lightweight design of other vehicle components.

Uphill or downhill?Cropland use change and its drivers from the perspective of slope spectrum

The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic factors.However,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains rare.To address the gap,in virtue of spatial analysis and geographically weighted regression(GWR)model,the cropland use change in the Yangtze River Basin(YRB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope spectrum.Results showed that the slope spectrum curves of cropland area-frequency in the YRB showed a first upward then a downward trend.The change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution patterns.Quantitative analysis of morphological parameters of cropland slope spectrum revealed that the further down the YRB,the stronger the flattening characteristics,the more obvious the concentration.The province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was Zhejiang.The most common cropland use change type in the YRB was horizontal expansion type.The factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study period.This research is of practical significance for the rational utilization of cropland at the watershed scale.

Heberlein jet technology drives innovations in demanding technical applications

Heberlein Technology AG,Wattwil,Switzerland,March 7,2024–Unique technology for creating advanced technical textiles with exquisite characteristics was featured at the Techtextil in Germany.Heberlein,the leading supplier of air interlacing and air texturing jets,plans to convince visitors to the event with critical components–such as the latest PolyJet-TG-3–that can influence both yarn properties and processes.

Nullmax纽劢 MaxDrive行泊一体方案

是目前市面上极少有的真融合行泊一体4.0形态方案,具有高准度、高稳定、强性能、易落地的产品优势,传感器深度复用、芯片资源共享、安全高效经济,可满足客户各类需求。立足于Nullmax平台化BEV-AI技术架构,兼顾技术性能和部署成本的双重需求,支持高中低不同算力平台,适配任意传感器,可根据需求进行定制化开发,快速完成全场景智能驾驶功能的量产应用,且向上拓展性极强。

毫末智行 自动驾驶大模型 DriveGPT雪湖·海若

行业首个自动驾驶生成式大模型DriveGPT(雪湖·海若)为大模型技术落地自动驾驶提供了新范式。DriveGPT是由毫末自研的自动驾驶认知大模型升级而来,最初目的主要是解决自动驾驶的认知决策优化问题,其基本过程是在认知模块引入真实人驾数据,通过人类反馈强化学习技术,对自动驾驶认知决策模型进行持续优化。当前毫末正在通过引入感知大模型,将DriveGPT升级为通用大模型架构,目标是实现端到端自动驾驶。

Microstructure,mechanical property and in vitro biocorrosion behavior of single-phase biodegradable Mg-1.5Zn-0.6Zr alloy

The microstructure,mechanical property,and in vitro biocorrosion behavior of as-cast single-phase biodegradable Mg-1.5Zn-0.6Zr alloy were investigated and compared with a commercial as-cast AZ91D alloy.The results show that the Mg-1.5Zn-0.6Zr alloy had a single-phase solid solution structure,with an average grain size of 34.7±13.1μm.The alloy exhibited ultimate tensile strength of 168±2.0 MPa,yield strength of 83±0.6 MPa,and elongation of 9.1±0.6%.Immersion tests and electrochemical measurements reveal that the alloy displayed lower biocorrosion rate and more uniform corrosion mode than AZ91D in Hank's solution.The elimination of intensive galvanic corrosion reactions and the formation of a much more compact and uniform corrosion film mainly account for the better biocorrosion properties of the Mg-1.5Zn-0.6Zr alloy than AZ91D.

Dynamic behavior of coalbed methane flow along the annulus of single-phase production

Dynamic behavior of coalbed methane (CBM) flow will provide the theoretical basis to optimize production performance for a given well.A mathematical model is developed to simulate flowing pressures and pressure drops of CBM column from well head to bottom hole.The measured parameters and independent variables of flow rates,flowing pressures and temperatures are involved in CBM producing process along the annulus.The developed relationships are validated against full-scale measured data in single-phase CBM wellbores.The proposed methodology can analyze the dynamic behavior in CBM reservoir and process of CBM flow with an overall accuracy of 2%.The calculating process of flowing pressures involves friction factor with variable Reynolds number and CBM temperature and compressibility factor with gravitational gradients.The results showed that the effect of flowing pressure on CBM column was more obvious than that on CBM and water column accompanied by an increase of dynamic water level.The ratios of flowing pressure on increment of CBM column to the whole column increased with the declined flow rates of water column.Bottom-hole pressure declined with the decreased flowing pressure of CBM column along the annulus.It will lead to the results of the increased pressure drop of CBM column and CBM flow rate in single-phase CBM wellbores.

Prediction of Outdoor Noise Propagation Induced By Single-Phase Power Transformers

Outdoor power transformers are one of the most pervasive noise sources in power transmission and distribution systems.Accurate prediction of outdoor noise propagation plays a dominant role for the evaluation and control of noise relevant to the transformer stations.In this paper surface vibration tests are carried out on a scale model of a single-phase transformer tank wall at different excitation frequencies.The phase and amplitude of test data are found to be randomly distributed when the excitation frequency exceeds the seventh mode frequency,which allows the single-phase power transformer to be simplified as incoherent point sources.An outdoor-coherent model is subsequently developed and incorporated with the image source method to investigate noise propagation from single-phase power transformers,due to the occurrence of multiple reflections and diffractions in the propagation path of each point source.The proposed model is used to calculate the sound field of the power transformer group by exploiting the additional phase information.In comparison with the ISO9613 model and the boundary element method,it is found that the proposed coherent image source method leads to more accurate prediction results,and hence better performance for the prediction of the outdoor noise induced by single-phase power transformers.

Symmetrical dynamical characteristic of peak and valley current-mode controlled single-phase H-bridge inverter

Complex dynamical phenomenon was studied in the single phase H-bridge inverter which was controlled by either a peak current or a valley current. The state functions and the discrete iterative map equations were established to analyze the dynamical phenomenon in the single phase H-bridge inverter. The dynamical characteristics of the single phase H- bridge inverter, such as time domain waveform diagram, bifurcation diagram, and folding map, were obtained by using the numerical calculation when the circuit parameters varied in specific range. Moreover, the simulation results were obtained by using the OrCAD-PSpice software to validate the numerical calculation. Both the numerical calculation and the circuit simulation show that the symmetrical dynamical phenomenon occurs in the single phase H-bridge inverter controlled by the peak current or the valley current.

The Use of Single-Phase Immersion Cooling by Using Two Types of Dielectric Fluid for Data Center Energy Savings

Data centers are recognized as one of the most important aspects of the fourth industrial revolution since conventional data centers are inefficient and have dependency on high energy consumption,in which the cooling is responsible for 40%of the usage.Therefore,this research proposes the immersion cooling method to solving the high energy consumption of data centers by cooling its component using two types of dielectric fluids.Four stages of experimentalmethods are used,such as fluid types,cooling effectiveness,optimization,and durability.Furthermore,benchmark software is used to measure the CPU maximum work with the temperature data performed for 24 h.The results of this study show that the immersion cooling reduces 13℃ lower temperature than the conventional cooling method which means it saves more energy consumption in the data center.The most optimum variable used to decrease the temperature is 1.5 lpm of flow rate and 800 rpm of fan rotation.Furthermore,the cooling performance of the dielectric fluids shows that the mineral oil(MO)is better than the virgin coconut oil(VCO).In durability experiment,there are no components damage after five months immersed in the fluid.

Real-Time Method for Detecting Harmonic and Reactive Currents of Single-Phase Circuits

According to the characteristics of single-phase circuits and demand of using active filter for real-time detecting harmonic and reactive currents, a detecting method based on Fryze＇s power definition is proposed. The results of theoretical analysis and simula- tion show that the proposed method is effective in realtime detecting of instantaneous harmonic and reactive currents in single-phase circuits. When only detecting the total reactive currents, this method does not need a phase-locked loop circuit, and it also can be used in some special applications to provide different compensations on the ground of different requirements of electric network. Compared with the other methods based on the theory of instantaneous reactive power, this method is simple and easy to realize.

Modified surface tension model for free surface flow with single-phase lattice Boltzmann method

A single-phase lattice Boltzmann model with modified surface tension is developed in this paper to solve the problem of high-density-ratio free surface flow.The computational efficiency and accuracy are both enhanced.The restriction to the relaxation factor （which needs to be smaller than 1） is circumvented by the new surface tension algebra,due to its rational physical nature compared with the treatment of Xing,Buther and Yang in their paper （Comp.Mater.Sci.,2007,39（2）：282-290）.The proposed stable surface tension scheme is applied to simulate the free deformation of a square droplet with surface tension effect and the process of a droplet impinging on a liquid film.The numerical solution for free deformation of a droplet agrees well with thermodynamic principles,and also achieves high accuracy in comparison with Xing,et al.＇s model.Three typical impinging modes are successfully obtained with the new scheme,and another particular mode found by Wang and Chen is also successfully simulated.The evolutions of liquid crown agree well with the power law related to time.

Industrial frequency single-phase AC traction power supply system for urban rail transit and its key technologies

To avoid stray current and maintain the benefit of no phase-split in the DC traction power supply system, an AC traction power supply system was proposed for the urban public transport such as metro and light rail transit. The proposed system consists of a main substation （MSS） and cable traction network （CTN）. The MSS includes a single-phase main traction transformer and a negative-se- quence compensation device, while the CTN includes double-core cables, traction transformers, overhead catenary system, rails, etc. Several key techniques for the proposed system were put forward and discussed, which can be summarized as （1） the power supply principle, equivalent circuit and transmission ability of the CTN, the cable-catenary matching technique, and the selection of catenary voltage level; （2） the segmentation technology and status identification method for traction power supply network, distributed and centralized protection schemes, etc.; （3） a power supply scheme for single-line MSS and a power supply scheme of MSS shared by two or more lines. The proposed industrial frequency single-phase AC traction power supply system shows an excellent technical performance, good economy, and high reliability, hence provides a new alternative for metro and urban rail transit power supply systems.

A Single-phase of Supercritical CO_2/Polystyrene Solution in Foam Extrusion

The high quality single-phase solution of CO2/ Polystyrene was achieved,by analyzing the influential factors for polymer microcellular foaming extrusion.The curve of pressure distribution along the barrel was determined.The axial position of gas-injecting port on the barrel was chosen form the results of stable foaming,and the number of gas-injecting ports in the circumference of the barrel was determined from the CO2 solubility in polymer.The effect of the screw rotation speed on CO2 solubility was studied,and the effects of pressure difference between the gas and the polymer melt on gas-injecting process and on the foaming stability were investigated.The influence of the gas temperature before injection on the single-phase of CO2/Polystyrene solution also was studied.

A quasi single-phase model for debris flows and its comparison with a two-phase model

A depth-averaged quasi single-phase mixture model is proposed for debris flows over inclined bed slopes based on the shallow water hydrosediment-morphodynamic theory with multi grain sizes. The stresses due to fluctuations are incorporated based on analogy to turbulent flows, as estimated using the depth-averaged k-? turbulence model and a modification component. A fully conservative numerical algorithm, using wellbalanced slope limited centred scheme, is deployed to solve the governing equations. The present quasi single-phase model using four closure relationships for the bed shear stresses is evaluated against USGS experimental debris flow and compared with traditional quasi single-phase models and a recent physically enhanced two-phase model. It is found that the present quasi single-phase model performs much better than the traditional models, and is attractive in terms of computational cost while the two-phase model performs even better appreciably.

Mixture Regression-Cum-Ratio Estimator Using Multi-Auxiliary Variables and Attributes in Single-Phase Sampling

In this paper, we have proposed a class of mixture regression-cum-ratio estimator for estimating population mean by using information on multiple auxiliary variables and attributes simultaneously in single-phase sampling and analyzed the properties of the estimator. An empirical was carried out to compare the performance of the proposed estimator with the existing estimators of finite population mean using simulated population. It was found that the mixture regression-cum-ratio estimator was more efficient than ratio and regression estimators using one auxiliary variable and attribute, ratio and regression estimators using multiple auxiliary variables and attributes and regression-cum-ratio estimators using multiple auxiliary variables and attributes in single-phase sampling for finite population.