Experimental and Numerical Investigation on the Aerodynamic Characteristics of High-Speed Pantographs with Supporting Beam Wind Deflectors

Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)simulations.The results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force compensation.They also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”shape.Moreover,the lift force compensation provided by the wind deflectors increases with the size of the deflector.Alternative wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.

Exploration of the efficacy and mechanism of treating head wind disease with the combination change of ginger volatile oil and gingerol by using content-weighted network pharmacology technology

Background:Exploring the efficacy,potential components,and mechanism of the combination of ginger essential oil and gingerols in the treatment of head wind disease based on network pharmacology technology with content weight.Methods:The experimental groups were divided into:0:10,1:4,1:2,1:1,2:1,4:1,10:0.The relative content(Ri)of the chemical constituents of ginger's volatile oil was determined using gas chromatography-mass spectrometry(GC-MS).Additionally,the physicochemical and biological property parameters(LogP,MDCK,PPB,MW)of the components were considered.To assess the quantitative effect of the components,a grading score was performed,and the quantitative effect index(Ki)was calculated.Subsequently,the target effect index(Ti)was calculated by combining the component-target matching score(Fit score).Using these calculations,the target effect score A was determined under the influence of multiple components targeting different targets.Key targets with A≥1000 were identified.To predict the targets related to head wind disease,the Comparative Toxicogenomics Database(https://ctdbase.org/),Gene Cards(https://www.genecards.org/),and Disgenet database(https://www.disgenet.org/)were utilized.The key targets,obtained from different proportions of ginger's volatile oil and gingerol,were intersected with the predicted targets.This facilitated network pharmacological analysis and verification of the efficacy.Results:The content of volatile oil in ginger demonstrated an impact on key targets associated with the volatile oil group.Each specific combination of volatile oil consistently activated distinct pathways,with variations stemming from changes in content.Experimental testing revealed that different combinations of ginger's volatile oil and gingerol effectively alleviated migraine symptoms in rats.Conclusion:Through the application of content-weighted network pharmacology technology and pharmacodynamic verification,it was determined that altering the ratio between ginger's volatile oil and gingerol leads to variations in potential targets and pathways,consequently impacting its efficacy.

Study on the operational safety of high-speed trains exposed to stochastic winds

The characteristic wind curve （CWC） was com- monly used in the previous work to evaluate the operational safety of the high-speed trains exposed to crosswinds. How- ever, the CWC only provide the dividing line between safety state and failure state of high-speed trains, which can not evaluate the risk of derailment of high-speed trains when ex- posed to natural winds. In the present paper, a more realistic approach taking into account the stochastic characteristics of natural winds is proposed, which can give a reasonable and effective assessment of the operational safety of high-speed trains under stochastic winds. In this approach, the longitudi- nal and lateral components of stochastic winds are simulated based on the Cooper theory and harmonic superposition. An algorithm is set up for calculating the unsteady aerody- namic forces （moments） of the high-speed trains exposed to stochastic winds. A multi-body dynamic model of the rail vehicle is established to compute the vehicle system dynamic response subjected to the unsteady aerodynamic forces （mo- ments） input. Then the statistical method is used to get the mean characteristic wind curve （MCWC） and spread range of the high-speed trains exposed to stochastic winds. It is found that the CWC provided by the previous analyticalmethod produces over-conservative limits. The methodol- ogy proposed in the present paper can provide more signif- icant reference for the safety operation of high-speed trains exposed to stochastic winds.

Effect of ambient wind on pressure wave generated by high-speed train entering a tunnel

Using three-dimensional, unsteady N-S equations and k-ε turbulence model, the effect of ambient wind on the pressure wave generated by a high-speed train entering a tunnel was studied via numerical simulation. Pressure changes of the train surface and tunnel wall were obtained as well as the flow field around the train. Results show that when the train runs downwind, the pressure change is smaller than that generated when there is no wind. When the train runs upwind, the pressure change is larger. The pressure change is more sensitive in the upwind condition than in the downwind condition. Compared with no wind condition, when the wind velocity is 10 m/s and 30 m/s, the pressure amplitude on the train head is reduced by 2.8% and 10.5%, respectively. The wall pressure amplitude at 400 m away from the tunnel entrance is reduced by 2.4% and 13.5%, respectively. When the wind velocity is-10 m/s and-30 m/s, the pressure amplitude on the train head increases by 3.0% and 17.7%, respectively. The wall pressure amplitude at 400 m away from the tunnel entrance increases by 3.6% and 18.6%, respectively. The pressure waveform slightly changes under ambient wind due to the influence of ambient wind on the pressure wave propagation speed.

An Investigation into the Effects of the Reynolds Number on High-Speed Trains Using a Low Temperature Wind Tunnel Test Facility

A series of tests have been conducted using a Cryogenic Wind Tunnel to study the effect of Reynolds number(Re)on the aerodynamic force and surface pressure experienced by a high speed train.The test Reynolds number has been varied from 1 million to 10 million,which is the highest Reynolds number a wind tunnel has ever achieved for a train test.According to our results,the drag coefficient of the leading car decreases with higher Reynolds number for yaw angles up to 30º.The drag force coefficient drops about 0.06 when Re is raised from 1 million to 10 million.The side force is caused by the high pressure at the windward side and the low pressure generated by the vortex at the lee side.Both pressure distributions are not appreciably affected by Reynolds number changes at yaw angles up to 30°.The lift force coefficient increases with higher Re,though the change is small.At a yaw angle of zero the down force coefficient is reduced by a scale factor of about 0.03 when the Reynolds number is raised over the considered range.At higher yaw angles the lift force coefficient is reduced about 0.1.Similar to the side force coefficient,the rolling moment coefficient does not change much with Re.The magnitude of the pitching moment coefficient increases with higher Re.This indicates that the load on the front bogie is higher at higher Reynolds numbers.The yawing moment coefficient increases with Re.This effect is more evident at higher yaw angles.The yawing moment coefficient increases by about 6%when Re is raised from 1 million to 10 million.The influence of Re on the rolling moment coefficient around the leeward rail is relatively smaller.It increases by about 2%over the considered range of Re.

Operational Safety Assessment of a High-Speed Train Exposed to the Strong Gust Wind

The operational safety characteristics of trains exposed to a strong wind have caused great concern in recent years.In the present paper,the effect of the strong gust wind on a high-speed train is investigated.A typical gust wind model for any wind angle,named“Chinese hat gust wind model”,was first constructed,and an algorithm for computing the aerodynamic loads was elaborated accordingly.A vehicle system dynamic model was then set up in order to investigate the vehicle system dynamic characteristics.The assessment of the operational safety has been conducted by means of characteristic wind curves(CWC).As some of the parameters of the wind-train system were difficult to measure,we also investigated the impact of the uncertain system parameters on the CWC.Results indicate that,the descending order of the operational safety index of the vehicle for each wind angle is 90°-60°-120°-30°-150°,and the worst condition for the operational safety occurs when the wind angle reaches around 90°.According to our findings,the gust factor and aerodynamic side force coefficient have great impact on the critical wind speed.Thus,these two parameters require special attention when considering the operational safety of a railway vehicle subjected to strong gust wind.

The influence of the leading-edge angle of subgrade on the aerodynamic loads of a high-speed train in a wind tunnel

The purpose of this study is to establish the correlation between the boundary layer over the subgrade and the aerodynamic loads act-ing on the train model in conventional wind tunnel tests.Firstly,flow characteristics around the subgrade with different leading-edge angles(15°,30°and 45°)are investigated through the particle image velocimetry(PIV)experimental test method.Then,wind tunnel tests of the aerodynamic performance of a high-speed train are carried out.The results are compared with previous experimental data obtained by moving model tests.Results show that,due to the presence of a boundary layer,the pressure acting on the lower part of the train head decreases,while other locations are not significantly affected.This is the reason for the reduction of the aerodynamic drag and lift on the train.In addition,the reduction effects become more obvious when the thickness of the boundary layer increases.The experimental results obtained could serve as a calibration of aerodynamic forces for wind tunnel tests on high-speed trains.

Analysis on formula principles for“head wind”disease based on apriori and clustering algorithm

Objective:To explore the formula principles for“head wind”disease by data-mining and provide reference for the treatment of“head wind”disease.Methods:Prescriptions for headache from“Dictionary of Traditional Chinese Medicine Prescriptions”were collected,sorted and entered into the“Traditional Chinese Medicine Inheritance System”(V2.5)to analyze the composition principles by the methods of revised mutual information,complex system entropy cluster and unsupervised hierarchical cluster.Results:The herbs with high usage frequency in these prescriptions for“head wind”disease included Chuan-xiong,Bai-zhi,Xi-xin,Fang-feng,Gan-cao,Shi-Gao and Qiang-Huo.Three new prescriptions were obtained based on the composition principles and rules.The first new prescription is composed of Quan-xie,Xiong-huang,Jiang-can,Zhi-chuan-wu and Di-long.The second new prescription is composed of Du-huo,Rou-gui,Ku-shen;Fang-feng,Gao-ben,Qiang-huo.The third new prescription is composed of Fu-zi,Sheng-chuan-wu,Tian-nan-xing,Chuan-xiong,Bai-zhi,Shi-gao.Conclusion:We found that the most of herbs used to treat the“head wind”disease are warm and spicy,mainly belong to diaphoretic herbs,wind-expelling herbs,and dampness-dispelling herbs.In addition,the new prescriptions for infertility mainly focus on eliminating evil,with the characteristics of“eliminating phlegm and turbid”,“dredging the channels and collaterals”,“expelling wind-evil”and“promoting blood circulation”.

考虑激励幅值慢变的卷绕头转子系统动力学建模

卷绕头转子系统结构之间的耦合振动和时频变激励使振动问题十分复杂,为了更准确地研究其动力学特性,根据转子动力学理论,使用有限元方法建立了考虑多盘质量慢变的卷绕头非线性转子系统整机动力学模型,运用Newmark-β数值积分方法对其动力学特性求解,得到仅存在初始不平衡量以及卷装不良带来的激励频率、幅值慢变下的非线性动力学行为。通过分析轴心轨迹、时域波形和幅频特性曲线等结果,发现卷绕头转子系统对因卷装不良引起的激励幅值慢变较为敏感,出现新的频率成分。进一步对比分析了不同节点处的振动频谱,其结果可为卷绕头转子系统动力学设计和故障识别提供一定理论支持。

基于SHAP重要性排序和时空双流的多风场超短期功率预测

针对多风场风功率预测中时空特征提取不充分的问题,提出一种基于空间、时间双流特征提取的功率预测方法。采用沙普利加性解释(SHAP)方法分析原始高维数值天气预报(NWP)中各变量的重要性,选择贡献度高的变量子集作为预测模型输入,降低模型复杂度。构建基于自适应动态邻接矩阵的改进图注意力网络(IGAT)提取多风场的动态空间特征;同时将多头注意力机制(MHA)与时间卷积网络(TCN)结合,加强关键时序特征的学习。使用前馈神经网络输出多风场功率预测结果。以西北某十风场的数据进行案例研究,结果表明所提模型的预测效果优于其他模型。

基于MAGAT的风电场功率缺失数据填充方法

风电场功率数据质量对风电预测具有重要意义。然而,由于人为操作、传感器故障、网络故障或通信拥堵等原因,风电场功率数据容易出现大面积缺失问题。因此,结合多头注意力机制(multi-head attention,MA)和图注意力网络(graph attention network,GAT)构建了MAGAT模型,其中GAT层以异质图的方式刻画及提取风电场已知数据与缺失数据的关联关系,MA层挖掘风电场数据特征与缺失功率数据之间的映射关系,从而实现风电场功率缺失数据的高精度填充。在以我国江苏某风电场运行监测数据为对象的算例分析中,与其他先进填充算法相比,所提方法在不同缺失类型、不同缺失率等多个场景下均具有更好表现,表明所提方法在风电场缺失数据填充任务上的有效性及稳定性。

基于数据挖掘对中药治疗头风病的用药规律分析

目的通过数据挖掘发现中药治疗头风病的用药特点并分析总结其规律,为头风病的治疗提供理论依据及用药参考。方法通过检索式检索知网等数据库中自建库至2022年3月有关于中医药治疗头风病的临床医案并提取相关处方建立Excel数据库,使用IBM SPSS Modeler 18对提取的中药做频数分析、关联规则分析及聚类分析。结果合格文献67篇,共统计处方99个,含87味中药,共使用1276次。川芎的使用率最高为84.85%,其他居于前5位的分别是白芍、甘草、当归、白芷,辛、苦,温为首要性味,归经首归肝经,解表类药物的利用度最高,其次是补虚类及活血化瘀类药物,关联程度较高的主要药对为当归—甘草—川芎、当归—白芷—川芎、柴胡—甘草—川芎、僵蚕—川芎、柴胡—白芷—川芎等。结论中医药治疗头风病,多以活血化瘀、益气养血、平肝熄风为主,主要药物包括川芎、白芍、甘草、当归、白芷、柴胡等。

电视剧《风起陇西》男子首服设计考

电视剧《风起陇西》的男子首服设计种类丰富,具有表意、象征、隐喻等功能,是串联全剧内容的重要线索,因其精良的制作水准而备受关注。文章以电视剧《风起陇西》的首服制作实物为研究对象,主要采用文献研究法,结合考古实物和其他艺术形式的图像,梳理、考辨、比对首服形态。研究认为电视剧《风起陇西》男子首服的结构、形制与运用基本符合历史依据,在追求历史之真的基础上进行了艺术化再创作,重视首服设计在视觉语言层面发挥的重要作用。

Revisiting Tashigang village

If you drive along the winding National Highway 318 for two hours,cross the Mon La Pass at an altitude of 4,742 meters,and keep heading south,past the Lhulang Town,Nyingchi City,surrounded by lush forests,you will arrive at Tashigang Village.From 2017 to 2023,I visited Tashigang three times,witnessing its steady development driven by the national strategy of rural revitalization.

考虑横向风浪干扰的舰船航向稳定性自动控制算法

考虑横向风浪干扰下,舰船进入横摇运动状态易偏离期望航向轨迹,为此,研究考虑横向风浪干扰的舰船航向稳定性自动控制算法。对舰船舵机、横向风浪干扰建模,基于所掌握的舰船舵机控制参数、干扰强度,将期望航向参数输入航向控制器,在基于改进BP-PID算法的航向稳定性自动控制方案下,由改进BP神经网络整定PID控制器参数,输出满足期望航向条件的舵角、舵速调节比例系数、微分系数以及积分系数,调节航向,实现航向稳定性自动控制。实验中,横向风浪干扰下,使用此算法控制舰船航向后,舰船航行时首摇角、横摇角、鳍角均方差明显变小,说明该算法可控制舰船按照期望航向稳定航行。

卷绕头横动拨叉机构对丝饼成型的影响分析

为进一步提升产品效能,分析FDY卷绕头横动拨叉机构的工作原理。根据卷绕头横动拨叉的结构特性的演变过程,分析了TMT卷绕机的两轴两叶型拨叉较其他类型拨叉存在的差异。结合拨叉的设计及运动特点,改变拨叉机构成型板、拔叉叶片及八字形瓷件的定位及尺寸,满足丝饼同卷径增质量的运行条件。生产实践结果表明:所使用的拨叉机构通过相关设计改造及调整相应工艺参数可以达到提升产品运输包装效率和节约能耗的目的。

考虑Miner线性累计损伤的卷绕头疲劳寿命预测

纺织机卷绕头长期振动会产生零件损伤,这种振动损伤会形成线性积累,当前方法对卷绕头的疲劳损伤以固定阈值为主,未考虑损伤积累问题,所以难以准确预测卷绕头的疲劳寿命。因此提出基于Miner线性累计损伤的纺织机卷绕头疲劳寿命预测方法。分析纺织卷绕头的主要结构,并从轴段单元、刚性盘、机匣、支承部件四方面出发,构建卷绕头整体的动力学方程。构建振动方程明确卷绕头的振动受力,结合Miner线性累计损伤理论,构建高速卷绕头的疲劳寿命预测函数,完成纺织机卷绕头疲劳寿命的预测。实验结果表明:这种估计方法的疲劳强度损失值与实际值更为接近,振动位移分析结果更加精准,且疲劳寿命预测误差降低,平均误差仅为1.475%。

自拟芎芷柴胡汤治疗无先兆偏头痛少阳邪郁证临床观察

目的 观察自拟芎芷柴胡汤治疗少阳邪郁型无先兆偏头痛的疗效。方法 将68例少阳邪郁型无先兆偏头痛的患者随机分为治疗组35例和对照组33例。对照组口服盐酸氟桂利嗪胶囊,治疗组口服芎芷柴胡汤。结果 治疗28 d后,治疗组VAS评分、每次发作持续时间、发作次数均低于对照组(P<0.05);治疗组的中医证候积分低于对照组(P<0.05);治疗组总有效率和愈显率均高于对照组(P<0.05)。结论 芎芷柴胡汤治疗少阳邪郁型无先兆偏头痛临床疗效满意,值得推广应用。

Forecasting wind speed using a reinforcement learning hybrid ensemble model:a high-speed railways strong wind signal prediction study in Xinjiang,China

Considering the application of wind-forecasting technology along the railway,it becomes an effective means to reduce the risk of tain more reliable wind-speed prediction results,this study proposes an intelligent ensemble forecasting method for strong winds train derailment and overturning.Accurate prediction of crosswinds can provide scientific guidance for safe train operation.To obalong the high-speed railway.The method consists of three parts:the data preprocessing module,the hybrid prediction module and original wind speed data.Then,Broyden-Fletcher-Goldfarb-Shanno(BFGS)method,non-linear autoregressive network with exoge-the reinforcement learing ensemble module.First,fast ensemble empirical model decomposition(FEEMD)is used to process the prediction models for all the sublayers of decomposition.Finally,Q-learning is utilized to iteratively calculate the combined weights nous inputs(NARX)and deep belief network(DBN),three benchmark predictors with different characteristics are employed to build of the three models,and the prediction results of each sublayer are superimposed to obtain the model output.The real wind speed data of two railway stations in Xinjiang are used for experimental comparison.Experiments show that compared with the single benchmark model,the hybrid ensemble model has better accumacy and robustness for wind speed prediction along the railway.The 1-step forecasting results mean absolute error(MAE),mean absolute percentage error(MAPE)and root mean square error(RMSE)of Q-leaming-FEEMD-BFGS-NARX-DBN in site #1 and site #2 are 0.0894 m/s,0.6509%,0.1146 m/s,and 0.0458 m/s.0.2709%,0.0616 m/s.respectively.The proposed ensemble model is a promising method for railway wind speed prediction.

Assessment of natural frequency of installed offshore wind turbines using nonlinear finite element model considering soil-monopile interaction

A nonlinear finite element model is developed to examine the lateral behaviors of monopiles, which support offshore wind turbines(OWTs) chosen from five different offshore wind farms in Europe. The simulation is using this model to accurately estimate the natural frequency of these slender structures, as a function of the interaction of the foundations with the subsoil. After a brief introduction to the wind power energy as a reliable alternative in comparison to fossil fuel, the paper focuses on concept of natural frequency as a primary indicator in designing the foundations of OWTs. Then the range of natural frequencies is provided for a safe design purpose. Next, an analytical expression of an OWT natural frequency is presented as a function of soil-monopile interaction through monopile head springs characterized by lateral stiffness KL, rotational stiffness KRand cross-coupling stiffness KLRof which the differences are discussed. The nonlinear pseudo three-dimensional finite element vertical slices model has been used to analyze the lateral behaviors of monopiles supporting the OWTs of different wind farm sites considered. Through the monopiles head movements(displacements and rotations), the values of KL, KRand KLRwere obtained and substituted in the analytical expression of natural frequency for comparison. The comparison results between computed and measured natural frequencies showed an excellent agreement for most cases. This confirms the convenience of the finite element model used for the accurate estimation of the monopile head stiffness.