Effect of power supply parameters on discharge characteristics and sterilization efficiency of magnetically driven rotating gliding arc

Plasma sterilization is a new generation of high-tech sterilization method that is fast,safe,and pollution free.It is widely used in medical,food,and environmental protection fields.Home air sterilization is an emerging field of plasma application,which puts higher requirements on the miniaturization,operational stability,and operating cost of plasma device.In this study,a novel magnetically driven rotating gliding arc(MDRGA)discharge device was used to sterilize Lactobacillus fermentation.Compared with the traditional gas-driven gliding arc,this device has a simple structure and a more stable gliding arc.Simulation using COMSOL Multiphysics showed that adding permanent magnets can form a stable magnetic field,which is conducive to the formation of gliding arcs.Experiments on the discharge performance,ozone concentration,and sterilization effect were conducted using different power supply parameters.The results revealed that the MDRGA process can be divided into three stages:starting,gliding,and extinguishing.Appropriate voltage was the key factor for stable arc gliding,and both high and low voltages were not conducive to stable arc gliding and ozone production.In this experimental setup,the sterilization effect was the best at 6.6 kV.A high modulation duty ratio was beneficial for achieving stable arc gliding.However,when the duty ratio exceeded a certain value,the improvement in the sterilization effect was slow.Therefore,considering the sterilization effect and energy factors comprehensively,we chose 80%as the optimal modulation duty ratio for this experimental device.

Data-driven modeling on anisotropic mechanical behavior of brain tissue with internal pressure

Brain tissue is one of the softest parts of the human body,composed of white matter and grey matter.The mechanical behavior of the brain tissue plays an essential role in regulating brain morphology and brain function.Besides,traumatic brain injury(TBI)and various brain diseases are also greatly influenced by the brain's mechanical properties.Whether white matter or grey matter,brain tissue contains multiscale structures composed of neurons,glial cells,fibers,blood vessels,etc.,each with different mechanical properties.As such,brain tissue exhibits complex mechanical behavior,usually with strong nonlinearity,heterogeneity,and directional dependence.Building a constitutive law for multiscale brain tissue using traditional function-based approaches can be very challenging.Instead,this paper proposes a data-driven approach to establish the desired mechanical model of brain tissue.We focus on blood vessels with internal pressure embedded in a white or grey matter matrix material to demonstrate our approach.The matrix is described by an isotropic or anisotropic nonlinear elastic model.A representative unit cell(RUC)with blood vessels is built,which is used to generate the stress-strain data under different internal blood pressure and various proportional displacement loading paths.The generated stress-strain data is then used to train a mechanical law using artificial neural networks to predict the macroscopic mechanical response of brain tissue under different internal pressures.Finally,the trained material model is implemented into finite element software to predict the mechanical behavior of a whole brain under intracranial pressure and distributed body forces.Compared with a direct numerical simulation that employs a reference material model,our proposed approach greatly reduces the computational cost and improves modeling efficiency.The predictions made by our trained model demonstrate sufficient accuracy.Specifically,we find that the level of internal blood pressure can greatly influence stress distribution and determine the possible related damage behaviors.

Effects of counter-current driven by electron cyclotron waves on neoclassical tearing mode suppression

Through theoretical analysis,we construct a physical model that includes the influence of counter-external driven current opposite to the plasma current direction in the neoclassical tearing mode(NTM).The equation is used with this model to obtain the modified Rutherford equation with co-current and counter-current contributions.Consistent with the reported experimental results,numerical simulations have shown that the localized counter external current can only partially suppress NTM when it is far from the resonant magnetic surface.Under some circumstances,the Ohkawa mechanism dominated current drive(OKCD)by electron cyclotron waves can concurrently create both co-current and counter-current.In this instance,the minimal electron cyclotron wave power that suppresses a particular NTM was calculated by the Rutherford equation.The result is marginally less than when taking co-current alone into consideration.As a result,to suppress NTM using OKCD,one only needs to align the co-current with a greater OKCD peak well with the resonant magnetic surface.The effect of its lower counter-current does not need to be considered because the location of the counter-current deviates greatly from the resonant magnetic surface.

Research on the Microstructure Construction Technology of Fully Degraded Polymer Vascular Stent Based on Electric Field Driven 3D Printing

The so-called fourth-generation biodegradable vascular stent has become a research hotspot in thefield of bioengineering because of its good degradation ability and drug-loading characteristics.However,the preparationof polymer-degraded vascular stents is affected by known problem such as poor processflexibility,low formingaccuracy,large diameter wall thickness,limited complex pore structure,weak mechanical properties of radial support and high process cost.In this study,a deposition technique based on a high-voltage electric-field-driven continuous rotating jet is proposed to fabricate fully degraded polymer vascular stents.The experimental results showthat,due to the rotation of the deposition axis,the deposition direction of PCL(polycaprolactone)micro-jet isalways tangent to the surface of the deposition axis.The direction of the viscous drag force is also consistent withthe deposition direction of the jet.It is shown that by setting different rotation speeds of deposition axisωandlinear motion speeds of the nozzle V,the direction of rotation,pitch and angle of the individual printed spiralcurve can be precisely tuned.In the process of multiple spiral curves matching the deposition forming thin walltube mesh,the mesh shape and size of the thin wall tube can be accurately controlled by changing the number ofmatching spiral curves and the size of the matching position bias distance.Finally,the characteristics of a PCLtubular stent sample(with uniform-size microfibers and mesh shape),fabricated under the appropriate processparameters are described in detail.

Data-model coupling driven stress field measurements

This paper presents a method for measuring stress fields within the framework of coupled data models,aimed at determining stress fields in isotropic material structures exhibiting localized deterioration behavior without relying on constitutive equations in the deteriorated region.This approach contributes to advancing the field of intrinsic equation-free mechanics.The methodology combines measured strain fields with data-model coupling driven algorithms.The gradient and Canny operators are utilized to process the strain field data,enabling the determination of the deterioration region's location.Meanwhile,an adaptive model building method is proposed for constructing coupling driven models.To address the issue of unknown datasets during computation,a dataset updating strategy based on a differential evolutionary algorithm is introduced.The resulting optimal dataset is then used to generate stress field results.Validation against finite element method calculations demonstrates the accuracy of the proposed method in obtaining full-field stresses in specimens with local degradation behavior.

Investigation of system parameters towards safer impact based shock-to-detonation transition in a novel laser driven flyer plate prototype

Laser driven flyer plate technology offers improved safety and reliability for detonation of explosives in industrial applications ranging from mining and stone quarrying to the aerospace and defense industries.This study is based on developing a safer laser driven flyer plate prototype comprised of a laser initiator and a flyer plate subsystem that can be used with secondary explosives.System parameters were optimized to initiate the shock-to-detonation transition(SDT)of a secondary explosive based on the impact created by the flyer plate on the explosive surface.Rupture of the flyer was investigated at the mechanically weakened region located on the interface of these subsystems,where the product gases from the deflagration of the explosive provide the required energy.A bilayer energetic material was used,where the first layer consisted of a pyrotechnic component,zirconium potassium perchlorate(ZPP),for sustaining the ignition by the laser beam and the second layer consisted of an insensitive explosive,cyclotetramethylene-tetranitramine(HMX),for deflagration.A plexiglass interface was used to enfold the energetic material.The focal length of the laser beam from the diode was optimized to provide a homogeneous beam profile with maximum power at the surface of the ZPP.Closed bomb experiments were conducted in an internal volume of 10 cm^(3) for evaluation of performance.Dependency of the laser driven flyer plate system output on confinement,explosive density,and laser beam power were analyzed.Measurements using a high-speed camera resulted in a flyer velocity of 670±20 m/s that renders the prototype suitable as a laser detonator in applications,where controlled employment of explosives is critical.

Data Driven Vibration Control:A Review

With the ongoing advancements in sensor networks and data acquisition technologies across various systems like manufacturing,aviation,and healthcare,the data driven vibration control(DDVC)has attracted broad interests from both the industrial and academic communities.Input shaping(IS),as a simple and effective feedforward method,is greatly demanded in DDVC methods.It convolves the desired input command with impulse sequence without requiring parametric dynamics and the closed-loop system structure,thereby suppressing the residual vibration separately.Based on a thorough investigation into the state-of-the-art DDVC methods,this survey has made the following efforts:1)Introducing the IS theory and typical input shapers;2)Categorizing recent progress of DDVC methods;3)Summarizing commonly adopted metrics for DDVC;and 4)Discussing the engineering applications and future trends of DDVC.By doing so,this study provides a systematic and comprehensive overview of existing DDVC methods from designing to optimizing perspectives,aiming at promoting future research regarding this emerging and vital issue.

磁驱动固体套筒实验模拟中的电流系数

采用不可压缩理论模型,对FP-2装置上开展的磁驱动固体套筒实验进行了模拟分析。模拟结果表明,无论是二维磁流体力学理论模型,还是其他不可压缩理论模型,回流罩结构磁驱动固体套筒的边界磁感应强度公式中都包含一个小于1的套筒电流系数。对不同套筒厚度、不同套筒半径条件下磁驱动固体套筒实验的电流系数进行了模拟,发现电流系数不仅与套筒内半径有关,还与套筒厚度有关;套筒内半径越大,套筒电流系数越小;套筒厚度越大,套筒电流系数越小。准确掌握磁驱动固体套筒电流系数的变化规律,可使磁流体程序从磁驱动固体套筒实验的后验模拟发展为精确预测,使磁流体力学模型真正具备正确设计和指导磁驱动固体套筒相关实验的理论能力。

基于简易冲击分解模型的爆轰驱动硅橡胶数值模拟及实验解读

为了反映爆轰驱动下硅橡胶发生冲击分解反应的物理过程,提出了一种简易的硅橡胶冲击分解模型。基于该模型,对爆轰驱动含硅橡胶夹层钢板实验进行了模拟,并分析解读了钢板的自由面速度。结果表明,实验中硅橡胶发生了冲击分解反应,导致钢板的自由面速度曲线出现了首次起跳中间速度平台及首次起跳速度峰值降低的现象。受硅橡胶冲击分解影响,首次入射波压力将在临界冲击分解压力附近弛豫一段时间,再继续升高至最高压力。该压力波作用于钢板的自由面后,出现了自由面速度在中间速度平台停留一段时间,之后继续升高至速度峰值的现象。硅橡胶冲击分解后的气相物质可压缩性较高,首次加载波内较多的能量被用于压缩气体做功,导致首次波传播至自由面时能量衰减,峰值压力降低,首次起跳速度峰值降低。

轮毂电动机驱动车辆并联式复合制动策略

基于并联式轮毂电动机驱动实车构型,分析影响制动能量回收效率的主要因素,采用联邦卡尔曼滤波纵向车速估计算法,提出了三层式复合制动控制策略.该策略中的制动决策层根据踏板输入信号和行驶状态来识别制动工况,并进入相应的制动模式.制动控制层根据制动决策层的指令,在常规制动工况下通过粒子群优化(PSO)算法优化前、后轮电制动力矩分配,实现电池有效回收效率最大化;紧急制动工况下,通过模糊自整定PID算法实现车辆在不同附着路面上各轮滑移率的安全有效控制,优化了制动防抱死控制的鲁棒性,提高制动安全性.制动执行层响应制动控制层的指令,设计了电制动补偿机制,以迅速补偿调节各轮轮缸的压力误差,提高车辆制动稳定性.最后实车验证了该复合控制策略的有效性.

自驱动双关节模组同步控制系统研究

针对自驱动关节臂测量机双关节模组的双电机同步控制问题,根据双关节模组的组成结构和工作原理设计了一种双关节模组同步控制系统。该系统采用LabVIEW软件搭建双电机的上位机控制界面,主控制器为FPGA,两者通过USB串口通信;STM32为双关节模组内部的核心处理器,通过CAN总线与主控制器通信。通过设定不同的负载和速度进行了正反转对比实验,得到双关节模组电机最大转速误差为4.26%,关节转角的最大误差为0.25°,两电机同步时间控制精度为2 ms,验证了双关节模组在负载状态下仍满足技术指标要求,为提高传动精度提供了依据。

Material driven workability simulation by FEM including 3D processing maps for magnesium alloy

The three-dimensional （3D） processing maps considering strain based on the two-dimensional （2D） processing maps proposed by PRASAD can describe the distribution of the efficiency of power dissipation and flow instability regions at various temperatures, strain rates and strains, which exhibit intrinsic workability related to material itself. Finite element （FE） simulation can obtain the distribution of strain, strain rate, temperature and die filling status, which indicates state-of-stress （SOS） workability decided by die shape and different processing conditions. On the basis of this, a new material driven analysis method for hot deformation was put forward by the combination of FE simulation with 3D processing maps, which can demonstrate material workability of the entire hot deformation process including SOS workability and intrinsic workability. The hot forging process for hard-to-work metal magnesium alloy was studied, and the 3D thermomechanical FE simulation including 3D processing maps of complex hot forging spur bevel gear was first conducted. The hot forging experiments were carried out. The results show that the new method is reasonable and suitable to determine the aoorooriate nrocess narameters.

基于北斗测速的电驱式小麦播种机监控系统设计与试验

针对当前小麦播种机智能化程度低、播种作业时种子漏播肥料堵塞导致缺苗断垄现象产生的问题,设计了一款基于北斗测速的电驱式小麦播种机监控系统。通过电容检测可以实时监测小麦种子漏播情况,通过光电检测可以实时监控排肥管内肥料堵塞情况;北斗卫星实时定位并计算出播种机的前进速度,控制器根据播种机前进速度实时调节播种施肥电机转速,实现种子漏播、肥料堵塞报警和精量播种施肥的目的。在田间试验中,装载监控系统的播种机各项性能表现良好,漏播检测准确率91%以上,肥料堵塞检测准确率95%以上,播种合格率平均值大于94.6%,漏播指数小于2.8%,重播指数小于3%,均匀度变异系数小于3.5%,能够满足小麦精量播种的要求。

基于EDEM的驱动耙旋耕装置的分析与试验

为提高动力驱动耙碎土过程中的效率和碎土率,在现有结构基础上,分析了动力耙耙刀碎土原理,构建了碎土耙刀-土壤动力学模型,并对动力驱动耙刀具长度和角度进行设计。同时,利用EDEM软件以动力驱动耙耙刀转动速度、耙刀外倾角度、耙刀长度为影响因素,以碎土率为检测指标,进行响应面仿真分析试验。试验结果表明:耙刀转动速度对碎土率影响极显著,耙刀外倾角和长度对碎土率影响比较显著;耙刀倾角为34.7°、耙刀转速为320 r/min、耙刀长度为28 cm时,耙刀装置处于最优工作状态。研究结果可为动力驱动耙的开发研究提供参考。

ARCHITECTURE OF DYNAMIC DATA DRIVEN SIMULATION FOR WILDFIRE AND ITS REALIZATION

Dynamic data driven simulation （DDDS） is proposed to improve the model by incorporaing real data from the practical systems into the model. Instead of giving a static input, multiple possible sets of inputs are fed into the model. And the computational errors are corrected using statistical approaches. It involves a variety of aspects, including the uncertainty modeling, the measurement evaluation, the system model and the measurement model coupling ,the computation complexity, and the performance issue. Authors intend to set up the architecture of DDDS for wildfire spread model, DEVS-FIRE, based on the discrete event speeification （DEVS） formalism. The experimental results show that the framework can track the dynamically changing fire front based on fire sen- sor data, thus, it provides more aecurate predictions.

区域一体化与企业数字化转型——基于市场竞争和创新驱动的视角

通过以长三角区域一体化试点政策为准自然实验,利用2008—2021年沪深A股上市企业的数据,考察了区域一体化政策对企业数字化转型的影响和内在机理。研究发现,区域一体化政策能够显著提升企业数字化水平,该结论在稳健性检验后仍然成立。从不同维度来看,区域一体化政策显著促进了数字技术发展的深度(底层数字技术应用)和融合发展的广度(智能制造和互联网商业模式)。机制检验表明,区域一体化政策改善了宏观层面的市场竞争环境和创新环境,从而增强了企业面临的赶超压力和驱动企业进行创新策略调整,进而提升企业数字化水平。异质性分析表明,区域一体化政策的数字化发展效应主要存在于国有企业、成长型企业、数字金融发展水平高和知识产权保护重视程度高的地区。进一步研究显示,区域一体化政策不仅促进了企业专业化分工,同时改善了企业资源错配。研究结论不仅为化解企业数字化转型困境提供了经验证据,也为政府深入推进区域一体化协调发展和构建统一大市场提供参考。

场驱动医疗微机器人:材料制备工艺不断优化的应用前景

背景:微机器人具有体积小、灵活、靶向性强等特点,可以在狭窄的环境下通过单体或集群的方式完成复杂的工作。随着材料、制备工艺以及驱动方式的不断优化,其在生物医学领域内显示出越来越重要的应用价值。目的:分析场驱动微机器人在生物医学领域的应用并展望其应用前景。方法:以“微机器人,纳米机器人,驱动,生物医学,医疗”为中文关键词,以“microrobots,micro-robots,nanorobots,micromachine,microswimmer,medical”为英文关键词,分别检索万方以及Pub Med数据库,检索时间范围重点为2010年1月至2024年1月,同时纳入少数远期文献。通过阅读文题、摘要初步筛选,排除重复性研究、低质量期刊以及与内容不相关的文献,阅读全文后最终纳入66篇文献进行综述。结果与结论:场驱动医疗微机器人涵盖了磁、光、热、超声及多种混合因素驱动机器人。场驱动机器人已被应用于肠道诊断、药物靶向治疗及干细胞治疗等多个领域。尽管医用微机器人在临床医学中已有少数应用,但大多数还处于理论和实验阶段。医用微机器人的未来面临诸多挑战,如实现大规模制备、进一步提升精确控制、解决回收或体内降解问题,以及所用材料是否会对人体产生不良反应等,此外微机器人还需与相应的微创医学手术相配合。

艺术乡建背景下乡村街巷环境色彩协调性研究——以广州市大岭村为例

在艺术乡建过程中,因忽视更新色彩与原乡村环境色彩的协调性,乡村色彩渐趋杂乱。本研究以广州市大岭村街巷为例,基于色彩调和理论及相关原理,运用聚类算法计算实地拍摄图像的色彩构成,构建评价方法以判断更新色彩与原乡村环境色彩是否协调并提供优化方向。研究结论为:(1)大岭村艺术乡建前,自体发挥下的更新色彩在色相上更贴合原环境;而艺术乡建后,在规划指导下更新色彩较突兀,产生负面影响较大的是大面积彩绘墙面的方式,该方式的适用性需加以研究。(2)大岭村色彩丰富,但强对比的更新色彩使原环境暗淡,不利于保护乡村原始风貌。本研究拓展了色彩调和理论的应用范围,以期为乡村色彩更新提供方法参考及优化指导。

生育支持与欠发达地区育龄女性的生育意愿——基于贵州省88个区县的生育意愿调查

生育支持已经成为强化青年生育意愿和生育行为的重要举措,然而受限于研究数据,以往的研究很少对欠发达地区各类生育支持及其效果进行研究。为了研究欠发达地区各类生育支持对育龄女性生育意愿的作用,基于贵州省88个区县的生育意愿调查数据,从政府政策支持、社会托育支持和家庭代际支持三个维度研究了生育支持对欠发达地区育龄女性生育意愿的影响。研究发现:(1)当前贵州育龄女性的生育意愿已经下降到了较低水平,未来生育水平有进一步下降的风险。(2)家庭代际支持、社会托育支持和政府政策支持对育龄女性的总体生育意愿都具有显著的促进作用,但只有政府政策支持和家庭代际支持对三孩生育意愿具有显著的影响,社会托育支持对三孩生育意愿的影响不显著。(3)异质性分析则发现各类生育支持对35岁以上的育龄女性影响较大,是对35岁以下年轻群体影响的两倍左右。各类支持对不同学历育龄女性的影响也出现了分化,总体上呈现出低学历女性受到家庭支持与政府政策支持影响较大,而高学历女性受到托育服务影响较大的特征。(4)各类生育支持方式对育龄女性生育意愿的协同效应十分显著,当各类生育支持都较强时,对育龄女性生育意愿的影响较大。基于上述结论,一方面,生育支持体系与生育支持政策既要坚持普惠性,又要兼顾不同群体差异化需求;另一方面,需要进一步完善生育支持体系,充分发挥各类生育支持的协同效应,让育龄女性在生育决策时有更多生育支持方式的选择。

基于数据和模型双重驱动的供应链管理案例研究方法

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