Target Controllability of Multi-Layer Networks With High-Dimensional

This paper studies the target controllability of multilayer complex networked systems,in which the nodes are highdimensional linear time invariant(LTI)dynamical systems,and the network topology is directed and weighted.The influence of inter-layer couplings on the target controllability of multi-layer networks is discussed.It is found that even if there exists a layer which is not target controllable,the entire multi-layer network can still be target controllable due to the inter-layer couplings.For the multi-layer networks with general structure,a necessary and sufficient condition for target controllability is given by establishing the relationship between uncontrollable subspace and output matrix.By the derived condition,it can be found that the system may be target controllable even if it is not state controllable.On this basis,two corollaries are derived,which clarify the relationship between target controllability,state controllability and output controllability.For the multi-layer networks where the inter-layer couplings are directed chains and directed stars,sufficient conditions for target controllability of networked systems are given,respectively.These conditions are easier to verify than the classic criterion.

Target layer state estimation in multi-layer complex dynamical networks considering nonlinear node dynamics

In many engineering networks, only a part of target state variables are required to be estimated.On the other hand,multi-layer complex network exists widely in practical situations.In this paper, the state estimation of target state variables in multi-layer complex dynamical networks with nonlinear node dynamics is studied.A suitable functional state observer is constructed with the limited measurement.The parameters of the designed functional observer are obtained from the algebraic method and the stability of the functional observer is proven by the Lyapunov theorem.Some necessary conditions that need to be satisfied for the design of the functional state observer are obtained.Different from previous studies, in the multi-layer complex dynamical network with nonlinear node dynamics, the proposed method can estimate the state of target variables on some layers directly instead of estimating all the individual states.Thus, it can greatly reduce the placement of observers and computational cost.Numerical simulations with the three-layer complex dynamical network composed of three-dimensional nonlinear dynamical nodes are developed to verify the effectiveness of the method.

Multi-layer phenomena in petawatt laser-driven acceleration of heavy ions

Laser-accelerated high-flux-intensity heavy-ion beams are important for new types of accelerators.A particle-in-cell program(Smilei) is employed to simulate the entire process of Station of Extreme Light(SEL) 100 PW laser-accelerated heavy particles using different nanoscale short targets with a thickness of 100 nm Cr, Fe, Ag, Ta, Au, Pb, Th and U, as well as 200 nm thick Al and Ca. An obvious stratification is observed in the simulation. The layering phenomenon is a hybrid acceleration mechanism reflecting target normal sheath acceleration and radiation pressure acceleration, and this phenomenon is understood from the simulated energy spectrum,ionization and spatial electric field distribution. According to the stratification, it is suggested that high-quality heavy-ion beams could be expected for fusion reactions to synthesize superheavy nuclei. Two plasma clusters in the stratification are observed simultaneously, which suggest new techniques for plasma experiments as well as thinner metal targets in the precision machining process.

Damage of multi-layer spaced metallic target plates impacted by radial layered PELE

Three different kinds of PELE(the penetrator with lateral efficiency) were launched by ballistic artillery to impact the multi-layer spaced metal target plates.The lmpact velocities of the projectiles were measured by the velocity measuring system.The damage degree and process of each laye r of target plate impacted by the three kinds of projectiles were analyzed.The experimental results show that all the three kinds of projectiles have the effect of expanding holes on the multi-layer spaced metal target plates.For the normal structure PELE(without layered) with tungsten alloy jacket and the radial layered PELE with tungsten alloy jacket,the diameters of holes on the seco nd layer of plates are 3.36 times and 3.76 times of the diameter of the projectile,re spectively.For radial layered PELE with W/Zr-based amorphous composite jacket,due to the large number of tungsten wires dispersed after the impact,the diameter of the holes on the four-layer spaced plates can reach 2.4 times,3.04 times,5.36 times and 2.68 times of the diameter of the projectile.Besides,the normal structure PELE with tungsten alloy jacket and the radial layered PELE whit tungsten alloy jacket formed a large number of fragments impact marks on the third target plate.Although the number of fragments penetrating the third target plate is not as large as that of the normal structure PELE,the area of dispersion of fragments impact craters on the third target plate is larger by the radial layered PELE.The radial layered PELE with W/Zr-based amorphous composite jacket released a lot of heat energy due to the impact of the matrix material,and formed a large area of ablation marks on the last three target plates.

General series expression of eddy-current impedance for coil placed above multi-layer plate conductor

This paper presents a closed expression of the layered-plate factor used to calculate the coil eddy-current impedance over the multi-layer plate conductor. By using this expression, the general series of eddy-current impedance can be written directly without solving the undetermined constant equations. The series expression is easy to use for theoretical analysis and programming. Experimental results show that calculated values and measured values are in agreement. As an application, when the bottom layer of the layered plate is a non-ferromagnetic thin layer conductor and the product of the thickness and conductivity of the layer remains unchanged, using the layered-plate factor expression proposed in this paper, it can be theoretically predicted that the eddy-current impedance curves corresponding to different thin layer thickness values will coincide.

An Experimental and Numerical Study on the Ballistic Performance of Multi-Layered Moderately-Thick Metallic Targets against 12.7-mm Projectiles

Themain goal of this work is to study the ballistic performance ofmulti-layered moderately-thick metallic targets.Several target configurations have been considered in thiswork,with various types of interlayer connection(spaced,contacted and adhesive)and the number of layers(four and eight),and the influence of target configurations on ballistic performance has been studied experimentally and numerically.In the experiments,the targets were impacted by 12.7-mm projectiles at a velocity around 820 m/s.The experimental results show that,with similar total thickness,the contacted and adhesive targets exhibit better ballistic performance than the monolithic targets,and the four-layered targets are better than the eight-layered targets with the same connection type.To explore the ballistic resistance mechanism,numerical method has been used to simulate the penetration process of each target.The numerical results indicate that petal formation and friction have significant influence on targets’ballistic performance.Friction has stronger influence on themulti-layered targets than on themonolithic ones.According to the numerical results,about 14%of projectile’s initial kinetic energy is dissipated by friction during penetrating the four-layered contacted target,which is proved to be the most effective type of target studied in thiswork.The results also indicate that,in contrast to common understanding,friction plays an important role even when the impact velocity is significantly higher than the ballistic limit.The outcome of this work may provide useful information for a better understanding of ballistic resistant mechanisms and more efficient utilization of multi-layered metallic targets in armor structural design.

Calculation of the heat flux in the lower divertor target plate using an infrared camera diagnostic system on the experimental advanced superconducting tokamak

During the discharging of Tokamak devices, interactions between the core plasma and plasma-facing components (PFCs) may cause exorbitant heat deposition in the latter. This poses a grave threat to the lifetimes of PFCs materials. An infrared (IR) diagnostic system consisting of an IR camera and an endoscope was installed on an Experimental Advanced Superconducting Tokamak (EAST) to monitor the surface temperature of the lower divertor target plate (LDTP) and to calculate the corresponding heat flux based on its surface temperature and physical structure, via the finite element method. First, the temperature obtained by the IR camera was calibrated against the temperature measured by the built-in thermocouple of EAST under baking conditions to determine the true temperature of the LDTP. Next, based on the finite element method, a target plate model was built and a discretization of the modeling domain was carried out. Then, a heat conduction equation and boundary conditions were determined. Finally, the heat flux was calculated. The new numerical tool provided results similar to those for DFLUX;this is important for future work on related physical processes and heat flux control.

Flow Field and Thermal Analysis of the Divertor Target Plate for HL-2A Tokamak

In the initial phase of the physics experiment, the double-null divertor plates used consist of graphite armor tiles, Mo-alloy intermediate layers and Cu-alloy coolant tubes. In the later operating phase, tungsten will be used as armor tiles. A multi-physical field numerical analysis method is used in this paper. Its analysis model reflects more realistically the real divertor structure than other models. Two-dimensional （2D） and three-dimensional （3D） fluid flow field, temperature distribution and thermal stress analyses of the divertor plates are carried out by the ANSYS code. During the physics experimental phase with a heat flux of 1 MW/m2, a coolant velocity of 5.48 m/s, and a thermal stress of 750 kg/cm2, the graphite armor tiles successfully meet the requirements of temperature, thermal stress and sputtering erosion. The tungsten armor will be considered as a second candidate. The result of simulation can be used for upgrading the design parameters of the HL-2A poloidal divertor.

Intelligent Detection Method of Substation Environmental Targets Based on MD-Yolov7

The complex operating environment in substations, with different safety distances for live equipment, is a typical high-risk working area, and it is crucial to accurately identify the type of live equipment during automated operations. This paper investigates the detection of live equipment under complex backgrounds and noise disturbances, designs a method for expanding lightweight disturbance data by fitting Gaussian stretched positional information with recurrent neural networks and iterative optimization, and proposes an intelligent detection method for MD-Yolov7 substation environmental targets based on fused multilayer feature fusion (MLFF) and detection transformer (DETR). Subsequently, to verify the performance of the proposed method, an experimental test platform was built to carry out performance validation experiments. The results show that the proposed method has significantly improved the performance of the detection accuracy of live devices compared to the pairwise comparison algorithm, with an average mean accuracy (mAP) of 99.2%, which verifies the feasibility and accuracy of the proposed method and has a high application value.

基于顶点与主体区域同步检测的精准车牌定位

为应对非约束环境下的车牌精定位问题,提出一种基于顶点局部区域与主体区域同步检测策略的非约束性车牌定位算法。通过删减YOLOv5网络的输出结构,训练得到可同步检测车牌及顶点区域的车牌检测网络,在兼顾精度与计算速度的前提下,实现车牌顶点和主体区域的同步定位。针对一幅图中存在多个车牌区域及顶点区域存在少量漏检和误检的情况,分别设计了车牌顶点归类和单一缺失顶点预测后处理算法,借助顶点间的空间位置关系进行漏检目标预测和误检目标排查,有效改善了因场景复杂导致的个别顶点目标检测效果差的问题。所提算法在中国城市停车场数据集(CCPD)上的测试结果显示,平均精准率达99.25%,平均召回率达98.70%。所提算法不仅能够准确预测出车牌的4个顶点坐标,而且在中端GPU硬件平台上处理速度可达121帧/s,具有较好的应用价值。

基于YOLOv8-OCR的井下人员检测算法

为提高井下昏暗环境的目标检测性能,将行人属性应用到井下,将反光号码牌贴在安全帽和工作服上作为属性进行识别。针对井下小目标检测率低的缺点,提出了一种将YOLOv8检测算法与光学字符识别(Optical Character Recognation, OCR)技术相结合的方法。通过添加卷积块注意力模块(Convolutional Block Attention Module, CBAM),提高了网络对不同尺度的特征提取能力;将YOLOv8中的CBS模块改进为CBF模块,提高了目标的识别准确率;对检测到的反光号码牌区域用OCR技术对区域内数字进行识别,进一步提高了模型的检测精度。实验结果表明,提出的方法在自建数据集上获得了93.2%的识别准确率和每张24.4 ms的检测速度,相比YOLOv8模型有着更高的准确率,能够有效地应对井下环境中的光照变化和干扰因素并且满足实时检测的要求。

层叠型缓冲靶板对弹载测试仪的保护作用研究

使用空气炮模拟火炮发射时的高过载环境对弹载测试仪进行测试时,弹丸撞击靶板会产生尖峰脉冲对测试仪造成严重的损伤,为提高测试仪的存活性,展开对缓冲靶板层叠方式(不同材质的靶板相互叠加的叠层结构)的研究。通过撞击动力学理论描述弹丸对靶板的压缩和侵彻行为,并结合动量守恒和能量守恒定律计算出靶板参数和传递到靶板上的冲量的关系。使用ANSYS/LS-DYNA建立弹丸正侵彻靶板模型,弹丸速度为200 m/s、质量为5.5 kg,仿真结果表明:3层总厚度450 mm的泡沫铝+泡沫铝+橡胶组合方式能有效消除尖峰脉冲并缩短弹丸对靶板的作用时间,加速度均值约为7 000g,脉宽为2.8 ms。受条件限制,空气炮试验采用弹丸质量为5.5 kg、速度为150 m/s,并将缓冲靶板的单层厚度减小到100 mm,结果表明:在泡沫铝+泡沫铝+橡胶组合方式下,弹丸结构和测试仪功能完好,加速度均值约为27 000g,脉宽为0.55 ms。

不同金属镀层单晶硅靶板的冲击受力特性

为了探究金属镀层对单晶硅靶板抗冲击性能的影响,建立了金属/单晶硅复合靶板理论分析模型,分析讨论了单晶硅靶板表面的最大应力与镀层材料动态屈服应力的关系,应用有限元法在LS-DYNA软件中对金属/单晶硅复合靶板进行瞬态动力学计算,得到了不同金属镀层单晶硅靶板冲击受力后的力学响应。根据实验结果总结得到金属镀层对单晶硅靶板冲击受力具有一定的抗冲击效果,能够延迟和减弱出现在靶板正、背面的应力峰值,减小在靶板上产生的应力。

不同基底氘钛靶性能研究

中子发生器的靶片性能影响中子产额和稳定性。为防止钛膜和基底材料间生成合金,进而影响靶片性能,本研究在氘钛靶储氢层与基底层之间采用了镀金工艺,以阻止钛膜和靶片的基底材料相互渗透,进而影响钛膜中钛元素浓度,造成靶上有效氘浓度降低。经过对比测试,钼基底镀金氘钛靶的中子产额可达到1.61×10^(9)s^(−1),在束流强度一定的条件下,其中子产额及稳定性优于铜基底镀金氘钛靶和纯钼基底氘钛靶。电子显微镜能谱分析显示,钼基底镀金氘钛靶中钛元素丰度最高,成功解释了其中子产额较高的原因。同时模拟计算排除了实验中靶片温度上升对靶中氘溢出的影响。此研究为理解和优化中子发生器提供了有价值的见解。

结构间隙对复合靶板抗弹性能的影响

为研究结构间隙对复合靶板抗弹性能的影响,探究弹体与靶板的响应规律,利用有限元软件对4种不同间隙结构的复合靶板在不同弹速冲击下的毁伤变形状态进行仿真分析,得到弹体的剩余速度和靶板各组成部分吸能占比的变化规律。结果表明:结构间隙会影响复合靶板的抗弹性能,在弹体速度相同的情况下,有结构间隙靶板的弹体剩余速度更小;在不同速度段,结构间隙布置在不同位置时发挥的作用是不同的;抗弹芯层在弹体侵彻过程中是吸收弹体动能的主要部分,吸能占比约为58%;靶板间结构间隙能提升靶板的抗弹性能。

非透明纤维集合体的树脂浸透速率测试方法探究

通过对纤维树脂浸透速率的测试方法进行分析,发现靶环法适合测试树脂浸渍后由不透明变透明的纤维集合体的树脂浸透速率,不适合测试树脂浸渍后不变透明的纤维集合体的树脂浸透速率。文章设计了一种基于靶环法改进的非透明纤维树脂浸透速率测试方法—靶盘示踪法。研究结果表明靶盘示踪法测试非透明纤维集合体的树脂浸透速率时,具有测试方法简单、结果稳定的特点。

靶磁场强度对电弧离子镀沉积TiAlSiN硬质涂层内应力的影响

用电弧离子镀制备的TiAlSiN硬质涂层,具有硬度高、致密性好、结合力优良的优点,在刀具工业中有广泛的应用市场。TiAlSiN硬质涂层的内应力不仅会影响涂层的硬度和结合力,也会影响刀具的切削寿命。研究了用电弧制备TiAlSiN涂层过程中,TiSi靶的磁场强度变化对涂层内应力的影响。结果表明,当TiSi靶的磁场从MAG3调为MAG6时,磁场强度减弱,靶材离化率降低,TiAlSiN涂层的内应力从−5.84 GPa降低到−3.16 GPa,而涂层的结合力和硬度几乎没有降低,切削寿命提高了30%。研究为提高TiAlSiN涂层的性能,进而提升刀具的使用寿命提供了有价值的试验数据。

基于图像识别算法的变电站压板核对系统研究

目前变电站压板核对工作需要人工的方式进行现场核对,工作效率低,灵活性和准确性不高。为了解决上述问题,文章通过图像识别算法的技术给核对压板工作提供一种支撑技术手段,搭建变电站压板数据库系统,使用便携式压板核对手持平台,对改进目前的人工纸质表格核对方式问题的解决和突破具有重要意义。

Approximate Design of Alloy Composition of Cathode Target

An empirical formula for composition demixing analysis in cathodic arc ion plating using alloy target is established based on the concepts of average charged state and relative demixing parameter. The level of composition demixing effect is presented by demixing degree of one element. For binary constituent alloy target, the composition change trend in coating is discussed and the limit of demixing degree for each element is determined. The content of one element with higher average charged state gets larger in coating than in alloy target, at meantime, the content of one element with lower average charged state gets less. For each one of the two constituents, the less the atom percent in alloy target, the larger the difference of its contents between the coating and the target. For triple constituent alloy target, the content change of one element with moderate average charged state is discussed in detail. Its content in coating getting larger or less is determined by the combination result of the contents of the other two elements in alloy target. For a given content of the element with moderate average charged state in triple alloy target, the content deviation level of that element from coating to alloy target will be not larger than that using binary alloy target containing only that element and one of the two others. According to the wanted coating composition, the composition design of alloy target is easily deduced from the formula.

An enhanced oil recovery technique by targeted delivery ASP flooding

Aiming at the problem of the loss of the ASP flooding near the injection wells, this paper gives a new idea to enhance oil recovery called "Technique of Targeted Delivery", which combines the radial horizontal well with ultra-short radius drilled by high pressure water jet with the ASP flooding, the horizontal wells work as the "Target channel" transport the ternary composite system to the remaining oil enrichment area directly, to avoid the loss of the ternary composite system near the injection wells. The plate homogeneous experiment and numerical simulation show that the technique can significantly improve the sweep efficiency and the effect of the oil displacement, and greatly improve the oil recovery rate. The optimal flooding parameters of the target transport technique are: the right angle target, the length of the channel is about 15% of the well distance and the injection volume of the ternary composite system is 0.4 PV. Under such conditions, this technique can enhance recovery by 48.87% and 22.04% respectively, compared with the water flooding and conventional ASP flooding. The target transport technique solves the problem of high loss of chemical agent in near-wellbore area during the ASP flooding, and compensates for the high cost of ASP flooding and the limitation of application, and has a broad application prospect.