High-order harmonic generation of ZnO crystals in chirped and static electric fields

High harmonic generation in ZnO crystals under chirped single-color field and static electric field are investigated by solving the semiconductor Bloch equation(SBE). It is found that when the chirp pulse is introduced, the interference structure becomes obvious while the harmonic cutoff is not extended. Furthermore, the harmonic efficiency is improved when the static electric field is included. These phenomena are demonstrated by the classical recollision model in real space affected by the waveform of laser field and inversion symmetry. Specifically, the electron motion in k-space shows that the change of waveform and the destruction of the symmetry of the laser field lead to the incomplete X-structure of the crystal-momentum-resolved(k-resolved) inter-band harmonic spectrum. Furthermore, a pre-acceleration process in the solid four-step model is confirmed.

新能源汽车电驱动系统加载EMC试验平台电力测功机系统的需求及选型

基于生产厂家的需求,对电波暗室新能源汽车电驱动系统加载EMC试验平台存在的问题进行分析,并提出新的设计方案,完成对电力测功机及其相匹配的供电系统和被测件冷却系统的选型。同时,根据试验需求,设计了数据采集与控制系统,并对该平台进行能力验证。结果表明:该系统对在电波暗室的开发具有一定的参考价值,满足生产厂家的试验需求。

数控机床EMC设计和安装规范中的闭合电流通路阻抗原则

在数控机床电气系统中的电磁兼容(EMC)规范中,闭合电流通路阻抗原则是最基本甚至可以说是最重要的原则之一。闭合通路阻抗最小且稳定则可以改善EMC环境。但实践中对此原则的重要性认识是不足的,导致有的解决方法也是错误的。本文对此原则做了详细的理论分析,并以此为理论依据在实践中采取对应的措施被证明是正确有效的。

EMC装配式结构中铝合金模板施工技术

铝合金模板在EMC装配式结构中配置墙、柱、梁、板等构件模板,结合工程实际情况,对EMC装配式结构中连接段进行模板优化,体现了工具化模板的适用性,同时保证了现浇连接区段混凝土成型质量要求,可为同类工程施工提供参考。

EMC6与Apaf-1、Caspase-3在宫颈癌组织中的表达及临床预后意义

目的 探讨宫颈癌中EMC6、Apaf-1和Caspase-3蛋白的表达情况,并分析其与患者临床病理特征和预后的关系。方法 采用免疫组化方法检测宫颈癌及癌旁组织中EMC6、Apaf-1和Caspase-3蛋白的表达,并收集患者的临床病理资料进行分析,Spearman检测变量间的相关性,单因素及多因素Cox分析预后影响因素。结果 EMC6、Apaf-1及Caspase-3蛋白在宫颈癌组织中的阳性表达率均低于癌旁组织,差异有统计学意义(P均<0.05);不同临床病理特征间EMC6蛋白阳性表达率差异无统计学意义(P>0.05);不同分化程度宫颈癌患者中Apaf-1蛋白阳性表达率差异有统计学意义(χ^(2)=4.723,P=0.030);不同临床分期和分化程度宫颈癌患者中Caspase-3蛋白阳性表达率差异有统计学意义(χ^(2)=4.495,P=0.034;χ^(2)=5.010,P=0.025)。EMC6与Apaf-1、Caspase-3相关性系数分别为r=0.626(P<0.001)、r=0.554(P<0.001),均呈正相关;单因素检验得出,病理类型(P=0.047)、肿瘤大小(P<0.001)、EMC6(P=0.004)、Apaf-1(P=0.029)和Caspase-3(P=0.039)是影响宫颈癌患者总体生存期的预后因素;多因素分析显示,EMC6(P=0.005)、肿瘤大小(P<0.001)是宫颈癌患者不良预后的独立影响因素。结论 宫颈癌组织中EMC6、Apaf-1和Caspase-3的低表达与患者预后不良相关,其中EMC6与Apaf-1、Caspase-3呈正相关,且EMC6和肿瘤大小是独立的预后因素,这些蛋白在宫颈癌进展中发挥重要作用,有望成为预后标志物和治疗靶点。

提升电磁兼容性(EMC)检测报告规范性与专业性的分析与建议

电磁兼容性(EMC)是电子电气产品的通用质量指标之一。本文通过分析EMC检测报告中所需的通用要素,梳理EMC检测机构运行过程中的常见风险,分析内外部评审对报告质量抽查中发现的问题,并以集成电路辐射发射检测报告为例,分析了EMC检测报告的主要技术参数和关键点,旨在为提升EMC检测机构质量服务效能,以及EMC检测报告的规范性和专业性提供参考。

Tunable spectral continuous shift of high-order harmonic generation in atoms by a plasmon-assisted shaping pulse

We delve into the phenomenon of high-order harmonic generation within a helium atom under the influence of a plasmon-assisted shaping pulse.Our findings reveal an intriguing manipulation of the frequency peak position in the harmonic emission by adjusting the absolute phase parameter within the frequency domain of the shaping pulse.This phenomenon holds potential significance for experimental setups necessitating precisely tuned single harmonics.Notably,we observe a modulated shift in the created harmonic photon energy,spanning an impressive range of 1.2 eV.This frequency peak shift is rooted in the asymmetry exhibited by the rising and falling edges of the laser pulse,directly influencing the position of the peak frequency emission.Our study quantifies the dependence of this tuning range and the asymmetry of the laser pulse,offering valuable insights into the underlying mechanisms driving this phenomenon.Furthermore,our investigation uncovers the emergence of semi-integer order harmonics as the phase parameter is altered.We attribute this discovery to the intricate interference between harmonics generated by the primary and secondary return cores.This observation introduces an innovative approach for generating semi-integer order harmonics,thus expanding our understanding of high-order harmonic generation.Ultimately,our work contributes to the broader comprehension of complex phenomena in laser-matter interactions and provides a foundation for harnessing these effects in various applications,particularly those involving precise spectral control and the generation of unique harmonic patterns.

EMC预制空心叠合剪力墙施工技术探讨

EMC装配式混凝土结构作为一种新型的装配式建筑技术,在不少建筑中得以应用,但经验总结还较少。本研究首先概述了EMC预制空心叠合剪力墙结构体系、构造特征和技术优势,然后结合实际项目论述了EMC预制空心叠合剪力墙施工技术的施工控制要点,最后从成本和工期角度对比分析了EMC预制空心叠合剪力墙施工技术的实际效益。

EMC模式下城市道路照明LED路灯节能改造研究

近年来,随着现代社会的快速发展,我国各级政府越来越重视城市化形象,这需要投入越来越多的资源、人力和物力,能源消耗也逐年上升,从而导致可开发的资源和能源也越来越稀少,因此寻找正确高效的节能减排方法已迫在眉睫。而在这些城市能源消费中,电力消费是其中非常重要的一部分,尤其是城市路灯消费,虽然满足了群众的生活需要,但同时也造成了能源的浪费。基于此,文章介绍了合同能源管理(EMC)模式,分析路灯节能技术的优势,以及城市亮化和路灯节能技术存在的问题,重点对EMC模式下城市道路照明LED路灯节能改造途径进行探讨。

Terahertz quasi-perfect vortex beam with integer-order and fractional-order generated by spiral spherical harmonic axicon

We propose a new method to generate terahertz perfect vortex beam with integer-order and fractional-order. A new optical diffractive element composed of the phase combination of a spherical harmonic axicon and a spiral phase plate is designed and called spiral spherical harmonic axicon. A terahertz Gaussian beam passes through the spiral spherical harmonic axicon to generate a terahertz vortex beam. When only the topological charge number carried by spiral spherical harmonic axicon increases, the ring radius of terahertz vortex beam increases slightly, so the beam is shaped into a terahertz quasi-perfect vortex beam. Importantly, the terahertz quasi-perfect vortex beam can carry not only integer-order topological charge number but also fractional-order topological charge number. This is the first time that vortex beam and quasi-perfect vortex beam with fractional-order have been successfully realized in terahertz domain and experiment.

THE GRADIENT ESTIMATE OF SUBELLIPTIC HARMONIC MAPS WITH A POTENTIAL

In this paper,we investigate subelliptic harmonic maps with a potential from noncompact complete sub-Riemannian manifolds corresponding to totally geodesic Riemannian foliations.Under some suitable conditions,we give the gradient estimates of these maps and establish a Liouville type result.

Elliptically polarized high-order harmonic generation of Ar atom in an intense laser field

High-order harmonic generation(HHG) of Ar atom in an elliptically polarized intense laser field is experimentally investigated in this work.Interestingly,the anomalous ellipticity dependence on the laser ellipticity(ε) in the lower-order harmonics is observed,specifically in the 13rd-order,which displays a maximal harmonic intensity at ε ≈ 0.1,rather than at ε = 0 as expected.This contradicts the general trend of harmonic yield,which typically decreases with the increase of laser ellipticity.In this study,we attribute this phenomenon to the disruption of the symmetry of the wave function by the Coulomb effect,leading to the generation of a harmonic with high ellipticity.This finding provides valuable insights into the behavior of elliptically polarized harmonics and opens up a potential way for exploring new applications in ultrafast spectroscopy and light–matter interactions.

Interference of harmonics emitted by different tunneling momentum channels in laser fields

By numerically solving the semiconductor Bloch equation(SBEs),we theoretically study the high-harmonic generation of ZnO crystals driven by one-color and two-color intense laser pulses.The results show the enhancement of harmonics and the cut-off remains the same in the two-color field,which can be explained by the recollision trajectories and electron excitation from multi-channels.Based on the quantum path analysis,we investigate contribution of different ranges of the crystal momentum k of ZnO to the harmonic yield,and find that in two-color laser fields,the intensity of the harmonic yield of different ranges from the crystal momentum makes a big difference and the harmonic intensity is depressed from all k channels,which is related to the interferences between harmonics from symmetric k channels.

Optimization of extreme ultraviolet vortex beam based on high harmonic generation

In high harmonic generation(HHG),Laguerre–Gaussian(LG) beams are used to generate extreme ultraviolet(XUV)vortices with well-defined orbital angular momentum(OAM),which have potential applications in fields such as microscopy and spectroscopy.An experimental study on the HHG driven by vortex and Gaussian beams is conducted in this work.It is found that the intensity of vortex harmonics is positively correlated with the laser energy and gas pressure.The structure and intensity distribution of the vortex harmonics exhibit significant dependence on the relative position between the gas jet and the laser focus.The ring-like structures observed in the vortex harmonics,and the interference of quantum paths provide an explanation for the distinct structural characteristics.Moreover,by adjusting the relative position between the jet and laser focus,it is possible to discern the contributions from different quantum paths.The optimization of the HH vortex field is applicable to the XUV,which opens up a new way for exploiting the potential in optical spin or manipulating electrons by using the photon with tunable orbital angular momentum.

宫颈癌组织中EMC6、C-myc及BCL-2的表达和预后

目的通过生信分析,评估EMC6基因在泛癌及宫颈癌中的表达、免疫相关性及诊断价值,并探究EMC6、C-myc、BCL-2蛋白与宫颈癌的相关性及预后。方法分析TCGA和GTEx数据库中EMC6在泛癌和宫颈癌的表达,并利用SangerBox和Timer数据库评估EMC6与免疫相关性,以及ROC评估诊断潜力。通过免疫组化在68例宫颈癌及癌旁组织中检测EMC6、C-myc、BCL-2蛋白表达,分析其与临床病理特征的联系。使用Phi系数法分析相关性,并利用Kaplan-Meier法评估这些蛋白对预后的影响。结果宫颈癌中EMC6表达降低,对免疫浸润有显著影响,且诊断准确性较高(AUC=0.819)。免疫组化显示,与宫颈癌旁组织相比,EMC6蛋白表达下降、而C-myc和BCL-2蛋白表达上调,差异均有统计学意义(P<0.05)。EMC6表达与临床病理特征无相关性(P>0.05),而C-myc与病理类型相关(P<0.05),BCL-2与年龄、病理类型、肿瘤大小、分化程度相关(P<0.05)。EMC6与C-myc、BCL-2表达在宫颈癌中呈负相关(Phi=-0.367,P=0.002;Phi=-0.284,P=0.019),且三者与患者总生存期显著相关(P<0.05)。结论宫颈癌中EMC6蛋白表达下降,与C-myc、BCL-2蛋白表达呈负相关,且这些蛋白的表达水平与患者的总生存期之间存在显著的相关性,提示它们可能作为宫颈癌治疗和预后评估的潜在生物标志物。

Effect of Types and Orders of Electromagnetic Field Finite Element Meshes on Power Communication Harmonic Parameters Calculation Results of Tubular Hydrogenerators

In generator design field,waveform total harmonic distortion(THD)and telephone harmonic factor(THF)are parameters commonly used to measure the impact of generator no-load voltage harmonics on the power communication quality.Tubular hydrogenerators are considered the optimal generator for exploiting low-head,high-flow hydro resources,and they have seen increasingly widespread application in China's power systems recent years.However,owing to the compact and constrained internal space of such generators,their internal magnetic-field harmonics are pronounced.Therefore,accurate calculation of their THD and THF is crucial during the analysis and design stages to ensure the quality of power communication.Especially in the electromagnetic field finite element modeling analysis of such generators,the type and order of the finite element meshes may have a significant impact on the THD and THF calculation results,which warrants in-depth research.To address this,this study takes a real 34 MW large tubular hydrogenerator as an example,and establishes its electromagnetic field finite element model under no-load conditions.Two types of meshes,five mesh densities,and two mesh orders are analyzed to reveal the effect of electromagnetic field finite element mesh types and orders on the calculation results of THD and THF for such generators.

EMC装配式结构中铝合金模板施工技术研究

随着现代建筑行业不断发展,装配式结构作为一种高效、节能、环保的新型建筑模式备受瞩目。由于其快速、精准的安装特点,铝合金模板在装配式结构中扮演着重要角色。该材料具有优异的强度和耐腐蚀性能,能够满足建筑对质量和寿命的要求。此外,铝合金模板还具有良好的加工性能,可根据设计要求进行定制,赋予建筑更多个性化可能。因此,铝合金模板在现代建筑领域有着广泛的应用前景,将对建筑工程质量和效率带来显著提升。

大型设备EMC性能现场评估方法

大型设备由于尺寸过大或供电要求过高无法进入实验室进行电磁兼容(EMC)性能测试,目前大型设备无明确的EMC现场测试标准要求。文章阐述了电磁兼容风险评估技术的分析机理及EMC风险评估理想模型,介绍了EMC风险评估要素识别、分析及EMC风险评价方法。借助电磁兼容风险评估技术可评价大型设备的EMC性能,也有助于大型设备现场测试中发现问题后,借助EMC风险评估技术发现EMC风险点,提出相应的风险减缓措施,以提升大型设备的EMC性能。

Numerical Study of the Vibrations of Beams with Variable Stiffness under Impulsive or Harmonic Loading

The behavior of beams with variable stiffness subjected to the action of variable loadings (impulse or harmonic) is analyzed in this paper using the successive approximation method. This successive approximation method is a technique for numerical integration of partial differential equations involving both the space and time, with well-known initial conditions on time and boundary conditions on the space. This technique, although having been applied to beams with constant stiffness, is new for the case of beams with variable stiffness, and it aims to use a quadratic parabola (in time) to approximate the solutions of the differential equations of dynamics. The spatial part is studied using the successive approximation method of the partial differential equations obtained, in order to transform them into a system of time-dependent ordinary differential equations. Thus, the integration algorithm using this technique is established and applied to examples of beams with variable stiffness, under variable loading, and with the different cases of supports chosen in the literature. We have thus calculated the cases of beams with constant or variable rigidity with articulated or embedded supports, subjected to the action of an instantaneous impulse and harmonic loads distributed over its entire length. In order to justify the robustness of the successive approximation method considered in this work, an example of an articulated beam with constant stiffness subjected to a distributed harmonic load was calculated analytically, and the results obtained compared to those found numerically for various steps (spatial h and temporal τ ¯ ) of calculus, and the difference between the values obtained by the two methods was small. For example for ( h=1/8 , τ ¯ =1/ 64 ), the difference between these values is 17%.

Modulation of High-Order Harmonic Generation from a Monolayer ZnO by Co-rotating Two-Color Circularly Polarized Laser Fields

By numerically solving the two-dimensional semiconductor Bloch equation,we study the high-order harmonic emission of a monolayer ZnO under the driving of co-rotating two-color circularly polarized laser pulses.By changing the relative phase between the fundamental frequency field and the second one,it is found that the harmonic intensity in the platform region can be significantly modulated.In the higher order,the harmonic intensity can be increased by about one order of magnitude.Through time-frequency analysis,it is demonstrated that the emission trajectory of monolayer ZnO can be controlled by the relative phase,and the harmonic enhancement is caused by the second quantum trajectory with the higher emission probability.In addition,near-circularly polarized harmonics can be generated in the co-rotating two-color circularly polarized fields.With the change of the relative phase,the harmonics in the platform region can be altered from left-handed near-circularly polarization to right-handed one.Our results can obtain high-intensity harmonic radiation with an adjustable ellipticity,which provides an opportunity for syntheses of circularly polarized attosecond pulses.