共查询到20条相似文献,搜索用时 109 毫秒
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脉冲激光离散划痕过程中,激光冲击波动态加载及界面破坏在瞬间完成。其所包含的脱粘、裂纹扩展、翘曲、断裂和剥落往往无法分辨。为了准确判断涂层失效的临界点,提出一种利用应变诊析膜基系统失效临界点的方法。利用双面胶作为粘结剂,2024铝合金为基体,304不锈钢箔为涂层构建膜基系统理论模型,采用PVDF贴片传感器技术研究了脉冲激光作用下不同理论模型涂层表面的动态应变。结果表明:脉冲激光作用下,涂层表面的动态应变不断往复变化,最终趋于平衡,整个过程在微秒量级的时间内完成。同时,涂层表面的动态响应与膜基系统界面结合状况有关,膜基系统结合完好时,涂层表面的动态响应时间长,得到的最终应变量小。膜基系统全完脱粘时,涂层表面的动态响应时间短,最终应变量大,膜基系统刚开始脱粘的试样介于两者之间。 相似文献
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对一种具有倾斜表面漂移区SOI LDMOS的制造方法进行了研究,提出了多窗口反应离子刻蚀法来形成倾斜表面漂移区的新技术,建立了倾斜表面轮廓函数的数学模型,TCAD工具的2D工艺仿真证实了该技术的可行性,最终优化设计出了倾斜表面漂移区长度为15μm的SOI LDMOS.数值仿真结果表明,其最优结构的击穿电压可达350 V... 相似文献
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GaN异质结的二维表面态 总被引:8,自引:2,他引:6
提出了氮化物表面强极化电荷产生薄吸附层形成的二维表面态新模型. 从薛定谔方程和泊松方程的自洽计算中得到了新的二维表面态. 计算了不同吸附层能带带阶、厚度和表面势下的表面状态,研究了表面态与异质结构间的关联. 算得的表面能级同实验测量数据相吻合. 用该态模型解释了氮化物产生高密度表面态的原因和深表面能级与较浅的瞬态电流激活能间的矛盾. 相似文献
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Kuan Wang Zhengfeng Zhang Yang Ding Sulan Cheng Biwei Xiao Manling Sui Pengfei Yan 《Advanced functional materials》2023,33(37):2302023
High chemical and mechanical stability of cathode surface are the prerequisites enabling high-performance rechargeable battery. Surface facet is among the surface properties that dictate surface stability and cycling performance, while its underlying mechanism remains elusive. Herein, it is reported that surface stability is closely related to the surface facet for a variety of layered cathodes. The investigation shows that surface structure of P2 layered cathode undergoes sequential transformation upon cycling, which results in severe surface degradation. This study finds that the surface facets perpendicular to the (002) planes experience severe cracking and corrosion, while other surface facets are much more stable. The surface stability difference mainly comes from a geometric effect on strain release, which determines the mechanical stability of surface. Chemically, transition metal condensation forms a passivation layer to effectively prevent the inward propagation of surface degradation. Therefore, the surface facets oblique to the layered-planes are intrinsically more resistant to mechanical cracking and chemical corrosion, which is further verified as a common effect in several O3-type layered cathodes. This work not only deepens the understanding of the mechanism how surface facet affects surface stability, but also validates surface facet regulation can be a promising strategy for optimizing battery materials. 相似文献
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异形曲面构件在航空、航天、船舶等领域应用广泛,其粘接质量成为影响工作安全的重要因素。太赫兹凭借其独特的物理特性,近乎是对聚甲基丙烯酰亚胺(PMI)材料粘接质量进行检测的唯一手段。异形曲面构件上下表面曲率不一致,仅以上表面作为基准曲面进行路径规划时,无法对异形曲面构件粘接质量进行准确判断。对此,在下表面固定不同形状的金属片模拟粘接层中的缺陷,分别以异形曲面构件上下表面为基准曲面,采用机器人化太赫兹时域光谱检测系统进行检测。对上下表面2个基准曲面的太赫兹成像结果进行对比分析,结果表明,以下表面为基准曲面进行检测时,区域Ⅱ、Ⅲ处信号信噪比,较上表面为基准曲面检测时提高12.09 dB、10.39 dB;区域Ⅱ、Ⅲ处金属片实际检测面积与理论面积比值,较上表面为基准曲面检测时提高55.97%、80.81%,更好地满足了异形曲面构件的检测要求。这项工作将促进太赫兹成像在实践中的应用,并为相关领域的进一步研究提供支撑。 相似文献
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A number of experiments are described in which entrance and exit surface laser-induced damage on sapphire samples are studied. Damage thresholds are measured as a function of beam size and divergence at the surfaces. Temporal evolution of surface plasmas is studied using a streaking camera, and spatial differentiation of surface plasmas is accomplished by allowing the light to strike the surfaces away from normal incidence. It is found that the entrance surface has two plasma components, an air plasma that is directed along the light beam and an "explosion" plasma that is directed normal to the surface. The exit surface has only the explosion plasma. It is concluded that surface plasmas are a result rather than a cause of surface damage. 相似文献
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Surface waves due to a current source on a grounded ferrite slab are investigated. Electromagnetic fields of the structure are in terms of a continuous plane wave spectrum. The spectrum of each field component is obtained numerically through the exponential-matrix method. The surface waves of the structure are extracted from the continuous spectrum by using the residue theorem and the method of steepest descent. Two types of surface waves are found and their properties are described. The surface wave modes found include dynamic surface wave modes which are closely related to the surface waves of a grounded dielectric slab, and magnetostatic surface wave modes which are related to the solution of Laplace's equation for the magnetic potential 相似文献
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从红外辐照热平衡方程求解海面温度 总被引:5,自引:0,他引:5
针对海面红外仿真中需要输入实时海面温度的要求,本文从海面的热平衡方程出发,将平衡方程中的各项,如太阳辐射、天空辐射、海面自发射、海面与大气的热交换等用温度的函数表示,然后从平衡方程中解出海面温度,最后模拟了海面温度随太阳辐照、天空辐照、风速、相对湿度的变化,模拟结果表明本计算模型是准确可靠的。 相似文献
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依据地表物体表面外形特性,物体反射分为镜面反射、漫反射和方向反射.探讨了3类反射的特性曲线,介绍了几种典型的地物类型反射波谱特征,并对影响地物光谱反射特性变化的因素进行了概略描述,以加强对地物电磁波谱特征的认知,及开展与高光谱成像领域相关的遥感图像分析、反演和应用等方面的工作. 相似文献
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表面重熔、表面合金化及表面熔覆是铝合金表面激光改质的三个主要方法,各方法都有自已的特点,但又有相关性.通过一系列实验可以对比性地了解这些工艺对铝合金表面组织的影响及强化效果,这将对铝合金激光表面强化新工艺的研究和应用提供参考. 相似文献