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The multicaloric effect refers to the thermal response of a solid material driven by simultaneous or sequential application of more than one type of external field.For practical applications,the multicaloric effect is a potentially interesting strategy to improve the efficiency of refrigeration devices.Here,the state of the art in multi-field driven multicaloric effect is reviewed.The phenomenology and fundamental thermodynamics of the multicaloric effect are well established.A number of theoretical and experimental research approaches are covered.At present,the theoretical understanding of the multicaloric effect is thorough.However,due to the limitation of the current experimental technology,the experimental approach is still in progress.All these researches indicated that the thermal response and effective reversibility of multiferroic materials can be improved through multicaloric cycles to overcome the inherent limitations of the physical mechanisms behind single-field-induced caloric effects.Finally,the viewpoint of further developments is presented. 相似文献
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全波形激光雷达回波信号建模仿真与分析 总被引:5,自引:1,他引:4
全波形回波信号建模仿真与分析是全波形激光雷达探测技术的一项重要研究内容。针对激光束在目标场景中投影点的获取问题,提出了一种基于激光束空间边界的光线求交快速算法,运算效率高,稳定性好。基于激光雷达信号的时空分布特性,推算出目标场景对信号的响应函数,建立二者的作用过程模型。并针对全回波检测技术中的距离选通探测模式,对目标回波信号与距离选通门限的位置关系进行了分类建模和分析。在研究以上三项关键技术的基础上,构建了全波形激光雷达回波信号仿真系统,仿真实现和分析了不同距离选通门限条件下的全波形回波信号特性,并生成了复杂场景下隐蔽目标的全波形激光雷达数据。 相似文献
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Microstructural and electromagnetic properties of MnO2 coated nickel particles with submicron size 下载免费PDF全文
Nickel particles with submicron size are prepared by using the solvothermal method. These spheres are then coated with a layer of MnO2 using the soft chemical method. The microstructure is characterized by x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Energy x-ray dispersive spectrometry and high-resolution images show that the granular composites have a classical core/shell structure with an MnO2 superficial layer,no more than 10 nm in thickness. The hysteresis measurements indicate that these submicron-size Ni composite powders have small remanence and moderate coercivity. The electromagnetic properties of the powders measured by a vector network analyzer in a frequency range of 2-18 GHz are also reported in detail. 相似文献
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THE INFLUENCE OF Co SUBSTITUTION ON THE MAGNETIC PROPERTIES AND THE GIANT MAGNETO-IMPEDANCE EFFECT OF (Fe1-xCox)84Zr3.5Nb3.5B8Cu1 下载免费PDF全文
The microstructure, magnetic properties and the giant magneto-impedance (GMI) effect of the nanocrystalline (Fe1-xCox)84Zr3.5Nb3.5B8Cu1 ribbons have been studied. With increasing Co concentration, the nanocrystallized grain size and volume fraction of the α-Fe(Co) phase decrease under the same annealing condition, while the coercivity Hc increases from 1.92 A/m at x=0.0 to 30.38 A/m at x=0.8. The effective permeability drops sharply with increasing Co concentration so that the GMI effect goes down. A value of more than 380% for the magneto-impedance(MI) ratio was measured at frequency f=2.5 MHz and the sensitivity can reach 0.9% (A/m)-1 for Fe84Zr3.5Nb3.5B8Cu1 ribbon. When x is equal to 0.8, the MI ratio drops to about 30% and the sensitivity only reaches a value of lower than 0.025% (A/m)-1. The concise analysis in theory is also expounded. 相似文献
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基于改进迭代最近点算法的两视角激光雷达数据配准 总被引:1,自引:0,他引:1
两视角激光雷达数据配准是空地探测遮蔽目标研究领域中的一项重要内容,迭代最近点(ICP)算法为其提供了理论基础,但遮蔽条件下激光雷达数据的复杂性使ICP算法在对应点确定上面临很大困难。在分析ICP算法基本原理和遮蔽条件下激光雷达数据特点的基础上,从控制点选择、对应点匹配和伪点对剔除三个方面给出了ICP算法的具体应用策略和改进措施,并提出一种基于固定-自适应重叠率的伪点对剔除方法。详细阐述了基于改进ICP算法的两视角激光雷达数据配准的具体步骤,并进行了实验验证。实验结果表明:改进后的ICP算法能够有效实现了遮蔽条件下的激光雷达数据配准,且与其他算法相比,具有较强的稳建性和较高的配准精度。 相似文献
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针对自动目标识别(Automatic Target Recognition,ATR)系统评价中存在的性能建模手段难以有效分析因素变化对系统性能作用的情况,提出了一种新的因素作用测算方法。该方法根据工作条件下ATR实验结果所具有的面板数据特点,基于Malmquist指数对因素变化进行定量度量,无需对ATR系统的代价进行严格限定。求解过程中采用了非参数的DEA方法计算距离函数,避免了对ATR性能随因素变化趋势的模型假设,并通过引入AHP约束锥实现了多指标情况下的权重限制。最后,通过一个应用实例说明如何运用该评价方法实现因素作用的测算与分析。 相似文献
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