共查询到20条相似文献,搜索用时 375 毫秒
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一、引言 文献1中用波长为0.53μm,脉宽为35ps的激光脉冲作泵浦源,以对称激励的形式,研究了透明以及可饱和吸收介质的筒并四波混频(DFwM)中后向相位共轭波能量E与读出光束相对于写入光束延迟到达非线性介质的时间△t之间的关系, 相似文献
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多尺度复杂电子系统的电磁场问题难以用单一的计算电磁学方法进行高效数值计算.基于区域分解方法和惠更斯等效原理,提出了频域广义传输矩阵(generalized transition matrix,GTM)方法:将系统分解为多个子模块,通过电场积分方程(electric field integreal equation,EFIE)把各个子模块的电磁特性进行提炼,再考虑所有子模块之间的电磁耦合,计算系统整体电磁场分布.GTM方法把多尺度问题转化为尺度相对比较单一的问题进行处理,在分析各种复合结构、非均匀各向异性介质、大型相控阵天线等电磁散射特性时,提供了灵活的解决方案.论文给出了GTM在手征介质、开口腔体以及Vivaldi相控阵天线电磁特性分析中的应用算例,当未知量个数压缩到原来的十分之一时,GTM计算结果与直接用矩量法(methed of moment,MoM)求解的计算结果非常吻合.GTM可以简洁地表示目标问题的电磁散射特征,与传统MoM相比,大幅度减少了基函数的数量,具有较高的计算精度和效率. 相似文献
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Super-RENS超分辨光存储实验研究 总被引:2,自引:2,他引:0
实验在基于传统相变光盘(CD-R/W)的测试系统上进行。在一定的写入功率和脉宽条件下对super-RENS样片进行静态记录,并和传统CD-R/W作对比实验,用扫描电镜(SEM)观察两种盘结构上的记录点,从微观形貌、尺寸参数等方面进行深入研究比较。实验结果表明,使用相同的记录系统和在完全相同的写入条件下,super-RENS上的记录符小于CD-R/W上的记录符,尺寸减小可达40%。 相似文献
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已研制出一种用于编码数据存储的袖珍式磁光光盘,其存储容量是13.34cm(5.25in)软塑料磁盘的500倍。由于采用了先进的高灵敏偏振光捡测光学系统和高质量记录介质,获得了较低的误码率。这方面的进展是通过读出信号噪声进行分析而取得的。该光盘驱动装置既可以通过址码段写入和擦除数据,它还可以用作为现行的一次性写入型光盘。这种光盘/光盘驱动装置可以提高存储容量,因而它可以提高办公系统自动化和其它信息系统的性能。 相似文献
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本文利用脉冲斑模型,分析在光盘存储过程中,光学系统的各种因素,如光功率起伏,光束高斯参数,物镜数值孔径,系统像差及伺服误差等,对所记录信息斑点的影响,结合读出信噪分析,给出了写入光学头的像差容限和伺服要求。 相似文献
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根据潜艇水下腐蚀相关电磁信号的产生机理,该文提出可采用由电偶极子首尾相接而成的电流线对其进行模拟。分别采用边界元建模及电流线建模方法对潜艇模型的水下静态电场进行计算,对比分析结果表明,将电流线作为对潜艇水下腐蚀相关静态电磁信号进行估算的数学模型是可行的。在此基础上,结合分层导电媒质中水平直流电偶极子的磁场表达式,对潜艇腐蚀相关静态磁场在全空间中的分布特征进行了仿真分析。结果表明,空气中潜艇腐蚀相关静态磁场近场量值可测,分布特征明显,可用于航空探潜;海水中潜艇腐蚀相关静态磁场远场按距离的平方反比衰减,可用于消磁潜艇的远程探测。分析所得典型结论为进一步的应用研究奠定了基础。 相似文献
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Electro-chemical mechanical planarization (ECMP) process dissolves copper ions electrochemically by applying an anodic potential on the copper surface in an aqueous electrolyte, and then removes a copper (Cu) complex layer by the mechanical abrasion of a polishing pad or abrasives in the electrolyte. The ECMP process is a low pressure polishing method for metals such as copper, aluminium (Al) and tungsten (W) on dielectric materials such as silicon dioxide, low-k (LK) and ultra low-k (ULK) dielectrics, comparing to the amount of defects by the traditional Cu chemical mechanical planarization (CMP). The polishing pad used in the ECMP process is a conventional closed cell type pad (IC 1400 K-groove pad) with holes. It supplies the aqueous electrolyte to the copper surface and removes the copper complex layer. The material removal rate (MRR) and MRR profile were simulated and tested according to the changes of the wafer overhang distance (WOD) from the platen and the electric contact area (ECA). In order to derive the design rule of the system, the experimental results are compared with the simulation results. After the ECMP process, it was verified that the within wafer non-uniformity (WIWNU) was lower than 2% using the relatively uniform ECA pad (C-type) under the smallest WOD condition. The experimental results well matched the simulated results. 相似文献
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非晶硒对X射线响应特性的理论研究 总被引:1,自引:0,他引:1
较为全面地考查了非昌硒对X射线的灵敏度。引入一个灵敏度模型,在灵敏度与载流子迁移特性、光子能量、非晶硒厚度和场强之间建立了明确的关系。计算结果表明,载流子迁移长度至少应是非晶硒厚度的2倍以上,才能使X射线激发的电子、空穴有较大的概率到达收集电极(或非晶硒自由表面)(即信号收集效率);用加大非晶硒厚度的方法增加灵敏度时必须考虑信号收集效率降低的负面影响;场强对灵敏度有重要影响,提高场强可使非晶硒灵敏 相似文献
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Low-temperature photoluminescence measurements were performed on InAsP/InP strained quantum wells grown on InP (lll)B substrates
by gas-source molecular beam epitaxy. The emission energy was observed to increase as the pump-power density increased. This
was attributed to the screening of the internal piezoelectric field by photo-generated carriers. The energy shift was as large
as 35 meV for an InAs0.28P0.72/InP quantum well with a lattice mismatch of ~0.9%. A similar structure with a smaller strain showed saturation of the energy
shift with increasing pump-power density. We performed a model calculation which includes the quantum confined Stark effect,
and this saturation was correlated with a flat-band structure of the quantum well due to the nearly complete screening of
the built-in electric field. 相似文献
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A finite-element method (FEM) is developed for the analysis of complex axisymmetric radiating structures. The method is based on the electric field formulation with the transverse field expanded in terms of edge-based vector basis functions and the azimuth component expanded using nodal-based scalar basis functions. This mixed representation of the electric field eliminates spurious solutions and permits an easy treatment of boundary conditions on conducting surfaces as well as across material interfaces. The FEM mesh is truncated using a previously developed cylindrical perfectly matched layer (PML). The method has been successfully applied to three radiating structures: a corrugated horn antenna, a spherical Luneburg lens, and a half Maxwell fish eye. Numerical results are presented to show the validity, accuracy, and efficiency of the method 相似文献
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Compositionally graded HgCdTe photodiodes: Prediction of spectral response from transmission spectrum and the impact of grading 总被引:3,自引:0,他引:3
We have studied the infrared transmission spectrum and the optical performance of HgCdTe photodiodes containing a linear composition
gradient in the active layer. Our objectives were to enable the prediction of the optical performance of a photodiode at 77K,
based on the easily and nondestructively measured transmission spectra, as well as to gain a better understanding of the effects
of the grading on the optical performance. Consequently, we address three issues here. We first establish improved characterization
techniques that can provide accurate values of the necessary material parameters such as gradient in composition. Second,
we present a model that can predict the optical response of a diode, based on the material properties and the diode’s geometry.
Third, we use the above-mentioned model for the theoretical calculations of the effects of the grading and the resulting built-in
electric field on the diode’s optical response. 相似文献
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在超分辨光存储技术中,掩膜层材料是决定其性能优劣的关键。In薄膜可以作为掩膜层用来实现超分辨信息点的动态读出。采用直流磁控溅射法制备不同厚度的In薄膜,用台阶仪测量薄膜厚度随时间的变化关系,用原子力显微镜观察不同厚度薄膜样品的表面形貌。在预刻有尺寸为390nm信息点的光盘盘基上制备In薄膜,从而形成In掩膜超分辨光盘。利用光盘动态测试仪进行动态读出,最高读出载噪比(CNR)达到26dB。为了进一步分析超分辨动态读出的物理机理,采用变温椭圆偏振光谱仪测量In薄膜在不同温度下的光学常数,得到In薄膜在不同温度下的反射率和吸收系数。分析表明In掩膜超分辨光盘的读出机理符合孔径型超分辨读出模型。 相似文献