膜系光谱系数对膜层参数的一阶和二阶偏导数的计算模型

为了寻找一种膜系深入分析与设计的有力辅助计算工具,从光学薄膜光谱系数的矩阵计算理论出发,基于对矩阵求迹运算的巧妙运用,从数学上建立了准确计算膜系光谱系数关于膜层几何厚度、实际折射率和消光系数等膜层参数的一阶和二阶偏导数的解析模型。这一偏导数计算模型物理上与矩阵理论具有一致的通用性和普适性,适用于任何各向同性的均匀膜系统。在数学上也严格成立,数值编程计算不存在差分近似,精度达到了计算机浮点运算的极限精度。而且算法运算费时少,计算速度快,取得了高度准确性和便于实时化的双重优越性能,非常有利于应用于膜系设计领域来提高膜层数较大时的设计速度和效率。同时,这一模型能非常便捷和准确地给出膜系许多实用的导数信息,对膜系分析、测量和膜厚监控等领域中的相关应用具有重要的参考意义。     

脉冲激光频域干涉技术在超快动力学物理中的应用

介绍了一种具有fs时间分辨力的超短脉冲激光频域干涉测试技术,详细论述了该技术的工作原理和系统构成,指出传输时间差和相位差是影响频域干涉条纹周期的主要因素。采用脉冲激光频域干涉仪测量了200 nm厚度铝膜在波长800 nm、单脉冲能量0.7 mJ、脉宽35 fs脉冲激光作用下的运动速度剖面。在单次飞秒脉冲激光作用下,铝膜自由面的运动速度峰值可达960 m/s,速度剖面的上升前沿小于5.77 ps,表明脉冲激光频域干涉技术可用于测量材料在超快脉冲激光作用下的冲击动力学参数。     

A comparison of silicon oxide and nitride as host matrices on the photoluminescence from Er+ ions

This paper compares the properties of silicon oxide and nitride as host matrices for Er ions.Erbium-doped silicon nitride films were deposited by a plasma-enhanced chemical-vapour deposition system.After deposition,the films were implanted with Er3+ at different doses.Er-doped thermal grown silicon oxide films were prepared at the same time as references.Photoluminescence features of Er3+ were inspected systematically.It is found that silicon nitride films are suitable for high concentration doping and the thermal quenching effect is not severe.However,a very high annealing temperature up to 1200° C is needed to optically activate Er3+,which may be the main obstacle to impede the application of Er-doped silicon nitride.     

High-lying excited states in <Superscript>10</Superscript>Be from the <Superscript>9</Superscript>Be(<Superscript>9</Superscript>Be,<Superscript>10</Superscript>Be)<Superscript>8</Superscript>Be reaction

A transfer-reaction experiment of ⁹Be(⁹Be, ¹⁰Be)⁸Be was performed at a beam energy of 45 MeV. Excited states in ¹⁰Be up to 18.80 MeV are produced using missing mass and invariant mass methods. Most of the observed high-lying resonant states, reconstructed from the α + ⁶He and t + ⁷Li decay channels, agree with the previously reported results. In addition, two new resonances at 15.6 and 18.8 MeV are identified from the present measurement. The 18.55 MeV state is found to decay into both the t + ⁷Li_g.s. and t + ⁷Li* (0.478 MeV) channels, with a relative branching ratio of 0.93 ± 0.33. Further theoretical investigations are encouraged to interpret this new information on cluster structure in neutron-rich light nuclei.     

Effect of defect configuration on the localization of phonons in two-dimensional phononic crystals

Effects of defect location on the defect frequency and the localization of phonons are investigated in two novel kinds of model, created by moving the location of the native cylinder and inserting an ad-cylinder in the central cellular respectively. The results show that the defect frequency in Model 1 is only related to the distance, while in Model 2, is related not only to the distance, but also to the moving direction. From the pressure distribution, obvious localization phenomenon is found. The position and shape of the localized energy are varied with the position of the defect.     

Evaluation of ADC measurements among solid pancreatic masses by respiratory-triggered diffusion-weighted MR imaging with inversion-recovery fat-suppression technique at 3.0 T

Purpose

The objective of this paper was to investigate the value of apparent diffusion coefficients (ADCs) for differential diagnosis among solid pancreatic masses using respiratory triggered diffusion-weighted MR imaging with inversion-recovery fat-suppression technique (RT-IR-DWI) at 3.0 T.

Materials and Methods

20 normal volunteers and 72 patients (Pancreatic ductal adenocarcinoma [PDCA, n = 30], mass-forming pancreatitis [MFP, n = 15], solid pseudopapillary neoplasm [SPN, n = 12], and pancreatic neuroendocrine tumor[PNET, n = 15]) underwent RT-IR-DWI (b values: 0 and 600 s/mm²) at 3.0 T. Results were correlated with histopathologic data and follow-up imaging. ADC values among different types of pancreatic tissue were statistically analyzed and compared.

Results

Statistical difference was noticed in ADC values among normal pancreas, MFP, PDCA, SPN and PNET by ANOVA (p < .001). Normal pancreas had the highest ADC value, then followed by PNET, PDCA, MFP and SPN. There was noticeable statistical difference in ADC values among PDCA, MFP and normal pancreas by Least Significant Difference (LSD) (p < .001). ADC of SPN was statistically lower than that of PNET (p = 0.1800 × 10^− 4), PDCA (p = 0.0300 × 10^− 4) and normal pancreas (p = 0.0007 × 10^− 4). ADC of PNET was statistically lower than that of normal pancreas (p = 0.0360) and higher than that of MFP (p = 9.3000 × 10^− 4).

Conclusions

ADC measurements using RT-IR-DWI at 3.0 T may aid to disclose the histopathological pattern of normal pancreas and solid pancreatic masses, which may be helpful in characterizing solid pancreatic lesions.     

Optimization of direct modulation rate for circular microlasers by adjusting mode Q factor

Semiconductor microcircular lasers have been investigated as potential light sources for photonic integrated circuits and optical interconnections for more than two decades. However, the direct modulation bandwidths of the circular microlasers remain a challenge, especially when being compared with other microlasers, such as photonic crystal lasers. In this paper, microcircular lasers connected to an output waveguide are investigated for high‐speed direct modulation with optimized mode Q factors. Small signal modulation with a resonance frequency of f_R = 12.5 GHz is realized for a AlGaInAs/InP circular microlaser with a radius of 10 µm at 290 K. Furthermore, clear eye diagrams are observed at 12.5 Gbit/s for a 15‐µm radius circular microlaser with f_R = 6.9 GHz.     

生地当归药队煎剂的表面增强拉曼散射光谱

为揭示单味煎剂与方剂间的关系,分别测试分析了生地当归药队、单味药生地和单味药当归煎剂的表面增强拉曼散射(surface-enhanced Raman scattering, SERS)光谱,并对其进行谱峰归属。本文主要针对存在于三种煎剂中的17个拉曼信号(538,622,732,761,835,876,959,1 145,1 245,1 276,1 326,1 402, 1 456,1 470,1 518,1 546和1 605 cm-1)进行讨论。生地当归药队煎剂SERS光谱在538,732,761,835,876,959,1 145,1 245,1 276,1 326,1 402,1 456,1 470,1 518和1 605 cm-1处,出现15个明显的拉曼信号;生地煎剂SERS光谱在538,761,835,876,959,1 145,1 245,1 276,1 326,1 402,1 470,1 518和1 546 cm-1处,出现13个明显的拉曼信号;当归煎剂SERS光谱在538,622,732,761,835,876,959,1 245,1 326和1 402 cm-1处,出现10个明显的拉曼信号。生地当归药队煎剂SERS光谱保留了和未观察到生地和当归单味煎剂的某些拉曼峰,且产生了生地和当归单味煎剂中所没有的拉曼信号(1 456和1 605 cm-1),即产生新药物成分。生地当归药队煎剂所包含的药物成分并非是生地和当归单味药物煎剂所含药物成分的简单相加。结果表明,SERS光谱可能为方剂研究提供一种高灵敏度、快速准确和操作简单的检测方法。     

Asymptotic Behavior of Least Energy Solutions for a Fractional Laplacian Eigenvalue Problem on ℝN

Acta Mathematica Sinica, English Series - We are interested in the existence and asymptotic behavior for the least energy solutions of the following fractional eigenvalue problem $$left({rm{P}}...     

Ni_n(n=2～20)团簇的结构

使用经验势和遗传算法 (GeneticAlgorithm) ,得到了Nin(n =2～ 2 0 )团簇的平衡结构和束缚能。对于小的团簇 (Ni2 ～Ni6) ,所得到的结果与基于第一性原理密度泛函的计算相一致。结果表明 ,团簇的结构不同于块体且随尺度发生引人注日的变化。每原子平均束缚能Eb 随尺度单调增长。根据过渡金属团簇表面原子配位数与电离势 (IP)的一个解析表达式计算所得的电离势与实验结果基本一致。由基态能量对分裂途径(FragmentationChannels)的分析表明 ,失去二聚体 (Dimer)在能量上是优先的。同时将计算所得的结构与Nin团簇吸收N2 的实验所推得的结构进行了比较