Graphite Oxide and Aromatic Amines: Size Matters

Experimental and theoretical studies are performed in order to illuminate, for first time, the intercalation mechanism of polycyclic aromatic molecules into graphite oxide. Two representative molecules of this family, aniline and naphthalene amine are investigated. After intercalation, aniline molecules prefer to covalently connect to the graphene oxide matrix via chemical grafting, while napthalene amine molecules bind with the graphene oxide surface through π–π interactions. The presence of intercalated aromatic molecules between the graphene oxide layers is demonstrated by X‐ray diffraction, while the type of interaction between graphene oxide and polycyclic organic molecules is elucidated by X‐ray photoelectron spectroscopy. Combined quantum mechanical and molecular mechanical calculations describe the intercalation mechanism and the aniline grafting, rationalizing the experimental data. The present work opens new perspectives for the interaction of various aromatic molecules with graphite oxide and the so‐called “intercalation chemistry”.     

X射线干涉光刻光束线关键光学元件热-结构耦合分析

为了保证上海光源X射线干涉光刻光束线的稳定性,减小热变形对实验结果的影响,对X射线干涉光刻光束线的3个关键光学元件——偏转镜、聚焦镜和精密四刀狭缝进行热-结构耦合分析。首先,计算偏转镜、聚焦镜和精密四刀狭缝所承载的功率密度;然后,建立其有限元模型;最后,获得光学元件的温度场和热变形的结果。结果表明,偏转镜和聚焦镜采用间接水冷方式可有效抑制热变形,冷却后的最大面形误差分别为7.2μrad和9.2μrad。精密四刀狭缝未冷却时,刀片组件温度介于271.56~273.27℃,刀口热变形为0.19 mm,直线导轨热变形为0.08 mm;经过铜辫子冷却后,刀片组件温度降至22.24~23.94℃,刀口热变形降至0.2μm,直线导轨热变形降至0.1μm;采用影像法和接触探头法测试后,刀口直线度、平行度和重复精度均满足技术要求。偏转镜、聚焦镜和精密四刀狭缝的热变形通过间接水冷和铜辫子的冷却方式可以得到很大程度的抑制,进而保证光斑质量。     

Electrical Breakdown Properties and Space Charge Formation in High Temperature Region in Ultraviolet Ray Irradiated PVC

Polyvinyl chloride (PVC) is the most popular insulating material for electric wiring instruments. However, an exothermic reaction above 150 °C may cause deterioration of the insulating properties of PVC. Therefore, it is important to clarify the heat degradation in PVC, not only to investigate the ignition of electrical wiring products but also to use electrical products safely. It is known that ultraviolet (UV) irradiation causes chemical deterioration of PVC and an increase in its conductivity. Generally, it has been thought that the electrical breakdown properties, electrical conduction, and insulating performance are affected by space charge accumulation in an insulating material. A high temperature pulsed electroacoustic (PEA) system usable up to 250 °C has been developed, and the PEA system can measure the space charge distribution and conduction current in the high temperature range simultaneously. In this investigation, the space charge distribution and conduction current were measured up to electrical breakdown in a non‐UV irradiated sample (normal PVC) and in 353 nm and 253 nm UV‐irradiated PVC samples in the range from room temperature to 200 °C in a DC electric field. In the short wavelength UV irradiated PVC sample (253 nm, 300 h), a deterioration of breakdown strength at 90 °C to 150 °C and negative packet‐like charges were observed at 60 °C and 100 °C, a positive charge accumulated in front of both the anode and cathode above 90 °C, and a higher electric field near the cathode side because the positive charge of the cathode side was greater.     

Matrix influence on the piezoelectric properties of piezoelectric ceramic/polymer composite exhibiting particle alignment

This study was addressed to the influence of an electric field strength applied at fabrication process and matrix properties, such as the dielectric constant and the Young's modulus, on “pseudo‐1‐3 piezoelectric ceramic/polymer composite” in order to further enhance the piezoelectricity of that. The pseudo‐1‐3 piezoelectric ceramic/polymer composite consists of linearly ordered piezoelectric ceramic particles in polymer material. Silicone gel, silicone rubber, urethane rubber, and poly‐methyl‐methacrylate, which exhibit different dielectric constants and Young's modulus, were used as matrices to evaluate the matrix influence. The piezoelectricity of the pseudo‐1‐3 piezoelectric ceramic/polymer composite was evaluated using the piezoelectric strain constant d₃₃. The d₃₃ is one of the indices of the piezoelectric properties for piezoelectric materials. As a result, it was confirmed that d₃₃ of the pseudo‐1‐3 piezoelectric ceramic/polymer composite increased with the increase of the electric filed strength applied at fabrication process, though, it reached a constant value at a certain strength value. Further it was confirmed that dielectric constant of the matrix had a small influence on d₃₃ of the pseudo‐1‐3 piezoelectric ceramic/polymer composite, however, in case of matrix of lower Young's modulus, d₃₃ was increase. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41817.     

三维最短路径法射线追踪及改进

射线追踪技术在地震学领域有着广泛的应用，其中以最短路径算法在复杂介质中走时计算稳定性最好。理论上最短路径法的误差来源为速度模型采样误差、空间离散化误差和角度离散化的误差，由此造成网格稀疏时射线路径呈之字形，计算走时比实际走时偏大。弯曲法追踪精度高，但是射线追踪速度受初始路径与真实射线路径逼近程度制约，在复杂介质中可能找不到全局最小走时路径。最短路径法追踪出来的网格射线路径，可以作为较理想的初始路径，供弯曲法迭代优化。将最短路径法和弯曲法结合，通过射线在初始路径附近的扰动得到Fermat原理约束下的最短路径。文章对常速模型的试算，显示了改进方法对射线路径优化的作用，在模型网格稀疏的情况下效果尤其明显。本算法适用于计算三维任意复杂介质中初至波走时和射线路径，可应用于三维走时层析成像等领域。     

Oxidation of doped europium in BaMgAl10O17 by annealing studied by x‐ray‐absorption fine‐structure measurements

Abstract— We studied the influence of annealing in air on doped europium in BaMgAl₁₀O₁₇ by performing x‐ray absorption fine‐structure measurements. We determined the oxidation of doped divalent europium by annealing in air at over 500°C. The interatomic distance between the europium and the surrounding oxygen atoms was compressed by oxidation. It also appears that the oxidation process of europium is determined by the diffusion of oxygen into BaMgAl₁₀O₁₇.     

DGPSL：A DISTRIBUTED GRAPHICS LIBRARY

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磷钨酸乙醇染色法在嗜铬颗粒电镜X射线显微分析中的应用

通过比较常规透射电镜制样法、快速冷冻固定－冷冻超薄切片法及磷钨酸乙醇（EPTA）染色法在嗜铬颗粒透射电镜X射线显微分析中的应用，发现磷钨酸乙醇染色法能使嗜铬颗粒电子着色，从而较好地显示嗜铬颗粒的超微结构。同时磷钨酸乙醇染色法也以在一定程度上原位保留生物样品中元素，可以应用于检测样品元素含量的变化或比较样品元素含量的组间差别，提示磷钨酸乙醇染色法是一种可应用于透射电镜X射线显微分析的经济简便的生物样品制备方法。     

Si1-xGex/Si应变材料的生长及热稳定性研究

利用分子束外延（MBE）技术生长了Ge组份为0.1-0.46的Si1-xGex外延层。X射线衍射线测试表明，SiGe/Si异质结材料具有良好的结晶质量和陡峭界面，其它参数与可准确控制。通过X射线双晶衍射摆曲线方法，研究了经700℃、800℃和900℃退火后应变SiGe/Si异质结材料的热稳定性。结果表明，随着退火温度的提高，应变层垂直应变逐渐减小，并发生了应变弛豫，导致晶体质量退化；且Ge组分越小，Si1-xGex应变结构的热稳定性越好；室温下长时间存放的应变材料性能稳定。     

Photoluminescence and X-ray Diffraction of Distributed Bragg Reflector

Spectral and structural characteristics of distributed Bragg reflector (DBR) in vertical-cavity surface-emitting lasers were studied with photoluminescence and double- crystal X- ray diffraction measurement. The expected high quality epitaxial DBR structure was verified. In the X- ray double- crystal rocking curves of DBR the zeroth- order peak, the first and second order satellite peaks were measured. Splitting of diffraction peak appeared in the rocking curves was analyzed. The effects of introduced deep energy levels on the structural perfection and optical properties were discussed.