Photo-induced evolution of copper sheets from cluster molecules and its application to photolithographic copper patterning

UV photoexcitation of (t-butylethynyl copper)₂₄ cluster films induces segregation of the crystals into metallic and organic phases and leads to evolve the metallic sheets sandwiched by organic polymers. The growth of the metallic crystals in the plane of the photo-electromagnetic field is attributed due to plasmon-plasmon interaction among nanoparticles embedded in dielectric polymer matrices. The surface enhanced photochemical reaction of residual cluster molecules on the photon incident direction is expected to take an important role for joining the metal particles to produce a metallic sheet. We can apply this phenomenon for photolithographic copper pattern generation on a flexible base plate.     

Chemical Reactivity of Tetrasulfur Tetranitride: Synthesis,Physical Properties,and Structural Characterization of the Amorphous Phase Cu7S4N4

Tetrasulfur tetranitride, S₄N₄, reacts with elemental Cu within inert solvents to a black‐blue material of approximate composition Cu₇S₄N₄ which is totally amorphous to X‐rays and which cannot be made crystalline by either thermal treatment or electron radiation. Cu₇S₄N₄ explodes if heated above 234 °C or when subjected to mechanical shock to eventually yield copper(I) sulfide; this together with the characteristic infrared spectrum of Cu₇S₄N₄ indicates the presence of molecular S₄N₄ units inside the amorphous phase. The metastable nature of Cu₇S₄N₄ is also mirrored by electron microscopy which furthermore allows the structural characterization of its degradation products. Based on experimental EXAFS data offering characteristic Cu—N and Cu—S distances, a theoretical crystalline approximant of Cu₇S₄N₄ was suggested and structurally optimized by density‐functional total‐energy calculations including periodic boundary conditions. This model incorporates a central S₄N₄ unit bonded to three shells of Cu atoms of different functionalities; in addition, a partial rupture of the S₄N₄ unit is likely to allow for a lowering of the total energy of the metastable phase. The latter observation supports the impossibility to make Cu₇S₄N₄ crystallize using ₄N₄ crystallize using whatever kind of measures.     

球形钴酸锂的乳液法合成及其结构、性能研究

采用一种特殊乳液法, 制备了锂离子电池正极材料球形LiCoO₂. 分别研究了一次颗粒尺寸、烧结时间对于二次造粒的影响. 还对LiCoO₂球体内部的结构进行了SEM和HRTEM研究, 发现一次颗粒非常紧密地融合在一起, 晶体边界区域没有明显的非晶相区, 也没有纳米级别的孔洞、裂缝. 电化学性能研究表明, 在900 ℃烧结4 h的材料具有较高的首次放电容量(143 mAh•g^－1)和良好的循环性能     

Formation of supported size-controlled nanoparticles of sulfated zirconia

Methods of the preparation of catalysts for alkane skeletal isomerization based on uniform nanoparticles of sulfated zirconia anchored to different supports were investigated. These catalysts were characterized by using the ICP, HRTEM and BET techniques. The activities of the catalysts in the reaction of n-butane isomerization were measured and compared with those of bulk catalysts.     

无烟煤结构的高分辨电镜研究

镜质组不仅是煤结构变化最具规律性，也是影响煤质的主要微成分。用点分辨率为２．１Ａ的高分辨电镜对几种不同煤化程度的无烟煤大分子结构进行了研究。结果表明：电镜图像直接表征了无烟煤分子的非均匀性孔隙结构。京西煤分子方向化程度强，主要以芳层平行堆或有序化前结构为主；晋城煤方向化程度弱，主要以粒状嵌晶结构为主。高分辨电镜技术是研究煤分子结构和煤化作用实质的有效方法。     

Synthesis and characterization of n=5, 6 members of the La4Srn−4TinO3n+2 series with layered structure based upon perovskite

Layered compounds have been synthesized and structurally characterized for the n=5 and 6 members of the perovskite-related family La₄Sr_n−4Ti_nO_3n+2 by combining X-ray diffraction and transmission electron microscopy. Their structure can be regarded as comprising [(La,Sr)₅Ti₅O₁₇] and [(La,Sr)₆Ti₆O₂₀] perovskite blocks joined by crystallographic shears along the a-axis, with consecutive blocks shifted by 1/2 [100]_p. The n=5 member is similar to the previously reported n=5 member of other A_nB_nO_3n+2-related series. The n=6 member, which has only been briefly reported in other systems previously, is also a well-behaved member of this A_nB_nO_3n+2 series.     

Analysis of polished polycrystalline diamond using dual beam focused ion beam microscopy

This paper presents a study on polycrystalline diamond (PCD) polished by dynamic friction polishing (DFP) with the aid of advanced dual beam FIB (focused ion beam) microscopy. After disclosing a variety of wear tracks by DFP using electron imaging in combination with the ion channelling effect, a dual beam FIB was successfully employed at wear track sites to specifically create both the large cross-sectional specimen for microanalysis and thin foil for nanoanalysis. The study concluded that the polished PCD subsurface was free from microscale cracking. However, the attached debris layer on the top surface contained metal oxides and non-diamond carbon phase with inhomogeneous distributions of C, Fe, Cr, Ni, Si and O across the layer. An attached layer directly above a diamond grain was composed of essentially amorphous carbon, suggesting that a direct phase transformation from diamond crystalline to amorphous occurred during DFP.     

Microstructure and Magnetic Properties of Carbon‐Coated Nanoparticles

Abstract

In the present work, microstructure and superparamagnetic properties of two types of carbon‐coated magnetic Ni and Fe nanoparticles [Ni(C) and Fe(C)] are reviewed. High‐resolution transmission electron microscopy (HRTEM), electron diffraction (SAED), and x‐ray diffraction (XRD) analyses have been used to reveal the distinct structural morphologies of Ni and Fe nanoparticles. Moreover, novel carbon‐coated Ni nanoparticle assemblies offer us great opportunities for studying the mechanism of superparamagnetism in particle assemblies. Magnetization measurements [M(T) and M(H) curves] for assemblies of Ni nanoparticles indicate that modified superparamagnetic properties at T > T _B, have been found in the assemblies of Ni(C) particles. The blocking temperature, T _B, is determined to be near 115K under a certain applied field. Above T _B, the magnetization M(H, T) can be described by the classical Langevin function L using the relation, M/M _s (T = 0) = coth (μH/kT) ? kT/μH. It is suggested that these assemblies of carbon‐coated Ni nanoparticles have typical single‐domain, field‐dependent superparamagnetic relaxation properties. Finally, Mössbauer spectra and hyperfine magnetic fields at room temperature for the assemblies of Fe(C) nanoparticles confirm their distinct nanophases that were detected by structural analysis. Modified superparamagnetic relaxation is observed in the assemblies of Fe(C) nanoparticles, which is attributed to the nanocrystalline nature of the carbon‐coated nanoparticles.     

Microstructures and soft magnetic properties of Fe80P20-xSix (x = 4.5–6.5) amorphous ribbons

Fe-based amorphous ribbons with excellent soft magnetic properties and mechanical properties were prepared in the Fe–Si–P ternary system. Enhanced soft magnetic properties could be achieved through annealing treatment of the ribbons for 1 h at 325 °C, which is far below the glass transition temperatures (462–474 °C). Icosahedral medium-range ordering with a size range of around 2 nm occurred throughout the amorphous matrix during the low-temperature annealing treatment. The annealed ribbons exhibited improved magnetic saturation of over 185 emu/g while maintaining good mechanical flexibility. During icosahedral ordering, the distance between the Fe atoms and the coordination number within the amorphous ribbon can be optimised for achieving high magnetic saturation. However, nanocrystallisation of the SiP and Fe₂P transition phases embedded within the amorphous matrix occurred after the annealing treatment for 1 h at 385 °C, which caused deterioration of the soft magnetic properties and mechanical flexibility of the ribbons. Therefore, the combination of high magnetic saturation and mechanical flexibility of the amorphous ribbons could be optimised through low-temperature annealing treatment without any nanocrystallisation.     

Cross‐sectional structural characterization of the surface of exfoliated HOPG using HRTEM‐EELS

We analyzed the surface atomic structure of highly oriented pyrolytic graphite (HOPG) substrate exfoliated with adhesive tape, using high‐resolution transmission electron microscopy and scanning transmission electron microscopy‐electron energy‐loss spectroscopy (STEM‐EELS). The surface step height of the exfoliated HOPG substrate was determined using high‐angle annular dark‐field‐scanning transmission electron microscopy (HAADF‐STEM) images and the depth profiles of the EELS spectra of a cross‐sectioned thin foil specimen prepared via focused ion beam milling. The exfoliated surface of the HOPG substrate presented disordered and curved graphene layers. The STEM‐EELS measurements indicated that upon exfoliation, the surface of the HOPG substrate reacted with atmospheric water and oxygen molecules.