《照镜子》引导心得

镜子是我们生活中的必需品,大的、小的、方的、圆的,各种各样的镜子出现在我们的生活中。家里挂着的、镶嵌在衣柜里的,妈妈包里装着的,商场里立着的,甚至走在马路上,我们都可以看到一整栋楼的玻璃幕墙像镜子一样映照着我们的身影。每天孩子们看妈妈照着镜子打扮得漂漂亮亮去上班,自己也要过去照—照。

Deformation defects and electron irradiation effect in nanostructured Al-Mg alloy processed by severe plastic deformation

In order to explore the exact nature of deformation defects previously observed in nanostructured Al-Mg alloys subjected to severe plastic deformation, a more thorough examination of the radiation effect on the formation of the planar defects in the high pressure torsion （HPT） alloys was conducted using high-resolution transmission electron microscopy （HRTEM）. The results show that high density defects in the HRTEM images disappear completely when these images are exposed under the electron beam for some duration of time. At the same time, lattice defects are never observed within no-defect areas even when the beam-exposure increases to the degree that holes appear in the areas. Therefore, it is confirmed that the planar defects observed in the HPT alloys mainly result from the significant plastic deformation and are not due to the radiation effect during HRTEM observation.

幽默

班干部 儿子班里重选班干部．放学后他兴高采烈地回到了家。妈妈见了问：“这么高兴，一定是连续当选班干部了？”。

Irradiation Damage of Nano-C2S Particles Studied by In-Situ Transmission Electron Microscopy

Development of a reactive nanocement is a new approach to improve the physical and chemical properties of construction materials. However, due to the decreased size of cement particles, beam damage during transmission electron microscope （TEM） observation becomes more severe than in conventional cement. In this work, irradiation damage to nano-C2S （dicalcium silicate） is observed and studied by in-situ evolution of diffraction patterns （DP）, high resolution TEM （HRTEM）, and electron energy-loss spectroscopy （EELS）. The results show that the damage to nano-C2S occurs through a decomposition reaction. Nano-C2S is first amorphized, and then re-crystallized into CaO nano-crystals with average size of 7 nm surrounded by an amorphous matrix of Si and SiO2. During this process, C2S particles exhibit volume shrinkage. The damage energy causing the reaction was analyzed and electron-electron inelastic scattering produced radiolysis and heat, leading to the observed phenomena.

TEM Foil Preparation from Irradiated Metallic Materials： A Practical Approach

This paper focuses on work related to post irradiation examination of 300-series austenitic stainless steel taken from reactor vessel internals of PWR. High neutron irradiation dose in NNP＇s leads to a degradation of microstructure of the material in a nano-metric scale. Hence, it is important to characterize the irradiated materials to understand the physical basis of the degradation mechanisms. Microstructural characterization of neutron-irradiated materials by TEM requires enhanced sample preparation methodologies, which commonly needs general improvements regarding particular experiment to be performed. In this study, the authors have developed methodology specialized in 1 mm TEM thin foil preparation from a deformed shank of a broken miniaturized tensile specimen. TEM foil size in current studies is smaller than standard because of the small shank diameter and high radioactivity of the studied material. The reduction of the TEM foil radioactivity to minimum is crucial to perform EDX chemical analysis and to increase the EDX detector lifetime. This paper describes whole process from bulk sample handling, including remote-controlled material cutting in shielded hot-cells and disc polishing in glow-boxes, up to the final procedure of electrolytic-polishing of electron transparent 1 mm TEM foils. Eventually, results of TEM microanalysis of radiation-induced defects were present.

Photocatalytic Denitrogenation over Modified Waste FCC Catalyst

The strontium modified waste FCC catalyst was prepared by magnetic stirring method and characterized by Xray diffractometry(XRD),UV-Vis diffuse reflectance spectrometry(DRS),X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM).Meanwhile,its photocatalytic denitrogenation performance was evaluated in terms of its ability to degrade the N-containing simulation oil under visible light.A mixture of strontium nitrate solution(with a concentration of 0.5 mol/L)and waste FCC catalyst was calcined at 400℃for 5 h prior to taking part in the photocatalytic denitrogenation reaction.The test results showed that the photocatalytic degradation rate of pyridine contained in simulation oil in the presence of the strontium modified FCC catalyst could reach 92.0% under visible light irradiation for 2.5 h.

Biocidal Effect of Gamma Radiation on the Ecology of Filamentous Fungal Populations Associated with Stone Deterioration

This study focused on the identification of the filamentous fungi associated with soapstone samples exposed to outdoor conditions and the biocidal effect of gamma radiations on isolated fungal populations in Minas Gerais State in Brazil. Two soapstone blocks were placed outdoors under tropical environmental conditions for 12 months. A total of 9 filamentous fungal populations were identified on their surfaces, namely Acremomium （cf.） alternatum, Alternaria alternata, Aspergillusfumigatus, Calcarisporium （cf.） arbuscula, Cladosporium cladosporioides, Curvularia lunata, Epicoccum nigrum, Fusarium equiseti and Penicillium citrinum. The gamma radiation assay was then carried out as a test of biocidal action by exposing all fungal populations to the ionizing radiation. The results showed that only the C. cladosporioides species was resistant to this biocidal agent, since it was able to increase its population post exposure. Scanning electron microscopy images identified the microbial colonization on the soapstone blocks and the stone elementar composition was analyzed by energy dispersive X-ray spectrometry. After treatment, there was no structural and aesthetic alteration in the soapstone samples, and evidencing that gamma radiation can be used as a biocidal agent. However, the resistance of the black fungal population indicates caution in the choice of gamma irradiation as biocidal treatment.

Anelasticity of twinned CuO nanowires

The mechanical behavior of CuO nanowires （NWs） was investigated by in situ transmission electron microscopy. During compression, the NWs exhibited high bending capabilities associated with high mechanical stress. Interestingly, anelasticity was consistently observed after stress release. Further investigations indicate that the anelasticity is intrinsic to the CuO NWs, although electron- beam irradiation was proved capable of accelerating the shape recovery. A mechanism based on the cooperative motion of twin-associated atoms is proposed to account for this phenomenon. The results provide insight into the mechanical properties of CuO NWs, which are promising materials for nanoscale damping systems.

Microemulsion synthesis and photocatalytic activity of visible light-active BiVO_4 nanoparticles

A water-in-oil microemulsion made up of a cyclohexane/n-hexyl alcohol/Polyethylene glycol tertoctylphenyl/aqueous solution including Bi3+ and VO+3 ions yields the spherical BiVO4 precursors with the size from 5 to 300 nm. Well-crystallized monoclinic scheelite BiVO4 particles with nanometer or micrometer size are fabricated in control by heating microemulsion precursors under various temperatures. The corresponding nucleation and growth process of as-prepared samples has also been investigated via TEM,which demonstrates the detailed morphological evolution of nuclei inside the precursors. As-prepared BiVO4 photocatalysts exhibit enhanced photocatalytic activity under visible-light irradiation in comparison with the bulk BiVO4 prepared by solid-state reaction. The highest RB degrading efficiency of 98% in 180 min under visible-light irradiation is observed for the sample calcined at 600 °C.

Microstructures of the interlayer in Mo/Si multilayers induced by proton irradiation

In this work,the microstructure and optical properties of the Mo/Si multilayers mirror for the space extreme-ultraviolet solar telescope before and after 100 keV proton irradiation have been investigated.EUV/soft X-ray reflectometer(EXRR) results showed that,after proton irradiation,the reflectivity of the Mo/Si multilayer decreased from 12.20% to 8.34% and the center wavelength revealed red shift of 0.38 nm,as compared with those before proton irradiation.High-resolution transmission electron microscopy(HRTEM) observations revealed the presence of MoSi 2,Mo 3 Si and Mo 5 Si 3 in Mo-on-Si interlayers before irradiation.The preferred orientation such as MoSi 2 with(101) texture and Mo 5 Si 3 with(310) texture was formed in Mo-on-Si interlayers after proton irradiation,which led to the increase of thickness in the interlayers.It is suggested that the changes of microstructures in Mo/Si multilayers under proton irradiation could cause optical properties degradation.