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Short Communication—A Novel Sample Preparation Method That Enables Ultrathin sectioning of Urea-Formaldehyde Resin for Imaging by Transmission Electron Microscopy

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Microscopy Research 2013年第1期1卷 1-6页

作者： Adya P. Singh Arif Nuryawan Byung- Dae Park Department of Wood Science and Technology Kyungpook National University Daegu South Korea.

Urea-formaldehyde (UF) resin is widely used as an adhesive for the manufacture of a range of wood and fiber based products. Although the microstructure of this resin has been examined at high resolution by field-emission scanning electron microscopy and atomic force microscopy, transmission electron microscopy (TEM) has thus far not been used, perhaps because of difficulties in ultrathin sectioning this resin in cured (polymerized) state. In the technical note presented here, a novel sample preparation method is described which enabled us to examine the microstructural morphology of UF resin by transmission electron microscopy in ultrathin sections, revealing the presence of spherical particles within the resin. Our initial attempt to ultrathin section the resin directly was not successful as it was too brittle to trim blocks for sectioning. Then, we developed a sample preparation technique that involved impregnation ofPinus radiatawood tissues with the UF resin, and then embedding of resin impregnated wood tissues with Spurr’s low viscosity embedding medium, which has been widely employed in plant and wood ultrastructure work. The TEM images illustrated and the information on the microstructural morphology of the UF resin presented are based on this novel sample preparation approach.

关键词： Urea-Formaldehyde (UF) Resin Ultrathin sectioning Transmission Electron Microscopy Pinus radiata Veneer Microstructure Spherical Particles

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Topology characteristics of three-dimensional grains in polycrystalline materials

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Science China(Technological Sciences) 2019年第2期62卷 263-268页

作者： WANG Hao XUE WeiHua KANG RenMu ZHANG YiFan LIU GuoQuan School of Materials Science and Engineering University of Science and Technology Beijing School of Materials Science and Engineering Liaoning Technical University Deyang Products Quality Supervision and Inspection Institute Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing

The quantitative microstructural analysis in recrystallized pure iron is carried out by serial sectioning experiment coupled with three-dimensional(3-D) grain reconstruction technique. The full 3-D morphology of 16254 pure iron grains, which is the largest experimental 3-D grain dataset to date, is obtained. It is shown that the peak and the mean of the grain face number distribution were 10 and 13.5, respectively. For individual grains, the average trends that the highest and lowest face classes exhibited the highest affinity for mutual contact but the lowest affinity for contact with themselves are experimentally confirmed by 3-D pure iron grains. The pure iron grains are observed to have much more three-edged faces than Monte Carlo grains, resulting in relatively higher average dispersions of the grain edge distribution.

关键词： 3-D characterization serial sectioning Monte Carlo grain growth topology

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Porosity Effects on Interlaminar Fracture Behavior in Carbon Fiber-Reinforced Polymer Composites

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Materials Sciences and Applications 2017年第2期8卷 170-187页

作者： Issa A. Hakim Steven L. Donaldson Norbert G. Meyendorf Charles E. Browning Department of Mechanical & Aerospace Engineering University of Dayton Dayton OH USA Fraunhofer-IKTS Berlin Germany Department of Mechanical Engineering Omar Al-Mukhtar University El-Beida Libya Department of Civil & Environment Engineering & Engineering Mechanics University of Dayton Dayton OH USA Department of Aerospace Engineering Iowa State University Ames IA USA Department of Chemical & Materials Engineering University of Dayton Dayton OH USA

Fiber-reinforced polymer composite materials have become materials of choice for manufacturing application due to their high specific stiffness, strength and fatigue life, low density and thermal expansion coefficient. However, there are some types of defects such as porosity that form during the manufacturing processes of composites and alter their mechanical behavior and material properties. In his study, hand lay-up was conducted to fabricate samples of carbon fiber-reinforced polymer composites with three different vacuum levels in order to vary porosity content. Nondestructive evaluation, destructive techniques and mechanical testing were conducted. Nondestructive evaluation results showed the trend in percentages of porosity through-thickness. Serial sectioning images revealed significant details about the composite’s internal structure such as the volume, morphology and distribution of porosity. Mechanical testing results showed that porosity led to a decrease in both Mode I static interlaminar fracture toughness and Mode I cyclic strain energy release rate fatigue life. The fractographic micrographs showed that porosity content increased as the vacuum decreased, and it drew a relationship between fracture mechanisms and mechanical properties of the composite under different modes of loading as a result of the porosity effects. Finally, in order to accurately quantify porosity percentages included in the samples of different vacuum levels, a comparison was made between the parameters and percentages resulted from the nondestructive evaluation and mechanical testing and the features resulted from fractography and serial sectioning.

关键词： Carbon Fiber Reinforced Composite Nondestructive Evaluation Porosity Fatigue Fracture Behavior Serial sectioning

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Preliminary Study on the Histology in the Head Sarcoma of Goldfish (Carassius auratus)

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Open Journal of Animal Sciences 2015年第1期5卷 44-49页

作者： Lei Wang Zaizhong Chen Caixia Hu Feng Yan Jun Xu Xuehua Wang Yuanyuan Zhou Wei Wang Weihua Zhao College of Fisheries and Life Sciences Shanghai Ocean University Shanghai China Shanghai Pudong Ornamental Fish Center Shanghai China

The sarcoma structure of goldfish was first analyzed by frozen section technique. The present study revealed the alkaline and acid phosphatase distribution in the head sarcoma of goldfish. And the histochemical staining in situ by calcium-cobalt method and lead nitrate method displayed a large amount of alkaline and acid phosphatases in the head sarcoma, with higher enzyme activity. The alkaline and acid phosphatases belong to hydrolases, which are widely present in various tissues. The results showed that the activity of external sarcoma is similar to the middle one, while there was more alkaline phosphatase near to the tissue sarcoma under the goldfish scales. And they have the strong activity. The study will lay the theoretical basis on enhancing the ornamental value of goldfish.

关键词： Goldfish Head Sarcoma Frozen sectioning Method AKP ACP

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