The study of the secondary electron composition contrast imaging method have been developed with a conventional scanning electron microscope (SEM) equipped with ultra-thin window energy dispersive X-ray spectrometer (EDS). On the basis of the study of the principle of secondary electron emission, secondary electron composition contrast imaging method has been investigated, and the ranges of its application were also discussed. This method was applied in the microstructure studies on cathode materials of TWT (traveling wave tube). The results showed that, compared with backscattered electron image, the secondary electron image could also reveal composition contrast well in certain conditions. Furthermore, the resolution of secondary electron composition contrast image is higher. In some cases, the secondary electron image could distinguish impurities which might bring wrong results. In the microstructure studies on cathode materials of TWT, compared with backscattered electron image, secondary electron composition contrast imaging method is reasonable and practicable.
The well formed formulas (wffs) in classical formal system of propositional calculus (CPC) are only some formal symbols, whose meanings are given by an interpretation. A probabilistic logic system, based on a probabilistic space, is an event semantics for CPC, in which set operations are the semantic interpretations for connectives, event functions are the semantic interpretations for wffs, the event (set) inclusion is the semantic interpretation for tautological implication, and the event equality = is the semantic interpretation for tautological equivalence. CPC is applicable to probabilistic propositions completely. Event calculus instead of truth value (probability) calculus can be performed in CPC because there arent truth value functions (operators) to interpret all connectives correctly.
Now carbon steel is used in the engineering aspects and it is the oldest and the largest amount of basic materials. How to determine whether they are high-quality carbon steel? In this paper the standard data of high quality carbon steel by using the classical BP neural network algorithm is researched. Then it is simulated and predicted. The final comprehensive evaluation and analysis show that the neural network model can be used to decide whether it is a high quality carbon steel. Further, it has a good practical application value for utilizing high-quality carbon steel rationally.
In this article a model based on cellular automata (CA) is proposed to simulate the degradation for biodegradable polymer. The transformational rule of this model is constructed based on the hydrolysis reaction, oligomer diffusion equations and the relationship between intensity and number average molecular weight of the polymer. Furthermore, polymer DLPLA plate corresponding to this CA model was carried out. The simulation shows the middle hollow result which is accordance with the experiment phenomenon. The molecular in the degradation process has good fit with the experiment data. It proves that the model in this article is right and can provide numerical lead for the designs of biodegradable polymer devices.
Although the degradation modeling of tissue engineering scaffold is in its initial step, it can direct the design, optimization of scaffold and help the application in medical case of illness. This paper analyzes the modeling methods and gives the speciality of every model which is put forward by researchers in China and abroad about the degradation of tissue engineering scaffold. These models are divided into micro scale, macro scale and two scale models based on the modeling scales. The recent research is belonging to single scale modeling. Some researchers abroad probed to two scale modeling. The future model is prospected in multi scale coupling macro, micro, and meta-macro model.
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