Papers by Keyword: Computer Simulation

Abstract: Mechanical properties of nanolayered materials were simulated using molecular dynamics method. Elastic modulus was especially focused in this study, and the effect of layer width and the interval of the layers on the deformation behavior were discussed. Tension was imposed by adding a mono-axial strain in the x direction at a constant rate, while the other two normal components of stress were controlled to be zero. The influence of the dimension was preliminarily checked to avoid the model-size dependency, and the suitable size was determined as a cube with 12 unit cells in the x, y and z directions. First, a single nanolayer was set in the model, and the layer width was varied. The obtained elastic modulus showed almost linear dependency with the layer width. Then the interval of the layer was varied, and it revealed that the elastic moduli depend on the cross-sectional ratio of the layered material rather than the layer interval.

Abstract: The research target is offset press, using computer simulation to analysis ink press system and the dynamic transfer process of ink, including the calculation of computer ink press system and solving ink thickness changes of the substrates ink film, and then to evaluate the characteristics and quality of inking system, and to guide the selection or design of inking system according to the research.

Abstract: The structural and elastic properties of the cubic spinel Ge₃N₄ semiconductor have been investigated using the ab initio scheme within the generalized gradient approximation in the framework of density functional theory. Quantities such as lattice constants and elastic constants of interest are calculated. A good agreement is found between our results and the other data. Through the lattice dynamics, in which the finite displacement method is used, we have obtained successfully the thermal properties such as the phonon curve, free energy, heat capacity and Debye temperature in the whole temperature range from 0 to 1000K. It is the authors ambition that these results will inspire further experimental study on the Ge-based semiconductors. * Corresponding author: CHEN Dong

Abstract: Ab initio electronic structures for β-Ge₃N₄ are investigated using ultrasoft pseudo-potential method within the generalized gradient approximation functional. The lattice parameters are predicted theoretically, and are compared with available experimental data and the other theoretical results. The elastic constants calculations reveal that the phenacite structure is a stable phase in the pressure range of 020GPa. The high bulk modulus (B=180.2GPa) indicates that β-Ge₃N₄ is a relatively hard material. β-Ge₃N₄ has a direct band gap of 2.94eV, indicating its promising applications as a semiconductor in electronics and optical fibers. On the other hand, the density of states analysis is also included in this paper.* Corresponding author: CHEN Dong

Abstract: The steel residential building has been widely used for its good seismic performances. In order to study the energy-saving behavior of the existing steel residential building, an on-site test on envelope structure of a typical steel building in cold region is conducted. Based on that, a simplified numerical model is established in which dynamic energy theories, solar radiations and indoor thermal disturbances are considered. The model is verified through testing data. Parameter analyses including 6 series sum up to 38 models are carried out on 6 main influential factors. The results show that improving thermal behavior of building envelope, adopting flexible sunshade schemes in different seasons, using even and simple building configuration and adopting different window-wall ratios for windows with different orientation are effective ways to decrease the energy consumption of buildings. The thermal design recommendations for steel residential buildings are also produced.

Abstract: This study evaluates the daylighting performance of a polycarbonate as a substitute for glass on top-lit buildings. For the study, the polycarbonate types and properties are analyzed and simulation tests are performed based on DF(daylight factor, %). As results, 16mm flat-plated, saw-blade and the diamond-type polycarbonate window are recommended as substitutes for window glasses. Also, when developing the polycarbonate as the top-lit buildings, it is advisable to apply the saw-blade and diamond-types to establish the direction of development.

Abstract: The author adopts Monte Carlo compute method to simulate the linear polymer chain lattice model in multiple chain systems of chain length n=20, 50, 100 while the volume fraction Φ=0.125, and makes a research on the variational situation of the size (measured with the mean-square end-to-end distance 2> and the mean-square radius of gyration 2>), shape (measured with the mean asphericity factor ) with changing of the interaction energy between solvent molecule and polymer chain segment molecule ε_PS. Results indicate 2>, 2> and have the changing rules that they become small with the increase of the ε_PS

Abstract: In order to stimulate growth model of poplar and achieve the visualization of poplar growth, the growth model is investigated from the perspective of computer simulation technology. The paper first presents physiological changes of poplar, discusses the changing rules of the space-time state of poplar growth, proposes the growth model of poplar based on state machine and predicts the growth of poplar authentically. Based on this model, the visualization algorithm of poplar growth is constructed; the data of poplar growth is properly organized; a simulation prototype system is developed to verify the validity of the model. Practice has shown that this growth model can simulate growth process of poplar and has high correctness and efficiency in the application of poplar visualization.

Abstract: Mastermind is code-breaking board game whose principle is to find as fast as possible the guess pattern of code pegs in color and position based on feedback realized by key pegs. The game is targeted at development of logical thinking. The process of the decoding can be realized also using computer. Mathematical analysis, strategy solution, algorithm development of solution and computer simulation program in MS Excel of decoding of the position order of already found and disordered colored pegs are shown in the paper.

Abstract: Mastermind is code-breaking board game whose principle is to find as fast as possible the guess pattern of code pegs in color and position based on feedback realized by key pegs. The game is targeted at development of logical thinking. The process of the decoding can be realized also using computer. Mathematical analysis, strategy solution, algorithm development of solution and computer simulation program in MS Excel of decoding of the color regardless of the position ordering are shown in the paper.