scholarly journals The dynamic evolution model and experimental study of gas permeability under multiple factors

2018 ◽  
Vol 36 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Guangzhong Sun ◽  
Runlin Zhang ◽  
Kunyun Tian
Information ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 138 ◽  
Author(s):  
Wu ◽  
Shao ◽  
Feng

The evolution of a collaborative innovation network depends on the interrelationships among the innovation subjects. Every single small change affects the network topology, which leads to different evolution results. A logical relationship exists between network evolution and innovative behaviors. An accurate understanding of the characteristics of the network structure can help the innovative subjects to adopt appropriate innovative behaviors. This paper summarizes the three characteristics of collaborative innovation networks, knowledge transfer, policy environment, and periodic cooperation, and it establishes a dynamic evolution model for a resource-priority connection mechanism based on innovation resource theory. The network subjects are not randomly testing all of the potential partners, but have a strong tendency to, which is, innovation resource. The evolution process of a collaborative innovation network is simulated with three different government behaviors as experimental objects. The evolution results show that the government should adopt the policy of supporting the enterprises that recently entered the network, which can maintain the innovation vitality of the network and benefit the innovation output. The results of this study also provide a reference for decision-making by the government and enterprises.


2017 ◽  
Vol 34 (5) ◽  
pp. 058902
Author(s):  
Ze-Jun Xie ◽  
Lu-Man Zhang ◽  
Sheng-Feng Deng ◽  
Wei Li

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Xuefeng Han ◽  
Tingxiang Chu ◽  
Minggao Yu ◽  
Jiangkun Chao ◽  
Zhihui Ma ◽  
...  

In order to study the dynamic change law of the porosity of the compacted broken coal under different axial stress loading, based on the environment of the broken and compacted coal in the gob, aiming at the influence of the porosity on the spontaneous combustion of the coal, combined with the fractal theory, the fractal model of the porosity of the broken coal is established. A self-designed “testing device for permeability evolution and spontaneous combustion characteristics of crushed coal under pressure” is used to carry out axial loading test on selected coal samples in the gob. By comparing and analyzing the calculated results of void dynamic evolution model and experimental data, it is found that the relative error of void dynamic evolution model is between 2.8% and 6.2%, which meets the engineering needs. According to the stress-strain curve, initial accumulation state parameters, fractal dimension of initial crushing, and particle size distribution, the change of porosity under different compacted conditions can be predicted by the model, which has certain significance for identifying the change of compacted broken coal porosity and analyzing the process of coal spontaneous combustion and oxidation.


2018 ◽  
Vol 127 (2) ◽  
pp. 415-432 ◽  
Author(s):  
Leilei Si ◽  
Zenghua Li ◽  
Yongliang Yang

2017 ◽  
Vol 13 (8) ◽  
pp. 155014771772864 ◽  
Author(s):  
Zhuo Yi ◽  
Xuehui Du ◽  
Ying Liao ◽  
Lifeng Cao

Space–ground integrated network, a strategic, driving, and irreplaceable infrastructure, guarantees the development of economic and national security. However, its natures of limited resources, frequent handovers, and intermittently connected links significantly reduce the quality of service. To address this issue, a quality-of-service-aware dynamic evolution model is proposed based on complex network theory. On one hand, a quality-of-service-aware strategy is adopted in the model. During evolution phases of growth and handovers, links are established or deleted according to the quality-of-service-aware preferential attachment following the rule of better quality of service getting richer and worse quality of service getting poor or to die. On the other hand, dynamic handover of nodes and intermittent connection of links are taken into account and introduced into the model. Meanwhile, node heterogeneity is analyzed and heterogeneous nodes are endowed with discriminate interactions. Theoretical analysis and simulations are utilized to explore the degree distribution and its characteristics. Results reveal that this model is a scale-free model with drift power-law distribution, fat-tail and small-world effect, and drift character of degree distribution results from dynamic handover. Furthermore, this model exerts well fault tolerance and attack resistance compared to signal-strength-based strategy. In addition, node heterogeneity and quality-of-service-aware strategy improve the attack resistance and overall quality of service of space–ground integrated network.


Fuel ◽  
2016 ◽  
Vol 180 ◽  
pp. 106-115 ◽  
Author(s):  
Yong Ma ◽  
Zhejun Pan ◽  
Ningning Zhong ◽  
Luke D. Connell ◽  
David I. Down ◽  
...  

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