The method for proper determination of the time step and space interval is studied. Calculation of the gas emission rate according to gas pressure distribution is analyzed when finite difference method is applied to simulate the gas flow in coal seams. 对应用有限差分法解算煤层瓦斯流动时,如何选取合适的时间步长和空间步长、如何根据煤层瓦斯压力分布计算煤壁瓦斯涌出量等问题进行了分析和探讨。
This system can be driven from any initial state to any terminal state in proper space, if the time interval is long enough and the damp is small enough. 证明了在时间足够长而阻尼足够小的情况下可以通过控制边界上某一部分的振动过程使得整个区域内的波动系统在某种正则空间内从任意初始状态出发到达任意终止状态。
The former is reached mainly by adopting the Portland cement with middle or low heat, proper mix proportion of concrete, rational layer thickness, rational time interval and initial cooling of water; 减少浇筑层的水化热温升主要靠采用中低热硅酸盐水泥、较优的混凝土配合比,并采取合理的层厚、间歇期和初期通水冷却等措施来达到;
Firstly, the transmitter determines the proper time interval d according to the coherence time of the wireless channels. Then several signal vectors with an interval of d are combined together by a singular matrix, and the result vectors are transmitted at the corresponding time slots. 在该方案中,发射机根据信道相干时间确定合适的时隙间隔d,并利用奇异矩阵对多个相距d个时隙的信号矢量进行线性组合,从而得到系统在对应时隙的发射信号。