Using the bond-propagation algorithm, we study the critical Ising model on the square lattice with the shape of right triangle and free boundaries. The length of short leg is $N$ and that of long leg is $M$. The aspect ratio between the two legs $\rho =M∕N$ is fixed. For six ratios: $\rho =1,2,3,4,8,16$, the critical free energy density, internal energy density and specific heat on the lattices with $30\le N\le 600$ are calculated. Based on these accurate data, we determine exact expansions of the critical free energy, internal energy, and specific heat. With these expansions, we extract the bulk, surface, and corner parts of the free energy, internal energy, and specific heat. The corner term in free energy density proportional to $lnN$ is consistent to the conformal field theory in the accuracy of $10^{-10}$ at the least. It is found that the edge terms in the internal energy proportional to $lnN$ related to the hypotenuse are the same for $\rho =1,2,3,4,8,16$, i.e. this term is geometry independent. However the edge terms in the specific heat proportional to $lnN$ are geometry dependent, i.e. they are different for different $\rho$. The corner terms in the internal energy and specific heat are also obtained.

使用键传播算法，我们研究了具有直角三角形和自由边界形状的方形晶格上的临界Ising模型。短腿的长度是$ñ$ 长腿的是 $\mathrm{中号}$。两条腿之间的长宽比$\rho =\mathrm{中号}∕ñ$是固定的。对于六个比率：$\rho =\mathrm{1个}，2，3，4，8，16$，晶格上的临界自由能密度，内部能量密度和比热 $30\le ñ\le 600$计算。根据这些准确的数据，我们确定临界自由能，内部能和比热的精确膨胀。通过这些扩展，我们提取了自由能，内部能和比热的主体，表面和角落部分。自由能密度的角项与$lnñ$ 与共形场理论在精度上是一致的 $\mathrm{1个}{0}^{-10}$至少。发现内部能量中的边项与$lnñ$ 与斜边相关的是相同的 $\rho =\mathrm{1个}，2，3，4，8，16$，即该术语与几何无关。但是，比热中的边项与$lnñ$ 是几何相关的，即它们因不同而不同 $\rho$。还获得了内部能量和比热的角项。