The radioactive decay process involves alpha and beta decay sequences. We can break down the steps as follows:
The original \(^{230}_{90}Th\) nucleus undergoes alpha decay, emitting an alpha particle (\(\alpha\)). After this decay, the resulting nucleus is \(^{226}_{88}Ra\).
The \(^{226}_{88}Ra\) nucleus undergoes alpha decay again, resulting in \(^{222}_{86}Rn\), emitting another alpha particle (\(\alpha\)).
The \(^{222}_{86}Rn\) nucleus undergoes alpha decay to form \(^{218}_{84}Po\), emitting another alpha particle (\(\alpha\)).
The \(^{218}_{84}Po\) nucleus undergoes alpha decay to form \(^{214}_{82}Pb\), emitting yet another alpha particle (\(\alpha\)).
The \(^{214}_{82}Pb\) nucleus undergoes beta decay, emitting a beta particle (\(\beta\)), and transforming into \(^{214}_{83}Bi\).
The \(^{214}_{83}Bi\) nucleus undergoes beta decay again, emitting a second beta particle (\(\beta\)), and transforming into \(^{214}_{84}Po\), which is the final product.
Thus, we see that there are 4 alpha decays and 2 beta decays. Therefore, the ratio of the number of alpha particles to beta particles is:
\[ \text{Ratio of } \alpha \text{ to } \beta = \frac{4}{2} = 2 \]
The ratio of the number of alpha particles to the number of beta particles emitted in this process is \(2\).
A temperature difference can generate e.m.f. in some materials. Let $ S $ be the e.m.f. produced per unit temperature difference between the ends of a wire, $ \sigma $ the electrical conductivity and $ \kappa $ the thermal conductivity of the material of the wire. Taking $ M, L, T, I $ and $ K $ as dimensions of mass, length, time, current and temperature, respectively, the dimensional formula of the quantity $ Z = \frac{S^2 \sigma}{\kappa} $ is:
Let $ a_0, a_1, ..., a_{23} $ be real numbers such that $$ \left(1 + \frac{2}{5}x \right)^{23} = \sum_{i=0}^{23} a_i x^i $$ for every real number $ x $. Let $ a_r $ be the largest among the numbers $ a_j $ for $ 0 \leq j \leq 23 $. Then the value of $ r $ is ________.
Let $ y(x) $ be the solution of the differential equation $$ x^2 \frac{dy}{dx} + xy = x^2 + y^2, \quad x > \frac{1}{e}, $$ satisfying $ y(1) = 0 $. Then the value of $ 2 \cdot \frac{(y(e))^2}{y(e^2)} $ is ________.