如图,在正三棱柱\(ABC-A_{1}B_{1}C_{1}\)中,侧棱长和底面边长均为\(1\),\(D\)是\(BC\)的中点.
\((\)Ⅰ\()\)求证:\(A_{1}B/\!/\)平面\(ADC_{1}\);
\((\)Ⅱ\()\)求\(A_{1}A\)与平面\(ADC_{1}\)所成角的正弦值;
\((\)Ⅲ\()\)试问线段\(A_{1}B_{1}\)上是否存在点\(E\),使\(CE⊥\)平面\(ADC_{1}\)?若存在,求 \( \dfrac {A_{1}E}{A_{1}B_{1}}\)的值,若不存在,说明理由.