string[] result = Regex.Split(yourStr,@"(?<!^)(?=\D$?)");

------解决方案--------------------
C# code

private static string[] SplitString(string s)
{
    return Regex.Replace(s, @"(?<=\d)(?=[a-z])", ",", RegexOptions.IgnoreCase)
                .Split(',');
}

------解决方案--------------------
C# code

private static string[] SplitString(string s)
{
    return Regex.Split(s, @"(?<=\d)(?=[a-z])", RegexOptions.IgnoreCase);
}