除了因为持有财政部发行的铸币以外 还有别的途径显示在资产方的现金项目中吗

Every year, the Congress passes a bill for coming year's budget.
After president's approval, it will come into effect.
It is called appropriation.

This is the money "given" to the governments and its agencies (at different levels) for their yearly operation.
Of course, you won't see the physical money at all.
The money is 'stored' in the Department of Treasury.

After the program expenses or expenditures are being realized,
the department of Treasury will pay the bill via check format.
The correspondent journal entry will also be made at that time.

It's under assets category.