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Trade Accounts and Bills Receivable, Net (Tables)
12 Months Ended
Dec. 31, 2020
Trade Accounts and Bills Receivable, net [Abstract]  
Schedule of trade accounts and bills receivable

   December 31,   December 31, 
   2019   2020 
Trade accounts receivable  $12,517,626   $33,305,997 
Less: Allowance for doubtful accounts   (4,650,686)   (5,266,828)
    7,866,940    28,039,169 
Bills receivable   85,480    1,532,105 
   $7,952,420   $29,571,274 

Schedule of analysis of the allowance for doubtful accounts

   December 31,   December 31, 
   2019   2020 
Balance at beginning of year  $3,657,173   $4,650,686 
Provision for the year   1,613,402    1,656,128 
Reversal - recoveries by cash   (567,042)   (934,391)
Charged to consolidated statements of operations and comprehensive (loss) income  $1,046,360   $721,737 
Write off   -    (431,684)
Foreign exchange adjustment   (52,847)   326,089 
Balance at end of year  $4,650,686   $5,266,828