| Intangible assets, net |
| (15) | Intangible assets, net |
The acquired intangible assets, all of which are being amortized, have
an average useful life of approximately 20 years. Intangible assets consist of the following as of June 30, 2026 and December 31, 2025.
| | | As of June 30, 2026 | | | | | Average
useful life | | Gross carrying
amount | | | Accumulated
amortization | | | Net carrying
amount | | | Technology license | | 20 years | | $ | 97,646 | | | $ | 91,472 | | | $ | 6,175 | | | Customer relationship | | 20 years | | | 552,246 | | | | 386,572 | | | | 165,674 | | | Patent technology | | 20 years | | | 163,288,486 | | | | 29,319,067 | | | | 133,969,419 | | | | | | | $ | 163,938,379 | | | $ | 29,797,111 | | | $ | 134,141,267 | |
| | | As of December 31, 2025 | | | | | Average
useful life | | Gross carrying
amount | | | Accumulated
amortization | | | Net carrying
amount | | | Technology license | | 20 years | | $ | 100,221 | | | $ | 94,586 | | | $ | 5,635 | | | Customer relationship | | 20 years | | | 593,273 | | | | 355,964 | | | | 237,309 | | | Patent technology | | 20 years | | | 168,845,947 | | | | 26,626,257 | | | | 142,219,690 | | | | | | | $ | 169,539,441 | | | $ | 27,076,807 | | | $ | 142,462,634 | |
Amortization expense for intangible assets is $4,771,194 and $4,624,214
for the six-months ended June 30, 2026 and 2025, respectively.
|