Near protocol published a white paper that dives deep into Nightshade (NEAR sharding design). https://nearprotocol.com/downloads/Nightshade.pdf
Dr. Zhou was glad to see that Near Protocol is adopting a similar technique in QuarkChain to address the hot shard problem caused by overwhelming cross-shard transactions from other shards.
Another discussion on the topic can be found in: https://ethresear.ch/t/moving-eth-between-shards-the-problem-statement/6597/8
Dr. Zhou also mentioned that such technique has been running in QuarkChain mainnet ([http://mainnet.quarkchain.io]) and used daily by a list of exchanges that support mainnet such as Upbit, Gate io, Kucoin, MXC, Piexgo etc.
If you have any questions, please let us know.