superweapon research has more utility in pushing the envelope in civilian and space applications, than it does in making superweapons (although that's a nice bonus). the Chinese are not likely to ever use said superweapons, because a conflict that would require superweapon use is so very unlikely, in the present political and economic situation.
globalization has succeeded beyond the US Republicans' wildest wet dreams. over 90% of everything is now manufactured in China or elsewhere overseas, over half of everything is designed and/or developed overseas by multinationals, and the US produces very little domestically.
one of the unintended consequences of this is that the national debt now stands at 9 trillion USD, and a good chunk of that was borrowed from China (the US is now in the comical position of also owing money to Mexico - how the mighty have fallen). skilled jobs are being offshored as quickly as outsource recruiters can hire people, and India, China and Russia have lots of engineers to work on all the superweapon research the Chinese can afford (India and China are graduating tens of thousands of technology-degreed professionals every year); they have plenty trained technologists left over, to pick up offshored design and development work from the US.
the US and China are inseparable economically, and the prospect of conquering and occupying China is uniquely unappealing (1.2bn population, large standing army, cohesive society, nuclear weapons, advanced technology, vast and difficult geography, a long history of conflict and hardship...). US foreign policy has created a political environment that has resulted in the first Chinese-Russian mutual defense treaty ever (giving the Chinese first access to Russian weapons, research and technology), and China looks to remain totalitarian at least until it completes its transition to a post-industrial information and services economy, to go with its enormous manufacturing capacity.
the US has created a colossal Chinese tail, that now wags the American dog. anyone who complains about technology sold to the Chinese through the back door (i'm looking at you, Webster), has somehow failed to notice the bulk of knowledge transfer going out the front door.
the Chinese engineers that attended the conference, most likely gave presentations on the unclassified parts of the research, to troll for ideas to resolve some of the bugs and problems they have encountered during development. it is naive to think that they would discuss anything classified, or give out the full scope and progress of their research program.
additionally, when one considers the sorry state of US gov't security in general, and military security in particular (Windows server shares and ftp directories with all-access permissions, unprotected by firewalls, come immediately to mind), it is silly to pretend that the US has many secrets from the Chinese, especially because, with the US educational system in decline, many of the engineers working in the US are likely to be Indian, Chinese, Russian, or other foreign-born.
there's not much left to keep secret. the horse has bolted, folks, and the barn has rotted and fallen apart. there is no door left to close.
the country is owned, like the US colonies were owned by the British Empire, though for different reasons. US colonies were a market for British goods, a taxable population, a dumping ground for criminals and nonconformists, and a source of raw material and slaves; the present US is a market for Chinese goods, a source of intellectual property and industrial/economic expertise, and a good place to spend all that capital created by the Chinese economic miracle. Lenovo-IBM and Acer-Gateway buyouts are just a sneak preview of what is to come. in 10 to 20 years, the US will likely be a largely Hispanic nation working for Chinese-owned corporations, and considering the present US economic and financial situation, that would be the optimal, best-case scenario.
anyone in the US who wants to have a future in politics or management, would be wise to learn to speak Spanish, Mandarin, or both.