Chinses empire in Han , Tang and Ming

Larger doesn't mean greater or superior.

Any evidence? I do know a lot about Qing dynasty

1. In terms of killing of Han people during their invasion of China, the manchu 'equal' that of the Mongols.

2. Men was forced to shaved the top of their head bald and had pigtails. It destroy more than 1000 years of Han tradition.

3. Under Ming code, Slaves was treated as the same category as the a free right person.

No, there is a great amount of innovation, reform and technological progress in every major dynasties except Qing.

When Qing conquer China, they copy the entire administration structure and fiscal practice from Ming dynasty with little changes. Under them, technological  stagnant and falling behind European power. After the opium wars, China enter the "Century of humiliation" being bully by almost every Western powers, Japan and Russia.

I agree with you if imperialism can be defined as the policy of expansion of power. But, attempt to expand or expansion of influence would also be imperialist. Then, Ming may also be "imperialist" because it actively sought to expand its sphere of influence in Manchuria, Yuannan and some part of Tibet.    

I must say that Qing disregarded the development of firearm weapons i'd say, because we pretty much know that there had been variety of domestic development of firearms during Ming dynasty and less development from the Qing dynasty.

The Qing court deliberately and systematically hindered the development of the firearms. One issue they concerned was to ensure their superiority  over the rebels. Strict rules were made to ban the firearms owned by folks. In the other hand, with huge troops stationed and solid control over its territory, they have no momentum to further upgrade their arsenals, especially after they stroke back the Russians' incursion in Siberia. Just check the WUSONG fort in Shanghai, all of the cannons there were made in Ming dynasty. No a slight improvement was made in the following three hundred years. The fort was totally destoried by the British during the 1840 opium war.

Where have you got that definition from? One widely accepted definition of colonialism is when the centre forces the periphery, the colony, to provide raw materials in exchange for manufactured products, thus reducing the colony to the status of a mere supplier of one or very few goods, with all the social implications. The workers are the indigenous people, the administrators, lawyers, doctors, and policemen from the occupants.

And this is exactly the case in the resource rich East Turkestan and the strategically important Tibet now.

Apart from the fact, that the Chinese systematically colonize these lands with their people, trying to press the Tibetans and Uighurs into a minority status in their own lands.

Apart from the fact, that the Chinese make A-bomb test in their colonies...

That's your definition of imperialism? Chinese immigrating is imperialism? No, it is not. And still you have not provided any proof that Tibet provides only natural resources and its objective is to buy only manufactured products from China. Where did you get that from? The Chinese HAD made A-bomb tests in their peripherial territories, but that is at locations where there isn't any resources and people. According to that US is a colonizer too. Now no one makes A-bomb tests.

Since when is oppressing people, destroying Buddhist temples, and forbidding to show a picture of the Dalai Lama a tourist attrcation? 

For Han nationalistic tourists maybe...

That was during the communist era, in which China at the most can only be half imperialistic at most due to that the economic requirements of imperialism is not met. Since when did Buddhist temples get destroyed today? If anything, they are preserving/rebuilding them. And oppress? Seriously, minorities have much more rights than the majority in China, considering that so many Han is looking back to their family roots just so they can attain minority status.Tibet is a major tourist sight in China, like it or not. There are plenty of places to visit, and people both foreigners and from other parts of China visit it every yr. I really don't see signs such as "no dogs and Indians allowed" in Tibet as I do see in the colonies of previous imperialistic countries. It is merely inefficient to run a country. As for natural resources, Tibet's main one is wind and hydroelectric energy. Tibet gets it, refines it, and sells it. China does not manufacture energy into other products, obviously, unless you are talking about using those energy to make other products from other resources.