From building the biggest experiments the world has ever seen to rolling out the latest medical advances on a massive scale and pushing the boundaries of exploration from the deepest ocean to outer space - China's scientific ambitions are immense.Just a few decades ago the nation barely featured in the world science rankings. Now, in terms of research spending and the number of scientific papers published, it stands only behind the US. But despite this rapid progress, China faces a number of challenges. Here are two key science projects that illustrate its enormous strengths, as well as some of its weaknesses, and may help answer the question whether China can become a global leader in research.
At Beijing's science and technology museum children are running around, clambering inside a model of a space station, taking miniature rovers for a test drive and even having a go on a spinning gyroscope. "Space is fun and very cool," one little boy tells me. I ask him about his ambitions, and he pauses for a moment before deciding yes, he would very much like to head into space and become a Chinese astronaut - or taikonaut - when he grows up. China's space programme has certainly captured the imagination here, and there is a sense of national pride in the country's achievements.
Nestling in a vast natural crater, China's giant is about to come alive. A colossal, steeply curved dish glints in the sunlight, surrounded by jagged mountains that cut into the sky. Construction workers, busy putting the finishing touches to this structure, look tiny against the huge backdrop. This is the largest radio telescope ever built, measuring 500m (1,640ft) across.
Prof Peng Bo
"In China, in astronomy, we're far behind the world," says Prof Peng Bo, the deputy project manager of the Five-hundred-metre Aperture Spherical Telescope - or Fast for short. We used to have to go abroad, to use telescopes outside China. I think it's time for us to build something in China."
Situated in Guizhou Province, in the south-west of the country, Fast dwarfs all other radio telescopes. The former record-holder was the Aricebo Observatory, in Puerto Rico, with a diameter of 305m (1,000ft). The Lovell telescope at Jodrell Bank in the north of England measures 76m (249ft) across. This isn't simply one-upmanship - bigger really is better when it comes to radio astronomy.
While some telescopes, such as the Hubble Space Telescope, use light to see the visible Universe, a radio telescope is more like a giant ear "listening" for radio waves emitted by objects in deepest space. Like light, radio waves are a form of electromagnetic radiation - but they have extremely long wavelengths, ranging from about a millimetre to more than 100km in length. And because these cosmic signals have travelled for great distances in space they are also incredibly weak. This is why radio telescopes need to be big - the larger the dish, the more signals it can collect.
China's new telescope is so large that the team hopes it will pick up radio waves from the far reaches of the cosmos. The telescope will be searching for ancient signals of hydrogen - one of the building blocks of the early Universe - to try to understand how the cosmos evolved. It will also be hunting for new stars - in particular a rapidly rotating and extremely dense type of star called a pulsar - and it will even join the hunt for extraterrestrial life. "The search for extraterrestrial life is a very hot topic for every telescope - and also for the public. I think Fast can make a contribution," Peng says. It took 10 years of trawling through satellite images of the Chinese countryside to find a natural depression big enough to fit the telescope inside. But construction has taken place in record time - just over five years, and it's nearly complete.
The dish is made from 4,450 triangular panels that have been painstakingly lowered into place. While the structure in its entirety is too big to move, each of the panels can be adjusted. It means the telescope's surface can be re-angled to allow scientists to study the parts of the sky they choose.
Professor Nan Rendong
The man masterminding this ambitious project, Prof Nan Rendong of the National Astronomical Observatories at the Chinese Academy of Sciences, says the telescope has been the biggest challenge of his career. "Guizhou is a developing province and our site is remote, in a poor area of countryside," he explains.
All the heavy parts of the structure we had to transport from an industrial area, thousands of miles away, across these terrible winding roads." Sometimes the problems seemed to be insurmountable, he says, and at times, he wanted to give up. "In the end, though, we found a way."
In ancient times, China was a world leader in science, famed for four great inventions - the compass, papermaking, printing and gunpowder. But over the centuries, as the ruling dynasties placed more focus on the arts, progress stagnated. And in the 1960s, in the turmoil of the Cultural Revolution, things got even worse. Many intellectuals and academics were forced to move to the countryside, and most scientific research came to a halt. But projects like the Fast telescope are powerful symbols of a scientific renaissance. In 2013, China's research and development spending overtook Europe's and it is set to outstrip the US's by 2020. A recent assessment by the journal Nature revealed that in terms of the number of papers being published, China now ranks second in the world behind only the US.
Charlotte Liu, Springer Nature
"I think in China, there seems to be a sense of urgency. There's a feeling that in the last 100 years, we lost a lot of opportunities because we weren't doing research," says Charlotte Liu, managing director in China for the science publisher, Springer Nature. "And now there is this golden opportunity in terms of funding, in terms of societal recognition, of the role that can be played by science."
But for those living in the shadow of Fast, the telescope is bringing unwelcome changes. Villages located within 5km (three miles) of the telescope will be subject to a radio quiet zone. Some reports have suggested that thousands of people may be affected. Anything that could interfere with the telescope, such as mobile phones or wireless networks, will be banned, and although the government has offered compensation to those who want to leave, some are unhappy. One woman tells me it will be too difficult to live here, so she'll be moving soon. A man says that while he supports the project, he's unhappy with the amount of compensation being offered. It's not enough money to move to the city, he says, so he's decided to stay put for now.
The scientists say they accept that people are having to make sacrifices, but they hope that the telescope will help the area. "It will attract a lot of scientists and tourists, and it's also a very good model for education, for the next generations, and for Chinese industry," says Nan Rendong. The project is currently on time, ready for completion in September. Only once it's switched on will we see whether it can help China to reclaim its science crown.
A Pig Cornea Transplant Can Help the Blind to See
Inside a cavernous, brightly lit shed, row upon row of pigs snuffle and shuffle around in their pens. Pork is big business in China, and this farm in the Guangdong Province in the south of the country has 2,000 pigs. These animals are bred for their meat - but there's now a new use for the pig parts that aren't destined for the dinner table.
Pig Bred for its Meat and Corneas
(Pig Eyes in Jars Above)
Once the pigs are killed, their corneas - the thin, transparent films that cover the front of the eye - are removed from some of them and set aside, to be transplanted into humans.
A few hours' drive away is China's oldest, and largest, eye hospital - the Zhongshan Ophthalmic Centre. China accounts for a fifth of the world's blind people: about eight million of its 1.4-billion population.
Dr Yuan Jin
As Dr Yuan Jin walks around the busy ward, he tells me that corneal disease is responsible for between 3.5 and five million of these cases. Injury or infection of the cornea, if untreated, can eventually lead to loss of sight - and for many, the only hope is a transplant. But the waiting list is extremely long. Once the main source of organs in China was from executed prisoners. But last year, the government stopped this controversial practice, and instead began encouraging people to sign up to donate their corneas after death. Few, though, are choosing to do so. Yuan explains: "In China, people have traditional opinions. They don't like to give their corneas. This is the main reason why we can carry out just 5,000 cornea transplants a year."
Today he is examining the eyes of patients who have been given pigs' corneas. The Chinese government gave the go-ahead for this experimental procedure last year, and about 200 operations have now been carried out. Fifty-eight-year-old Wu Pinggui is one of the latest recipients. One of his corneas became infected after an insect flew into his eye. "I didn't take care of the injury and it got worse," he tells me. "My eyes became red, swollen and painful." Eventually he lost his sight in that eye - and subsequently lost his job as a security guard. Now, 24 hours after surgery, some sight is returning. I ask him if he was surprised to be offered an animal's cornea. "I wasn't too surprised, I trusted the doctor's decision," he says.
Just 35 years ago, the city of Shenzhen was a fishing village. Today it's been transformed into a hub for innovation, and China Regenerative Medicine International (CRMI), the company that has developed the new cornea procedure, has its laboratory here.
Dr Shao Zhengkang
"We tried many animals - goats, dogs, pigs and cows," says Dr Shao Zhengkang, the company's chief executive, explaining that it took 10 years of research. Finally we found the structure of porcine corneas is very similar to a human's." Inside the lab there are flasks filled with corneas that have been removed from the pigs. They are milky white and glutinous - and need to undergo a process called decellularisation. Essentially the pig cells are stripped away, removing the animal DNA, proteins and lipids.
Cornea Tissue with Pig Cells Before Removal
Anything that could cause the patient's body to reject the tissue has to go. All viruses and bacteria are also inactivated, to prevent any diseases crossing from the animals into humans.
Just the basic shape, the collagen scaffolding, of the cornea is left behind. Once transplanted, it is then repopulated with the patient's human cells. Shao shows me the final product. The cornea looks like a contact lens. CRMI has spent 1bn Chinese Yuen (£100m, or $150m) developing it, but Shao admits the treatment is still at an early stage. "It's very different from the traditional treatment. It's totally new. So it takes time to introduce to hospitals, patients and society," Dr Shao says. The company says the success rate for the operations is above 90% - about the same rate achieved with human transplants. But some believe that China is moving too quickly, without assessing the risks - or the ethics. Animal-to-human-transplantation is just one area where China is straying on to controversial ground. Work on stem cells, cloning and gene-editing of embryos is also making waves in the international scientific community.
In the hospital, Wu Pinggui's check-up has gone well. His eye is still a little red, but the healing process has begun. He says this will make a big difference to his life - and he hopes that when he's better, he'll be able to find a new job. "I think some people have the view that China is at a frontier in science, and therefore there's a lot of ambition and appetite to explore the latest technology," says Charlotte Liu from Springer Nature. "And therefore, in that context, the time and the effort required to debate, to discuss and fully understand the consequences before embarking on something is probably not entirely there." But she says increasing scrutiny from other researchers around the world does seem to be changing this. "Science is still relatively young in China," she argues. "And the culture of doing science and ethics needs time to develop and cultivate."