People wait for their turn to get vaccinated against COVID-19 in Beijing. Photo: AP According to CNBC, within just 5 days of May, China injected 100 million doses of the COVID-19 vaccine to its people. Health officials hope to be able to vaccinate 80% of its 1.4 billion population by the end of 2021. As of June 2, China has injected a total of over 704 million doses of vaccine, of which half were administered in May. The total number of doses of COVID-19 vaccine that China has given to the population accounts for about one-third in one. ,9 billion doses of vaccine are distributed globally. The call to vaccinate is from all walks of life. Companies inject workers, schools urge students and teachers to immunize, local authorities urge people to vaccinate. According to Our World in Data, in 7 days, China is injecting an average of 19 million doses per day. With a population a quarter of China’s, the US only injected 3.4 million doses / day in April – when the vaccination campaign was operating at full speed. A medical worker administers a COVID-19 vaccine at a vaccination site in Shanghai, China. Photo: THX/VNA On May 30, Zhong Nanshan, the head of an expert group of the National Health Commission of China, said that 40% of the Chinese population has been vaccinated with at least one dose, and the government’s goal is to fully immunize all patients. this number at the end of June. In the capital Beijing, 87% of people have received at least one dose of the COVID-19 vaccine. Vaccination in Beijing is easy because there are hundreds of vaccination service points throughout the city. Vaccination buses are parked right in crowded areas such as city centers and commercial centers. However, vaccination in other areas is not as easy as in the capital. Ms. Zhou Hongxia, a resident of Lanzhou, Gansu province, said: “I started waiting in line for the injection at 9am and didn’t get the injection until 6pm. It’s tiring. When I returned, there were still people waiting.” Ms. Zhou’s husband couldn’t even schedule a vaccination. On May 31, government officials said they were working to ensure the supply of COVID-19 vaccine is distributed more evenly. Not only focusing on inoculating people in the country, China also injects its citizens abroad when donating vaccines to Thailand, part of which is used to vaccinate the Chinese before giving them to Thai people. Globally, China has injected more than 500,000 citizens abroad. Before the domestic vaccination campaign accelerated in recent weeks, many Chinese people were in no hurry to get vaccinated because China had almost no cases in the community thanks to tight border controls and mandatory isolation. Recently, China has appeared many small clusters of infection and is suppressing the cluster in Guangzhou. According to analysts, despite the uneven distribution of COVID-19 vaccines, Chinese manufacturers have hardly had problems with the scale of production. Both companies that produce most of the COVID-19 vaccines being used in China, Sinovac and Sinopharm, have drastically increased production, built new factories and converted existing factories to produce COVID-19 vaccines. . Vaccines of Sinovac Biotech (China) at a vaccination center in Bangkok, Thailand on May 12, 2021. Photo: THX/VNA Vaccines from Sinovac and one from Sinopharm have been approved for emergency use by the World Health Organization. “Where in the world can match China in terms of construction speed? How long does it take China to build field hospitals? Just a few days.” Sinovac said it has doubled production capacity to 2 billion doses/year, while Sinopharm said it can produce 3 billion doses/year. From the beginning of the year to the end of May, Sinovac produced 540 million doses of the COVID-19 vaccine. Government support is crucial for vaccine manufacturers at every stage. Sinopharm said that right from the start of the vaccine research, it had borrowed a laboratory at a government research center. Chinese vaccine companies largely do not depend on imported products in the production process, so the scenario of shortage of raw materials and ingredients like the Serum Institute in India should be avoided. As of June 4, China had 91,194 cases of COVID-19, of which 4,636 died.

Bran Castle. Photo: AP The AP news agency (USA) reported that a COVID-19 vaccination center has been set up at Bran Castle in the Transylvania region. This castle is the site where Irish writer Bram Stoker inspired Dracula’s “vampire’s home” in the 19th century horror novel “Dracula”. Accordingly, every weekend of May will take place the “vaccine marathon” program at Bran Castle. People who come for injections do not need to book an appointment. Pfizer’s COVID-19 vaccine recipients will receive free admission to the castle’s torture chamber, home to 52 medieval torture instruments. At the end of the first week of May, nearly 400 people went to Bran Castle for a COVID-19 vaccine. However, there is a rule that only Romanian people can get the COVID-19 vaccine for free. The program at Bran Castle is part of a series of initiatives by the Romanian government to promote the COVID-19 vaccine campaign in this country of 19 million people. The Romanian government hopes to be able to vaccinate 5 million people by June 1. From May 8, all vaccination centers in Romania apply the rule that no reservations are made after 2pm. According to the statistics of worldometers.info, as of 9 am on May 11, the total number of COVID-19 infections in Romania is over 1 million cases, of which 29,034 have died.

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I don’t know if you have seen a video similar to “Glass Marble Making”.

In the video, the worker master needs to heat the glass material at a high temperature and then quickly shape it in a fluid state.

Although we are across the screen, we will also sweat for the operator. After all, the bright brightness makes it very hot to look at!

However, a recent study by Science shows that Now it is possible to inject glass under low temperature conditions!

Frederik Kotz and Bastian E. Rapp of the University of Freiburg in Germany proposed a high-throughput injection molding process using silica nanocomposites.

They combined the low-temperature injection molding process (IM) with water-based degreasing and low-temperature sintering processes to develop a new glass processing technology compatible with injection molding technology, which can quickly mass produce high-precision glass products with smooth surfaces.

Processing glass is not that simple

This technological breakthrough can be said to solve the core difficulties of the current glass processing industry.

first of all, High temperature melting, castingIt has always been a problem that plagued the glass processing industry.

The high temperature requirement above 1500℃, on the one hand, causes huge energy consumption during processing (It is estimated that every ton of glass processing needs to consume 5-6 megajoules of energy); On the other hand, to a certain extent, it limits the capacity and efficiency of glass industrial processing.

Secondly, the processing of glass micro-morphology mostly uses hydrofluoric acid, laser etching, etc. The preparation process is dangerous, difficult to operate, and pollutes the environment. The shape and output that can be processed will also be limited.

How to achieve?

However, Markus Mader and others used a low-temperature injection molding process (IM) combined with a water-based degreasing and low-temperature sintering process, which just solved the above problems.

Technical core—— Injection molding process (IM)It is a kind of rapid processing technology suitable for industrialized production. It finally produces a semi-finished product with a certain shape by pressurizing, injecting, cooling, and detaching molten raw materials.

Previously, this technology was mostly used in the processing and production of polymers. This time researchers have applied it to glass processing in a breakthrough.

First, the researchers pre-mixed silica nanopowder, vinyl butyral (PVB) solution, and vinyl butyral (PEG) solution, and evaporated to obtain a thermoplastic silica composite.

Then use a twin-screw extruder to plasticize and extrude the obtained material to obtain granular raw materials;

Followed by 130°C, Injection molding at a specific pressure of 700 ~ 1000 bar, obtained Green bodysection;

Soak the green body in water at 40°C first to remove the PEG from the material, and then use high temperature to remove the remaining binder;

Finally, high-quality transparent fused silica glass is obtained by sintering in a vacuum environment at 1300°C.

Due to the optimized two-step degreasing process, the injection molded green parts (less than 2 mm in size) are converted to transparent fused silica, and only a total of 24 hours.

In addition, the researchers further used the technology to perform high-throughput manufacturing on a commercial injection molding machine (Babyplast Christmann).

It was found that even if the silica nanocomposite is fully automated injection molding with a cycle time as low as 20 seconds, it is possible to produce complex-shaped fused silica parts at the industrial production level.

More than 200 parts were produced in 18 minutes, which means One glass component can be produced every 5 seconds!

Not only that, the energy consumption of the whole process Less than 60% of traditional processing technology; And because the degreasing process is not carried out in a high temperature environment, the adhesive used in the process can still recycle and re-use.

△Frederik Kotz

Researcher Frederik Kotz said: “This method can finally get high-purity silica glass of any shape.” And said that these glass parts will eventually have Commercial telecommunications equipment and chemical reactorsThe required optical and chemical properties.

△André Studart

André Studart, a materials scientist at ETH Zurich, said that this method can lead to more new ideas.

However, he proposed that this new method of mass production of glass components still faces a bottleneck: The PEG removal process takes several days, To ensure that the glass parts will not crack.

“If this process is accelerated, glass injection molding will become as popular as plastic!”

Reference link

[1]https://science.sciencemag.org/content/372/6538/182

[2]https://www.sciencemag.org/news/2021/04/glass-molded-plastic-could-usher-new-era-complex-shapes

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