According to a report by the Physicist Organizations Network on December 13 (Beijing time), recently, Japanese physicists have broken through limitations in laboratory conditions during the study of crystal growth under zero-gravity conditions, using helium-4 superfluids on aircraft. The liquid produced neodymium crystals up to 10 mm in length and examined the special kinetics of the growth of germanium crystals over a wider range of conditions, which is not achievable with common materials. Related papers were published on the day of the New Journal of Physics.
The germanium crystal is grown by superfluid liquid splashing at a very low temperature of 0.6K (about minus 272°C) using high pressure. Superfluid liquid is a kind of quantum state substance, its nature is like liquid but its viscosity is zero, so it can also be unimpeded under high pressure. The superfluid liquid can flow through tiny gaps without any frictional resistance.
The crystal growth process is also referred to as "Ostwald ripening", ie, in solution, smaller crystals dissolve and re-deposit on larger crystals. “Ostwald ripening is usually a very slow process and can hardly be seen in larger crystals for a short period of time,†said the leading author of the paper and Professor Nomura Nomura of Tokyo Institute of Technology. “For ordinary traditions It may take thousands of years for the crystals to form a final fixed shape, and the low-temperature crystals can reach their final shape in 1 second.In general, when the crystals grow beyond 1 mm, they will deform due to gravity. Why do we need to do this experiment on the plane?"
When the aircraft is on a special trajectory, that is, flying along a parabola, the gravity on the airplane is zero. The researchers conducted experiments on a small jet aircraft in cooperation with the Japan Aeronautical Research and Development Agency (JAXA). The aircraft can provide 20 seconds of zero gravity conditions. In a two-hour flight, it can do about 8 experiments.
They designed a special small refrigerator on the plane with a window to observe the crystal formation. They put a large germanium crystal in a high-pressure chamber and use sound waves to break it up into tiny particles. Then they are poured into the helium-4 superfluid solution. The smaller particles melt, and the larger ones grow rapidly and form quickly. A 10 mm long independent crystal.
“The germanium crystals can grow very quickly from the superfluid solution because the germanium atoms are carried by a very fast and superfluid liquid and the crystallization process is not hindered. This is an ideal material for studying the fundamental problems of crystal formation because The crystallization speed is very fast," says Long Si. This study helps people to understand the basic physical mechanisms behind crystal growth, and also reveals some phenomena hidden under gravity. (Reporter Chang Lijun)
Economical Injection Masterbatches are the most common Black Masterbatch. This black masterbatches are made with recycle PE/EVA carrier, has low or middle carbon black, has calcium carbonate. It has the advantages on the prices, and universal applications for PE production, such as blowing film, injection, extrustion, molding so on.
Economical Injection Masterbatches
Injection Black Masterbatch,Economy Injection Masterbatch,Plastic Masterbatch For Injection,Injection Machinery Black Masterbatch
Anda Masterbatch( Group) Co., Limited , http://www.polymer-masterbatch.com