(Original title: Zheda denied R&D "invisibility clothing": technically impossible)
Recently, according to online video, a university in China has developed “invisibility clothing†and some netizens said the college is Zhejiang University.
According to online video, an old man started a "plastic sheet" and his lower body "disappeared."
After the old man retired his "Invisibility Cloak," his body "reappeared." Yesterday, experts at Zhejiang University considered the video as a late synthesis.
This version of the picture / WeChat "tiexue360" video screenshots
An old man holding a plastic cloth, facing the camera, unfolded and raised his head. In the picture, the old man “disappearedâ€, leaving only the flowers and trees in the background.
In the past few days, a video with the theme "Uncle instantly disappears" has caught the attention of the Internet. A number of self-reported WeChat public numbers said in the news that Zhejiang University successfully developed domestic "quantum invisibility clothing" that can be similar to the magic function of "stealth."
Yesterday, the Beijing News reporter confirmed from the Zhejiang University that although the research on stealth technology was initiated many years ago, the so-called “research results†of the network transmission has nothing to do with Zhejiang University. Stealth technology expert Ma Yungui, professor of the School of Optoelectronics Science and Engineering of Zhejiang University, said that stealth technology is theoretically completely feasible, but specific practices are still difficult. In particular, there is still a long way to go before civilian use can be achieved.
Inquiring into the Internet-made "Quantum Stealth Clothing"
In front of the camera, a well-dressed, smiling old man holds a “plastic sheet†in his right hand and picks it up from among the flowers and trees. Afterwards, the old man shakes open the “plastic sheet†and slowly lifts it toward the top of the head. As the “plastic sheet†rises, the old man gradually “disappearsâ€, leaving only the hand on the edge of the “plastic sheet†and “suspendedâ€. In mid-air.
Such a video has recently attracted widespread attention. “Uncle instantly disappeared†has quickly become a hot word on the Internet. The Beijing News reporter noted that many Weibo and WeChat public accountants claimed that the old man is not a “plastic cloth†but a “quantum invisibility cloak†that can realize the stealth function of the human body. It was developed by Zhejiang University. Item "major technological breakthrough."
However, doubts came along. Some people say that online video may be spliced, not “stealth,†and at the same time in the video, “Some leaves are motionless†is proof. An industry insider who is engaged in video production told the Beijing News reporter that from the screen effect, this video should be edited using keying technology. The specific shooting process is: first take a no-man's empty mirror, and then the old man takes a blue or green cloth to shoot it once again, and compose the two videos together, and the blue or green cloth can be removed. “The bright spot on the video is the pinpoint of the map. This technique is very common in post-production.â€
The Beijing News reporter retrieved that as early as three years ago, foreign users had uploaded similar videos. However, at the end of the video, the so-called “Invisibility Cloak†is actually a green cloth, which is produced through post-synthesis.
Existing technology is insufficient to develop "invisibility clothing"
Yesterday, a staff member from the Zhejiang University told the Beijing News reporter that after the appearance of the online “China Quantum Invisibility Cloak†message, he had asked the experts in the field of stealth technology in the university to verify the case. The response was “I don’t know what’s going on. "Academic circles also have no literature and discussion in this area."
“Stealthy†technology expert Ma Yungui, professor of the School of Optoelectronics Science and Engineering of Zhejiang University, confirmed to the Beijing News reporter that Zheda did not develop domestic “quantum invisibility cloaks†and did not shoot video for release. Even “quantum invisibility cloak†itself is also a Pseudo concept. It said that under the current technical conditions, it is still impossible to produce "invisibility clothing" in online video. After watching the video, Ma Yungui also stated that he prefers the term "late synthesis".
The above-mentioned staff of Zhejiang University stated that the reason why the network-borne video was dubbed "Zheda University" was related to Zhejiang University's research on stealth technology.
The Beijing News reporter noted that in October 2013, Chen Hongsheng’s research team at Zhejiang University had published the paper “The Invisibility of Large Objects in the Visible Wave Band—Invisibility Mechanism of Electromagnetic Waves†in the authoritative scientific journal Nature Communications. However, the media reported at the time that this "stealth" technology principle was to minimize the reflection of electromagnetic waves by absorbing electromagnetic waves. The project team has stated that because of the technical bottlenecks of material parameters such as harshness and insufficiency, it is still very difficult to create stealth garments that are worn on the body.
â– Conversation
Ma Yungui, Professor, School of Optoelectronics and Engineering, Zhejiang University
"Invisible Cloth" Theoretically Feasible and Technically Difficult
Ma Yungui is a professor at the School of Optoelectronics and Engineering, Zhejiang University. He has long been researching new types of optical electromagnetic modulation technologies, artificial light electromagnetic materials and devices, and is also an earlier group of scientific research workers focusing on "stealth" technology. Ma Yungui told the Beijing News reporter that “hidden clothing†is currently entirely feasible in theory, but specific practices are still difficult and difficult to implement. In particular, there is still a long way to go to achieve civilian use.
"Technically temporarily unable to make 'Invisibility'"
Beijing News: Does the concept of "quantum invisibility cloak" really exist?
Ma Yungui: The academic world does not have the concept of "quantum invisibility clothing". The concept of "invisibility cloak" is something. This is a multidisciplinary research topic involving optics, electromagnetics, and mathematics.
Beijing News: So how can the authenticity of the "Invisibility Cloth" be transmitted?
Ma Yungui: This cannot be true, and there is no way to achieve such an effect technically. I have read some arguments and are more inclined to make videos using keying technology.
Beijing News: How to define "invisibility"?
Ma Yungui: Normally, people can see objects because the surface of the objects will scatter light. If the light can bypass the person, pass from the front to the back, and then completely restore the incident light, the “stealth†effect is achieved. For example, if the drop of water is directly above the glass ball, the water droplets spread across the surface, turning around the ball, and continuing to fall straight after converging in the lower half. If you can make light like a perfect turning process, you can achieve "stealth."
Beijing News: Is the definition of “stealth†consistent in scientific research and daily life?
Ma Yungui: Strictly speaking, the definition of “stealth†or “invisibility†in the scientific research and daily life is the same. It is achieved by allowing the light to perfectly bypass the object and continue to maintain the straight line transmission. ". However, in the field of scientific research, the category of concept of stealth will be broader. For example, the concept of “invisibility†means that no reflected echo can be detected, and it does not mean that “a perfect turn of light†must be achieved.
Beijing News: Why research "Invisibility Cloak" technology?
Ma Yungui: Scientific research generally has two driving forces. One is driven by scientific value. The other is driven by practical applications. Currently, stealth clothing technology is mainly driven by science. The scientific significance of this technology is relatively large, and it is expected to create disruptive applications in the future. . In this section, studies at home and abroad have been conducted almost at the same time. The challenges are also common.
"There is still a long distance to achieve civilian use."
Beijing News: What is the progress of the research on "invisible clothing"?
Ma Yungui: Recently we have achieved a new development that can make metal "stealth", such as through the security, so that the electromagnetic induction detector can not be effectively detected.
About "Invisibility Clothing" is theoretically completely feasible, and the relevant mathematical models and programs have actually been implemented. The key is whether or not they can be made. Is there a way to turn the theory into a solution? This piece is still relatively large. The challenge.
Beijing News: Where are the difficulties in research?
Ma Yungui: At present, we can verify the feasibility of the technology in local experiments, such as stealth at a certain frequency, or achieve stealth within a certain range of angles, but it is similar to "invisibility clothing" in this all-round, technically. Still can't do it.
The main reason is that light is a very complex physical quantity. At the same time, it is very challenging to meet its stealth needs. The “invisibility clothes†we refer to in the daytime actually refer to stealth in the visible light, but depending on the length of the band, the light can be divided. For infrared light, microwave, etc., all need to be studied.
Beijing News: What is the future application scenario of "Invisibility Cloak"?
Ma Yungui: Mainly concentrated in the field of national defense. The principle of the current "stealth plane" is that the fuselage absorbs all electromagnetic waves or reflects them to other places, making it impossible for radars to detect them. If similar "Invisibility Cloak" technology can be achieved, so that electromagnetic waves directly bypass the aircraft, then we can achieve a more ideal stealth effect.
Beijing News: So there is still a long distance from “Invisibility Cloak†to life?
Ma Yungui: Yes, there is still a long way to go to achieve "civilian" civilian use. The application of existing stealth technology is still military. This aspect of civilian use is still at the conceptual stage of scientific research and has not been directly applied.
Beijing News reporter Wang Hao
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