Nature, April 28th, 2022, Vol.604, No.7907.

Nature, April 28, 2022, Volume 604, No.7907.

Astronomy astronomy

Early solar system instability triggered by gas disk diffusion

The dissipation of the gas disk triggered the instability of the early solar system.

Authors: Liu Beibei, Sean N. Raymond &; Seth Jacobson

Link:

/articles/s 4 1586-022-04535- 1

abstract:

Here, we use dynamic simulation to illustrate that the instability of giant planets may be triggered by the dissipation of gas disks. When the gas disk evaporates from the inside to the outside, its inner edge sweeps in turn, which in turn dynamically disturbs the orbits of the planets. The related orbital motion leads to dynamic compression outside the system, which eventually leads to instability.

Within the feasible range of astrophysical parameters, the final orbit of our simulation system matches the orbit of the solar system. Therefore, the instability of giant planets occurs when the gas disk dissipates. According to astronomical observation, this is millions to 10 million years after the birth of the solar system.

Until such an early giant planet is unstable, the formation of earth-like planets is not complete; The growing terrestrial planets may even be shaped by their disturbances, which explains why Mars is relatively small in mass.

abstract:

Here, we use dynamic simulation to show that the instability of big planets may be caused by the diffusion of gas disks. When the disk evaporates from the inside out, its inner edge sweeps continuously, and the orbit of each planet is disturbed dynamically in turn. The related orbital movement leads to dynamic compression outside the system, which eventually leads to instability. For a series of feasible astrophysical parameters, the final orbit of our simulation system matches the orbit of the solar system. Therefore, the instability of this giant planet occurred when the gaseous disk dissipated, and astronomical observations limited it to several million to ten million years after the birth of the solar system. The formation of earth-like planets will not be completed until such an early giant planet is unstable; The growing terrestrial planets may even be shaped by their disturbances, which explains the small mass of Mars relative to the Earth.

Physics physics

Observation of quantum state of link in topological magnet

Observation of quantum state of link in topological magnet

Authors: Ilya BeLoppol, Guo Qing Chang, Taylor A Cochrane, Cheng Zijia, etc.

Link:

/articles/s 4 1586-022-045 12-8

abstract:

Here, we report that an unusual number of connections (kink theory) invariant is related to the cross ring of electron bands in mirror symmetric ferromagnets. Using the most advanced spectral method, we have directly observed three entangled degenerate rings in Brillouin zone of material tricycles T3.

We find that each ring connects the other rings twice. By studying the quantum state of this link through the system spectrum, we clearly draw its chain diagram, and compare it with the junction theory, and get that its chain number is (2,2,2), and directly determine its invariant structure from the experimental data.

We further predict and observe the seifert boundary state on the sample surface, and the sample surface is protected by volume connection, which shows that there is a significant seifert volume boundary response. Our observation of quantum ring chain promotes the application of kink theory in exploring magnetic and superconducting quantum matter.

abstract:

Here, we report an unusual number of links (kink theory) invariant, which is related to the cross ring of electron bands in mirror symmetric ferromagnets. Using the most advanced spectral method, we directly observed three entangled degenerate rings in the Brillouin zone of the tricyclic T3 body of the material. We found that each loop is linked to other loops twice. By studying the system spectrum of the quantum state of this linked ring, we clearly draw its link diagram, and draw a conclusion that, similar to the knot theory, it shows the number of links (2, 2, 2) and provides an invariant structure directly determined from the experimental data. We further predict and observe that the Seifert boundary state is protected by the body connection ring on the surface of our sample, suggesting a significant Seifert body-boundary correspondence. Our observation of quantum ring chain promotes the application of knot theory in exploring magnetic and superconducting quantum matter.

Field-free josephson diode in van der Waals heterostructure

Josephson diode without magnetic field in van der Waals heterostructure

Authors:,, Wang, Pranava K. Siwakuma, Chris Pascoe, Uldrik Filippozzi, Stuart S.P. Parkin, Zeng Yujia, Tyrell mcqueen &; Madzar Ali

Link:

/articles/s 4 1586-022-04504-8

abstract:

Here, we realize Josephson diode by fabricating the antisymmetric Van der Waals heterostructure of NbSe2/Nb3Br8/NbSe2.

We prove that even without a magnetic field, the junction can be superconducting under positive current and resistive under negative current. Δ IC behavior (the difference between positive and negative critical currents) is symmetrical with the magnetic field, and Josephson coupling can be proved by Fraunhofer model.

At the same time, we realize the stable half-wave rectification of square wave excitation with extremely low switching current density, high rectification ratio and high robustness. This nonreciprocal behavior strongly violates the known Josephson relation, which opens the door for discovering new mechanisms and physical phenomena through the integration of quantum materials and Josephson junctions, and provides a new way for superconducting quantum devices.

abstract:

Here, we realize the Josephson diode by fabricating the anti-symmetric van der Waals heterostructure of NbSe2/Nb3Br8/ NbSe2. We prove that even without a magnetic field, the junction can be superconducting under positive current and resistive under negative current. Δ IC behavior (the difference between positive and negative critical currents) is symmetrical with the magnetic field, and Josephson coupling is proved by Fraunhofer pattern. In addition, the stable half-wave rectification excited by square wave is realized with very low switching current density, high rectification ratio and high robustness. This nonreciprocal behavior seriously violates the known Josephson relation, and the integration of quantum materials and Josephson junction opens the door to discuss new mechanisms and physical phenomena, and provides a new way for superconducting quantum devices.

Chemical chemistry

Machine learning aided engineering of hydrolase for PET depolymerization

Machine learning aided engineering of PET degrading enzyme

Authors: Lu Hongyuan, Daniel J. Diaz, Natalie J. czarnecki, Zhu Congzhi, etc.

Link:

/articles/s 4 1586-022-04599-z

abstract:

Here, we use the structure-based machine learning algorithm to design stable and active PET hydrolase. Compared with wild-type petase, our mutant combination (fast PETase: PETase with functionality, activity, stability and tolerance) contains five mutations, and shows excellent PET hydrolysis activity in the range of 30-50℃ and a series of pH levels, compared with wild-type and engineering substitutes.

We have proved that almost all second-hand pets from 5 1 consumers can be completely degraded by FAST-PETase within 1 week. FAST-PETase can be used in 50? C, depolymerizing the untreated amorphous part of the commercial water bottle and the whole thermally pretreated water bottle.

Finally, we show a closed-loop PET recovery process, which uses fast enzymes and recycled monomers to synthesize PET. In a word, our research results provide a feasible way for the industrial recovery of enzyme plastics.

abstract:

Here, we use a structure-based machine learning algorithm to design a robust and active PET hydrolase. Compared with wild-type PETase, our mutant and scaffold combination (FAST-PETase: Functionality, Activity, Stability and Tolerance PETase) contains five mutations (from the predicted N233K/R224Q/S121E and from the scaffold D 186H/ R280A). And a series of pH values. We proved that almost all untreated post-consumption PET from 5 1 different thermoformed products can be completely degraded by FAST-PETase in 1. A week. FAST-PETase can also depolymerize the untreated amorphous part of commercial water bottles and the whole thermally pretreated water bottle of 50C. Finally, we demonstrated the closed-loop PET recycling process by using FAST-PETase and synthesizing PET from recycled monomers. In a word, our results prove the feasible way of enzymatic plastic recycling on industrial scale.

Computer-designed method for converting chemical waste into medicine

Calculation and design scheme of turning chemical waste into treasure

Author: Agnes Kavo? Operating system, Dominik, Coetzee, Lefsky, Rafa? Rozak, Sarah Sinku? And others.

Link:

/articles/s 4 1586-022-04503-9

abstract:

A large amount of chemical waste is constantly produced in the chemical industry, so it is necessary to design a "recycling chemistry" scheme to effectively convert waste into valuable products. Here, we show how computers with extensive comprehensive knowledge can help solve this challenge.

Using Allchemy platform for forward synthesis, we generate a huge synthesis network from about 200 kinds of commercial-scale recycled waste chemicals, and recover tens of thousands of ways from these networks, which can produce about 300 kinds of important drugs and pesticides, and then rank these compounds through algorithms according to the recognized indicators of sustainable chemistry.

Through experiments, we have verified several methods, including the demonstration of industrial reality on the platform of "on-demand pharmacy" flow chemistry. The extensive use of this waste utilization algorithm can accelerate the productive reuse of chemicals, thus avoiding the cost of waste storage or disposal and even the possible environmental harm.

abstract:

Because the chemical industry is constantly producing a large number of waste chemicals, it is necessary to design a "recycling chemistry" scheme to effectively reverse-convert at least some of these unnecessary materials into useful products. Here, we show how computers equipped with extensive synthetic knowledge can help meet this challenge. Using the forward-synthesis Allchemy platform, we generate a huge synthetic network from about 200 kinds of waste chemicals recovered on a commercial scale, retrieve tens of thousands of routes from these networks, and get about 300 kinds of important drugs and agricultural chemicals, and rank these syntheses through algorithms according to the recognized indicators of sustainable chemistry. We have verified several of these routes through experiments, including the demonstration of industrial reality on the platform of "pharmacy on demand". The extensive use of computerized algorithm to turn waste into treasure can accelerate the productive reuse of chemicals, otherwise it will lead to storage or disposal costs and even environmental hazards.

Catalytic synthesis of phenols by nitrous oxide

Catalytic synthesis of phenolic compounds by nitrous oxide

Authors: Franck Le Vaillant, Ana Mateos Calbet, Silvia Gonzá lez-Pelayo, Edward J. Reijerse, Sheng, Julia Busch &；; Joseph Conella

Link:

/articles/s 4 1586-022-045 16-4

abstract:

Here, we report that N2O is inserted into Ni-C bond under mild conditions (room temperature, 1.5-2 bar N2O), thus releasing valuable phenol and benign N2. This completely different organometallic C-O bonding step is different from the current methods based on reduction and elimination, and makes it possible to convert aromatic halogenated hydrocarbons into phenol by alternative catalytic methods.

In this process, the nickel center is catalyzed by bipyridine ligands. This method is stable, mild and highly selective, and can adapt to the function of alkali sensitivity, and allows the synthesis of phenol from highly functionalized aromatic halides.

Although this method does not provide a solution to reduce nitrous oxide emissions, it provides a blueprint for moderately revaluing nitrous oxide-rich as an oxygen source.

abstract:

Here, we report the insertion of N2O into Ni? C bonding under mild conditions (room temperature,1.5–2? Except N2O), thus transporting valuable phenol and releasing benign N2. This completely different organometallic c? The O-bond formation step is different from the current strategy based on reduction and elimination, and makes it possible to convert aryl halides into phenols by alternative catalytic methods. This process is catalyzed by a bipyridyl ligand with a nickel center. This method is robust, mild and highly selective, which can adapt to alkali-sensitive functional groups and allow the synthesis of phenol from densely functionalized aryl halides. Although the agreement does not provide a solution to reduce N2O emissions, it represents a reactive blueprint for moderate re-evaluation of abundant N2O as O source.