How long can the standard model persist; the U.S. military releases the top ten black technologies of 2019 | weekly overview

2019-12-30 | Back to Park |


1. How long can the standard model persist?

2. Gene affects less than 5% of most diseases, including many cancers

3. Scientists develop antiferromagnetic topological quantum materials

4. New power to “turn on” chemical reactions

5. U.S. military releases top ten black technologies in 2019

edit | Yang Ling, Chen Hang

Compile | Gu Miaofei, Han Ruobing, Dong Weiyuan, Taigeer

1 How long can the standard model persist?

Harmonious and elegant basic particle standard model. After decades of beautifully supporting particle physics, with the discovery of neutrino oscillations 20 years ago, it is no longer doubtful that it will need to be revised and revised. Because China MicroThe fact that the sub-oscillation implies that it has a non-zero resting mass, which is not compatible with traditional standard models.

Every time an observational fact conflicts with an existing theoretical model, the enthusiasm of the relevant researcher will suddenly rise. In the past ten years, many discussions about how to expand the standard model have been the focus of continuous attention of high-energy physics researchers.As a result, many new theories have emerged to patch the standard model. BSM Beyond Standard Model and SME Standard Model Extensions have become the academic vocabulary, and are the most active areas in both theory and experiment.

For example, the more mainstream theory to explain the problem of neutrino mass is the "seesaw mechanism". This theory not only provides a theoretical description of the neutrino carrying mass, but also explains the problem of right-handed neutrino loss and why the left-handedThe mass of sexual neutrinos is much lighter than those of charged sister particles. Unfortunately, the mass of neutrinos is too small. Before a more accurate measurement, the seesaw mechanism is difficult to "real hammer". Moreover, this theory also requires that the neutrinos are horses.Yorana particles anti-particles are their own particles, which is also a conjecture that has not yet been concluded.

In terms of experiments, the LHCb hadron collision experiment and other high-energy experiments have accumulated a lot of data treasures. Researchers have tried to find signs of violation of the standard model from various angles. In 2015, R. Aaij of the LHCb laboratoryWhen analyzing their accumulated proton collision experiment data, their team found that Bs s is the subscript had abnormal anomalies that the standard model could not explain [1]. So the enthusiasm of related researchers was once again ignited.BSM / SME theory has emerged.

In a way, the anomalous decay of Bs s is subscript meson is more exciting than neutrino oscillation. Because the original neutrino problem does not involve charge, and the decay product of Bs s is subscript mesonIt is a charged neutrino relative. So many researchers have linked the two and speculated that the phenomenon of weak charge also known as the "taste" of particles is not unique to electrically neutral particles, and may be in its charged sister particles.Also appears.

The charged relatives of neutrinos are electrons, muons, and τons. These particles together with neutrinos are collectively called leptons. So the conjecture caused by the anomalous decay of Bs s is the subscript meson is also calledIt is LFV Lepton-flavor Violation. In the years after the experimental data were published, LFV is definitely one of the hottest topics in high-energy physics, and many related papers have been published [2-5].

In the following years, theoretical researchers extended the LFV to develop a more general guess that members of the lepton family are not equal and love as described in the standard model. This guess is calledLepton- universality Violation, if this theory can be verified experimentally, the most important modification to the standard model will be made since its birth.

Inspired by previous important discoveries, the R. Aaij team has been working hard to analyze various Bs s is subscript meson decay processes in recent years.

It is not difficult to predict that next year the team will continue to publish other permutations and combinations, and other researchers will continue to pay close attention to the release of analytical conclusions. Even if we go through all the processes in the future, we still have not found a new breakthrough, nor will weShake people's confidence and hope to continue to improve the standard model.

[1] R. Aaij, et al. LHCb Collaboration "Search for the rare decays B0 → J / ψγ and B0s → J / ψγ". Physical Review D. 92 11: 112002. 2015

[2] SL Glashow, D. Guadagnoli, and K. Lane, Lepton Flavor Violation in B Decays? Phys. Rev. Lett. 114, 091801 2015.

[3] D. Guadagnoli and K. Lane, Charged-lepton mixing and lepton flavor violation, Phys. Lett. B 751, 54 2015.

[4] I. de Medeiros Varzielas and G. Hiller, Clues for flavor from rare lepton and quark decays, J. High Energy Phys. 06 2015 072.

[5] A. Crivellin, L. Hofer, J. Matias, U. Nierste, S. Pokorski, and J. Rosiek, Lepton-flavour violating B decays in generic Z0 models, Phys. Rev. D 92, 054013 2015.

2, the effect of genes on most diseases is less than 5%, including multiple cancers

The latest research from the University of Alberta, Canada [1] shows that in most cases, the genes of an individual affect less than 5% of the risk of developing a disease.

A large number of studies have examined the relationship between common genetic mutations also known as single nucleotide polymorphisms or SNPs and different diseases and health conditions. Scientists have analyzed the research data in this field for more than two decadesCompleting this largest meta-analysis to date shows that the link between most human diseases and genetics is not significant.

"In short, DNA is not your destiny, and single nucleotide polymorphisms are not reliable predictions of disease," said David Wishart, one of the study authors. "For most diseases, including many cancers, diabetesAnd Alzheimer's disease, the genetic impact is at most 5% to 10%. "

The study also highlights some notable exceptions, including Crohn's disease, celiac disease, and macular degeneration, which have a genetic impact of about 40% to 50%.

Wishart explains: "Despite these rare exceptions, it is increasingly clear that the risk of most diseases comes from your metabolism, the environment, your lifestyle, and with various nutrients, chemicals, bacteria orVirus exposure. "

Wishart and research collaborators suggest that measuring metabolites, chemicals, proteins, or the microbiome can provide more accurate measures of human disease risk and help lead to more accurate diagnoses. This discovery challenges many modern genetic testsBusiness models, these services have suggested that genetic testing can accurately predict someone's risk of disease.

Wishart added: "This study also highlights our need to understand the environment, as well as the safety and quality of food, air and water."

[1] Patron J, Serra-Cayuela A, Han B, et al. Assessing the performance of genome-wide association studies for predicting disease risk [J]. PloS one, 2019, 14 12.

3.Scientists have developed antiferromagnetic topological quantum materials

Quantum materials are one of the most popular research directions in the world today. The reason for their popularity is mainly because this material exhibits many rich properties, such as magnetic properties, superconducting properties, and topological properties.Processing, sensing, computing and other fields have very broad application prospects. In particular, words such as quantum computing and quantum hegemony have frequently occupied the headlines in recent years.

A major drawback of quantum materials is that their extraordinary properties often require very harsh working environments, such as ultra-low temperature, extremely strong magnetic fields or extremely strong pressures, etc. This is obviously not conducive to the application of quantum materials. Therefore, scientists have recentlyConstant attempts have been made to make quantum materials achieve excellent properties at room temperature, normal pressure and no magnetic field. A material that can achieve this goal is called Magnetic Topological Insulators MTI. Theoretical predictionsShows that this material may be sufficient to exhibit unprecedented quantum characteristics, but it is extremely difficult to prepare such materials in the laboratory.

The shining peaks will never lack dedicated climbers. Dr. Anna Isaeva is a young professor at the Technical University of Dresden and the Leibniz Center for Solid State Physics and Materials Research. She is a professor of quantum material synthesis and crystal growth.An expert, her research group has prepared and researched various new types of quantum materials by combining knowledge of chemistry, physics, and crystallography. In recent years, Dr. Isaeva's team has worked with more than 40 scientists from 20 research units, dedicated toDevelopment of new quantum materials. In collaboration with Dr. Alexander Zeugner of the Leibniz Center for Solid State Physics and Materials Research, Dr. Isaeva's team developed a crystal growth method for quantum materials, and prepared and characterized the intrinsic magnetic topological insulator MnBi2Te4 2 and 4 are subscripts, and the results have been published in the journal Nature. [1] This material is composed of three elements: manganese, bismuth, and tellurium.The transition metal is prepared by doping non-magnetic topological insulator materials, and this process will cause non-uniformity in the electromagnetic properties of the material. And MnBi2Te4 24 is a subscript, which does not require elemental doping, and is an intrinsic antiferromagnetic topological insulator. This is theoretically proven by researchers from the Donostia International Physics Center in Spain.The team confirmed this with spectroscopic measurements.

This research is of great significance in science. The surface of a magnetic topological insulator crystal has an edge state, which can realize the quantum Hall effect without adding an external magnetic field. In addition, the above-mentionedThe synthesis of the antiferromagnetic topological insulator material has made a great contribution to today's emerging antiferromagnetic spintronics. In addition, there is also an emerging magnetic material called van der Waals material. ThisThis kind of material is a sheet-like two-dimensional material. The atoms in the layer are connected by strong covalent bonds, and there is a weak van der Waals force between the layers. Therefore, it is named [2]. Two-dimensional ferromagnetic materialFor example, the MnBi2Te4 introduced in this article 2 and 4 are subscripts is also very beneficial to the development of Van der Waals materials.

Dr. Isaeva's team has further optimized the method for synthesizing new quantum materials to make it easier to synthesize MnBi2Te4 2 and 4 are subscript single crystals. Researchers around the world are also working together to study MnBi2Te4 2 and 4 are subscripts The interaction between the magnetic and topological structures present in the material. Recent studies have shown that MnBi2Te4 2 and 4 are subscripts have more derived structures related to magnetic topological insulators.

Dr. Isaeva said: "We are witnessing the emergence of a new class of magnetic topological insulators, which do not rely on magnetic doping methods, but are achieved through intrinsic magnetization. Research on this type of material is currently being conducted worldwideThe competition is very fierce [3], and related academic papers have sprung up like mushrooms. "Dr. Isaeva's group has published three articles after the first one.

[1] Otrokov MM, Klimovskikh II, Bentmann H, et al. Prediction and observation of an antiferromagnetic topological insulator [J]. Nature, 2019, 576 7787: 416-422.

[2] Two-dimensional van der Waals materials, Physics Today 69, 9, 38 2016; doi: 10.1063 / PT.3.3297

[3] Note: MnBi2Te4 2 and 4 are subscripts related materials have been very popular research directions in recent years, and Chinese scholars have also made outstanding contributions in this field. For example, the Institute of Physics of the Chinese Academy of Sciences has reported a recentRelated work: Among them, Professor Xue Qikun's team is also the pioneer of this material as a related research on magnetic topological insulators.

4. New power to "open" chemical reactions

Researchers have confirmed that the use of mechanical forces can stimulate chemical reactions, and this is a more economical, more widely used, and more environmentally friendly method than traditional methods.

The most traditional way to increase the rate of a chemical reaction is to heat the reactants. In the past 10 years, scientists have also carried out a lot of research on photoredox catalysts, which can be activated by visible light, making the chemical reaction higher.Selectivity and efficiency. However, these reactions usually require the use of large amounts of organic solvents and are therefore only suitable for soluble reactants.

Piezoelectric materials, such as barium titanate, generate electric potential when pressure is applied, which is why they are used in mobile phones and lighters. In a recent study published in the journal Science [1], Hajimo Ito and Koji Kubota of the Institute of Chemical Reaction Design and Discovery, Hokkaido University, demonstrated that the potential generated by piezoelectric materials can also be used to activate chemical reactions. "In our reaction system, we use a ball mill to generate mechanical forces,After mechanical force is applied to the piezoelectric material, the redox reaction is successfully activated. "Koji Kubota said. Corresponding to the" light "redox reaction, they call this type of reaction" mechanical "redox reaction.

The research team obtained the potential from BaTiO3 3 is the subscript and used it to activate the aryl diazonium salt, resulting in highly activated groups. These groups can efficiently perform arylation and boronization[2]. The research team also found that the boronation reaction can occur even by hitting the reactants contained in the plastic bag with a hammer.

"The reaction system we use only needs to use a ball mill to generate mechanical force and no solvent. This method greatly reduces the use of organic solvents, making the reaction easier and more environmentally friendly. For those insoluble solventsThe same applies. "Koji Kubota said. They can also recover barium titanate with a higher yield than the photoredox reaction.

[1] Kubota K. et al. Science, December 19, 2019.

[2] Note: Arylation and boronization are two very important reactions in synthetic chemistry.

5, the U.S. military released the top ten black technologies in 2019

Recently, the U.S. Army CCDC Research Laboratory released a list of the ten coolest scientific and technological advancements in the military field in 2019 [1], let's poke the video to see it quickly!

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Video source: CCDC Research Laboratory of the US Army | Subtitle editing and production: Yang Ling

10th place

The use of plastic fiber muscles in robots has greatly improved the performance of robots.

9th place

Use wearable sensors to monitor soldiers' health and environmental hazards.

8th place

A new water-based refractory lithium-ion battery is being developed.

No. 7

Imagine that you can generate energy at any time with just one pill and water!

6th place

Using 3D printing technology to make super strong metal parts, we will not need to carry spare weapons in future wars.

No. 5

A brain detector under development to analyze soldiers' attention and brain activity.

4th place

AI system-CRYSTRAL helps the military develop high-density energy storage materials.

3rd place

A new type of radio command system adapted to complex battlefields.

2nd place

A material that can repair itself!

No. 1

A new type of robot brain is being developed to enable the robot to process various unknown objects in various unknown scenarios.


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