"Science" (Published 20220902) One -week thesis Guide

Compilation | Feng Weiwei

Science, 2 SEP 2022, Volume 377 Issue 6610

"Science" September 2, 2022, Vol. 377, 6610

Physics Physics

On the Origins of Fat 13th in Crystalline Metallic Materials

Source of the fatigue intensity of crystal metal materials

Author: J. C. Stinville, M. A. Charpagne, A. Cervellon, S. Hemery, F. Wang, P. G. Callahan, V. Valle, T. M. POLLOCK

Link:

https://www.science.org/doi/10.1126/sclence.abn0392

Summary:

Circular deformation materials are more likely to break due to fatigue. However, connecting fatigue intensity with micro structure has always been a challenge. The author used nano -resolution digital images related technologies to observe the sliding positioning of various alloy surfaces.

They found that after a deformed cycle, the amplitude of the early period of the bureau's ministry determines the fatigue intensity. This discovery helps to provide a physical foundation for well -known fatigue laws and pave the way for prone to predicting fatigue intensity.

Abstract:

Materials that are cyclically deformed become easier to break due to fatigue. However, tying fatigue strength to microstructure has been challenging. Stinville et al. used nanometer-resolution digital image correlation to observe the slip localization on the surface of a wide range of alloys. They found that after one deformation cycle, the amplitude of the early slip localization events determines fatigue strength. This observation helps to provide a physical basis for well-known fatigue laws and paves the way to easily predicting fatigue strength.

Magnetoelectric Transfer of a Domain Pattern

Magnetic Division of Magnetic Mode

Author: ehsan hassanpour, yannik zemp, yusuke tokunagayasujiro taguchi, YOSHINORI Tokura, Thomas Lottermoser, Manfred Fiebig, and MADS C. Weber

Link:

https://www.science.org/doi/10.1126/sclence.abm3058

Summary:

Multi -iron -based materials usually have two coupling sequence parameters, magnetization and electrode, and these two parameters can be controlled by the external field. The author studied multi -iron DY0.7TB0.3Feo3, which has an additional sequential parameter, which originated from the anti -iron magnetic order in the surface. The researchers created a model of iron magnetism and applied an external magnetic field to eliminate the existing model. However, in the polarization of the system, it created a same shape, minimizing freedom. This process can be reversed by applying electric fields.

Abstract:

Multiferroic materials are often characterized by two coupled order parameters, magnetization and electrical polarization, which can be controlled by external fields. Hassanpour et al. studied the multiferroic Dy0.7Tb0.3FeO3, which has an additional order parameter stemming from in-plane antiferromagnetic ordering . The researchers created a ferromagnetic multidomain pattern and applied an external magnetic field, which erased the existing pattern but created one of the same shape in the system's polarization, minimizing the free energy. The process could be reversed by applying an electric field.化学Chemistry

Late-Stage Diversification of Indole Skeletons Through Nitrogen Atom Inserty

Insert nitrogen atom in 子

Author: Julia C. Reisenbauer, Ori Green, Allegra Franchino, Patrick Finkelstein, and Bill Morandi

Link:

https://www.science.org/doi/10.1126/sclence.add1383

Summary:

Many pharmaceutical compounds contain a five -pointer or six yuan rings composed of carbon and nitrogen. Therefore, in the process of drug development, these mutual conversion chemical reactions are very useful.

Reisenbauer and others proposed a way to insert a nitrogen atom into the five -yuan rings protected by the silicon -based, so as to expand them into six yuan azodoline or chimodoline compounds according to their first replacement mode. This chemical reaction depends on the use of high -priced iodine to generate nitro, and is compatible with many common officials.

Abstract:

Numerous pharmaceutical compounds contain five- or six-membered rings composed of carbon and nitrogen. Chemical reactions that interconvert these motifs can therefore be very helpful during drug development research. Reisenbauer et al. present a method to insert a nitrogen atom into the five-membered rings of silyl-protected indoles, thereby expanding them into six-membered quinazoline or quinoxaline compounds depending on their substitution pattern at the outset. The chemistry relies on nitrene generation using hypervalent iodine and is compatible with many common functional groups.

3D Nanoprinting of Smiconductor Quantum Dots by PhotoexCitation-Induced Chemical Bonding

Semiconductor quantum dot three -dimensional nano -printing

Author: Shao-FENG LIU, Zheng-Wei Hou, Linhan Lin, Fu Li, Yao Zhao, xiao-Ze Li, hao zhang, hong-hua fang, zhengcao li, hong-bo sun, ETC.

https://www.science.org/doi/10.1126/sclence.abo5345

Summary:

The assembly of nanoparticles usually require targeted ligands so that they can selectively combine, just like combining complementary DNA chains. Alternatively, they can be connected together at the specified position through light to connect the ligand at the required position.

However, this process increases the complexity of preparing nanoparticles and is limited by the preservation of the ligand. The author's research shows that light can be used to unravaponate surface sulfur ligands from the selenium cadmium/zinc sulfide nuclear shell quantum dot. The resulting cave -grounded acupoint is combined between the remaining surface ligands.

The author reveals the light printing of any three -dimensional structure that exceeds the diffraction limit and the nanocheng range. Printing can be optical selection according to the size and/or gap of the quantum dot.

Abstract:

Nanoparticle assembly often requires tailored selection of the ligands so that they can selectively bond, as with complementary DNA strands. Alternately, they can be linked together at specified locations using photopolymerization to connect ligands at desired places. However, this process adds to the complexity of making the nanoparticles and is limited by the fidelity of the ligand attachment. Liu et al. show that light can be used to desorb surface thiolate ligands from cadmium selenide/zinc sulfide core shell quantum dots. The resulting trapped holes drive bonding between the particles through the remaining surface ligands. The authors reveal photoprinting of arbitrary three-dimensional architectures at a resolution beyond the diffraction limit and for a range of nanocrystals. Printing can be optically selected based on the size and/or bandgap of the quantum dots.

The Human Oxidation Field

Human oxidation field

Author: Nora Zannoni, Pascale S. J. LAKEY, Youngbo Wonmanabu Shiraiwa, Donghyun Rim, Charles J. WeschlerJing Wang, Lisa Eric, Mengze Li, Jonathan Williams

Link:

https://www.science.org/doi/10.1126/science.abn0340

Summary:

Hydroxyl radical (OH) is a highly active substance and is the main cause of oxidation of most polluting vascular gases. Outdoors, OH Freejee is mainly formed by the light dissolution of the light of the short wavelength of the solar light, but most of these light is filtered out by glass windows. So what is the OH free radical environment in the room?

The author said that when people are exposed to the indoor ozone of the climate, a high concentration of OH free radicals will be found, which is the product of the skin oil horn sharkne. Their discovery has an impact on indoor air quality and eventually affects human health. Abstract:

Hydroxyl radicals (OH) are highly reactive species that are responsible for the oxidation of most pollutant gases. Outdoors, OH radicals are formed primarily by the photolysis of ozone by short-wavelength sunlight, but that light is largely filtered out by glass windows, so what is the indoor OH radical environment like? Zannoni et al. report that high concentrations of OH radicals were found when people were exposed to ozone in a climate-controlled chamber, and were a product of a reaction with the skin oil squalene. Their finding Has implications for indoor Air Quality and Ultimately for Human Health.

Climatic climatology

A climate risk analysis of all ’s forests in the 21st Century

Analysis of the 21st Century Earth Forest Climate Risk Analysis

Author: William R. L. Andregg, Chao Wu, XNEZHA ACIL, NUNO Carvalhais, Thomas A. M. PUGH, Jon P. Sadler, and Rupert Seidl

Link:

https://www.science.org/doi/10.1126/sclence.abp9723

Summary:

Climate change has a negative impact on the forest through extreme high temperature, drought and interference. The impact of future climate change on forests is challenging, because each method depends on hypothesis and incomplete data.

Andregg et al. Compared the results of the three main modeling methods of information providing different aspects of information: It is estimated that the global mechanical vegetation model of forest carbon losses; climate package models that provide species change information; Evaluate.

These methods provide supplementary information, but they also emphasize that the overall risks facing forests in the south, dry tropical areas and China Europe are very high.

Abstract:

Climate change is having negative effects on forests through extreme heat, drought, and disturbances. Predicting the impact of future climate change on forests is challenging because each approach relies on assumptions and incomplete data. Anderegg et al. compared results from three major modeling approaches that provide information on different facets of risk: a global mechanistic vegetation model, which estimates forest carbon loss; a climate envelope model, which provides information on species shifts; and empirical assessment of forest loss to disturbance using satellite imagery. These approaches provide complementary information but Highlight the high overall risk to forests in the southern infal, DRY Tropics, and Central EUROPE. Edit | Fangyuan

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