We report on two extensions of the traditional analysis of low-dimensional structures in terms of low-dimensional quantum mechanics. On one hand, we discuss the impact of thermodynamics in one or two dimensions on the behavior of fermions in low-dimensional systems. On the other hand, we use both quantum wells and interfaces with different effective electron or hole mass to study the question when charge carriers in interfaces or layers exhibit two-dimensional or three-dimensional behavior.
The Migdal effect inside detectors provides a new possibility of probing the sub-GeV dark matter (DM) particles. While there has been well-established methods treating the Migdal effect in isolated atoms, a coherent and complete description of the valence electrons in a semiconductor is still absent. The bremstrahlunglike approach is a promising attempt, but it turns invalid for DM masses below a few tens of MeV. In this paper, we lay out a framework where phonon is chosen as an effective degree of freedom to describe the Migdal effect in semiconductors. In this picture, a valence electron is excited to the conduction state via exchange of a virtual phonon, accompanied by a multiphonon process triggered by an incident DM particle. Under the incoherent approximation, it turns out that this approach can effectively push the sensitivities of the semiconductor targets further down to the MeV DM mass region.
Copper prices have surged in 2021. The base metal remains in high demand, much thanks to its need in green energy projects and electric cars. In May 2021, commodities analysts at Goldman Sachs called copper ‘the new oil.’ That’s because electric cars need several times more copper than their gas-powered counterparts. And power grids getting electricity from wind, solar and hydro sources also need copper—much more than the industry is currently producing. Here’s how copper became so important to the world economy and the green energy revolution.
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A team of researchers in the Faculty of Engineering of The University of Hong Kong (HKU) has developed a coin-sized system that can read weak electrochemical signals and can be used for personalized health monitoring and the measurement of such conditions as diabetes, cardiovascular diseases and mental health. The discovery was featured on the cover of Analytical Chemistry.
The PERfECT System—an acronym for Personalized Electronic Reader for Electrochemical Transistors—is the world’s smallest system of its kind, measuring 1.5 cm x 1.5 cm x 0.2 cm and weighing only 0.4 gram. It is easily wearable, for instance integrated with a smartwatch or as a patch, to allow for continuous monitoring of biosignals such as glucose levels and antibody concentrations in blood and even sweat.
“Our wearable system is tiny, soft and imperceptible to wearers, and it can do continuous monitoring of our body condition. These features mean it has the potential to revolutionize health care technology,” said Dr. Shiming Zhang of the Department of Electrical and Electronic Engineering, who leads the HKU WISE (wearable, intelligent and soft electronics) Research Group to develop the system.
Virginia is going from near-zero wind power to 2.6 gigawatts all at once, with the approval of a new offshore wind plan for Dominion Energy.
California is making waves with a big announcement of big plans for offshore wind, but the Golden State already hosts hundreds of wind turbines on shore. The really big news on the wind front is all the way across the country in Virginia, which has practically zero megawatts to its credit, onshore or off. That’s about to change all at once. Utility regulators in Virginia just stamped their seal of approval on a massive, Texas-sized offshore wind farm to the tune of 176 wind turbines totaling almost 2.6 gigawatts.
Wait, How Does An Offshore Wind Turbine Get To 14.7 Megawatts?
The new offshore wind farm comes under the umbrella of the Virginia-based company Dominion Energy, and we have questions.
Physicists have just caught light acting the part of ‘glue’ between atoms, in a kind of loosely bonded molecule.
“We have succeeded for the first time in polarizing several atoms together in a controlled way, creating a measurable attractive force between them,” says University of Innsbruck physicist Matthias Sonnleitner.
Atoms connect to form molecules in a variety of ways, all involving a trade of charges as a kind of ‘superglue’.
