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Category: materials – Page 3

MIT engineers grow “high-rise” 3D chips

The electronics industry is approaching a limit to the number of transistors that can be packed onto the surface of a computer chip. So, chip manufacturers are looking to build up rather than out.

Instead of squeezing ever-smaller transistors onto a single surface, the industry is aiming to stack multiple surfaces of transistors and semiconducting elements — akin to turning a ranch house into a high-rise. Such multilayered chips could handle exponentially more data and carry out many more complex functions than today’s electronics.

MIT researchers fabricated 3D chips with alternating layers of semiconducting material grown directly on top of each other. The method eliminates thick silicon between layers, leading to better and faster computation, for applications like more efficient AI hardware.

Scientists discover a materials maze that prevents bacterial infections

Scientists at the University of Nottingham have discovered surface patterns that can drastically reduce bacteria’s ability to multiply on plastics, which means that infections on medical devices, such as catheters, could be prevented.

The findings of the study, which are published in Nature Communications, show that when bacterial cells encounter patterned grooves on a surface, they lose their ability to form biofilms.

Biofilms are surface-associated slime-cities which help protect the bacteria from the body’s natural defenses against . This, in turn, means the infection is effectively prevented before it can become fully established and would also positively activate the immune system to get rid of any individual bacteria that were there.

Scientists achieve 1,000-fold increase in solar electricity using ultra-thin layers

At the core of this discovery, published in Science Advances, is barium titanate (BaTiO₃), a material known for its ability to convert light into electricity, though not very efficiently on its own.

The scientists found that by embedding thin layers of barium titanate between two other materials – strontium titanate and calcium titanate – they could create a structure that produces significantly more electricity than barium titanate alone, even while using less of it.

The improvement is striking. The layered structures generated up to 1,000 times more electricity than the same amount of standalone barium titanate. The researchers were also able to fine-tune this effect by adjusting the thickness of each layer, giving them control over the system’s performance.

Thermodynamics revisited: Study solves 120-year-old problem and corrects one of Einstein’s ideas

The concatenation of both ideas allows us to conclude that entropy exchanges tend to zero when the temperature tends to zero (which is Nernst’s theorem) and that absolute zero is inaccessible.

Martin-Olalla points out that a fundamental problem in thermodynamics is to distinguish the sensation of temperature, the sensations of hot and cold, from the abstract concept of temperature as a physical quantity. In the discussion between Nernst and Einstein, temperature was merely an empirical parameter: the absolute zero condition was represented by the condition that the pressure or volume of a gas became close to zero.

Formally, the second principle of thermodynamics provides a more concrete idea of the natural zero of temperature. The idea is not related to any sensation, but to that engine imagined by Nernst but which has to be virtual. This radically changes the approach to the proof of the theorem.

Next leap in mode-locked lasers: Tunable pulse duration in ultranarrow bandwidth

Lasers have widespread applications as a light source in a variety of fields, including manufacturing, medicine, high-speed communications, electronics, and scientific research.

In recent years, the demand for lasers with increased control over their output has grown significantly. In particular, ultranarrow mode-locked lasers, which can produce extremely short laser pulses (short bursts of light) ranging from picoseconds to nanoseconds, have received considerable attention. Such are extremely beneficial for many applications—from diamond cutting to semiconductor manufacture. However, these applications can be further improved with the incorporation of lasers with tunable pulse duration.

A laser works by reflecting light back and forth between a highly reflective and a selective reflective mirror inside a cavity, and then amplifying it using a material called the gain medium. Conventional continuous-wave lasers emit a continuous beam of light waves (modes) with different wavelengths and random phases.

Nanoscale phonon dynamics in self-assembled nanoparticle lattices

The realization and phonon imaging of nanoscale mechanical metamaterials has remained challenging. Here the authors resolve the phonon dynamics and band structures of five different self-assembled nanoparticle lattices, revealing the role of nanoscale colloidal interactions in modulating the lattice properties.

What is uranium enrichment and how is it used for nuclear bombs? A scientist explains

Late last week, Israel targeted three of Iran’s key nuclear facilities—Natanz, Isfahan and Fordow, killing several Iranian nuclear scientists. The facilities are heavily fortified and largely underground, and there are conflicting reports of how much damage has been done.

Natanz and Fordow are Iran’s uranium enrichment sites, and Isfahan provides the raw materials, so any damage to these sites would limit Iran’s ability to produce .

But what exactly is and why does it raise concerns?

Artificial light in big cities is extending the growing season of urban plants, satellite observations show

Artificial light may be lengthening the growing season in urban environments by as much as 3 weeks compared to rural areas, according to an analysis of satellite data from 428 urban centers in the Northern Hemisphere over 7 years, published in Nature Cities.

Rapid urbanization is leading to hotter and brighter cities. More specifically, buildings and concrete absorb and radiate heat, causing urban heat islands, in which urban areas have higher atmospheric temperatures throughout the day and night compared to their surroundings. Likewise, the amount of artificial at night has increased by 10% in cities within the past decade.

Light and temperature also largely regulate plant growing seasons. For example, increased lighting and temperature cause trees in cities to bud and flower earlier in the spring and change color later in the autumn than trees in rural surroundings. However, research has not thoroughly studied the magnitude of their individual or combined impacts.