Mechanical Engineering: Research Guide

Researchers at Nagoya University have built a graphene nanoribbon that can switch the direction of its twist using a natural solvent. Graphene nanoribbons are thin, ribbon-shaped structures made of fused carbon rings. Twisted or helical versions of these ribbons show promise for advanced light and electronic devices. However, until now, no graphene nanoribbon could switch its twist on demand.

A team of Korean researchers has become the first in the world to identify the origin of the "beating" signal that has long been a major obstacle to interpreting quantum signals in topological insulator (TI) nanowires. Their analysis confirmed that the beating arises when two different quantum oscillations overlap: one created by topological electronic states on the surface and the other by ordinary electronic states inside the nanowire. This achievement provides a key criterion for interpreting the signals of topological quantum devices and realizing desired electronic states.

For children born with cleft lip and palate, repairing gaps in the jawbone often means waiting until they are 10 to 12 years old before undergoing invasive bone graft surgery. University of Sydney researchers have developed a biodegradable "nanobone" material that allows the body to harness its own healing properties to regrow bone, offering a potential future alternative to procedures that have changed little in more than 50 years.

Imagine a construction site where the bricks are individual molecules and the "cranes" are microscopic needles so sharp they can feel a single atom. For decades, building at this scale was a laborious, time-consuming task where a single human error could damage the delicate tools.

Researchers from Graz University of Technology (TU Graz), Harvard and the University of Texas at Austin (UT Austin) have developed an innovative method for coupling light non-linearly. This opens up new possibilities for telecommunications and quantum technology.

One of the major challenges in the quest to beat cancer is developing treatments that can selectively destroy cancer cells while leaving healthy cells unharmed. With this in mind, researchers at the Indian Institute of Technology Gandhinagar (IITGN) have devised a gold nanorod-based platform that delivers therapeutic agents specifically to the endoplasmic reticulum (ER), a structure responsible for protein production and processing within cells, while also generating heat when exposed to near-infrared light.

Advanced materials power everything from batteries and electronics to clean energy technologies. For years, engineers have known that microwave-assisted synthesis can dramatically accelerate the chemical reactions used to manufacture these materials. Now, researchers at Carnegie Mellon University have provided new evidence challenging a long-held assumption about why, suggesting that microwaves speed chemical reactions in a fundamentally different way than many scientists believed.

While fridge magnets are great for saving favorite recipes, modern magnetic materials are useful for improving fiber optics or quantum information science technology. On most fridge magnets the atoms are arranged in a repeated lattice structure called a "spinel." These structures are made up of three types of atoms, generically referred to as atoms "A," "B" and "X."

A collaborative research team has successfully visualized in real space the ultrafast optical modulation of hyperbolic phonon polaritons (HPhPs) in a van der Waals heterostructure composed of hBN and WS2. The research is published in the journal Nano Letters, and was led by Kazuki Kamada of the Institute for Molecular Science (IMS) and Osaka Metropolitan University, along with Dr. Jun Nishida, assistant professor at IMS, and Takashi Kumagai, associate professor at IMS.

A new way to imprint complex surfaces on low-cost, sustainable polymers could be used in a wide range of industries, including water-repellent coatings, optical devices and data storage disks. The complex nano- and microscale patterns on sulfur-derived polymers, unveiled this week in the ACS Applied Materials and Interfaces journal, build on a wide range of green chemistry solutions led by Flinders University.

Czech researchers at Charles University in Prague, led by Pavla Eliášová, have developed an advanced photocathode that helps convert the greenhouse gas carbon dioxide into pure ethanol using sunlight. The new technology solves a long-standing problem of material degradation in water, achieves record conversion efficiency and opens the way toward sustainable production of green fuels. The paper is published in the journal Advanced Energy Materials.

Graphene is an exceptionally useful material for creating batteries, catalysts and electronic devices. Yet producing graphene typically requires temperatures as high as 900°C (1,652°F), limiting energy efficiency and making structural control difficult. To make graphene production more practical, a recent study has overcome this long-standing temperature barrier.

A research team led by Sungwon Lee, a professor in the Department of Physics and Chemistry at DGIST, developed a hierarchical nano-on-nano structure by directly growing graphene nanowalls (GNWs) on polymer nanofibers and successfully used the structure to enhance the sensing performance of wearable gas sensors. The technology is expected to be applied to next-generation wearable sensors for real-time monitoring of individuals' breathing environments or hazardous gases in industrial settings.

Researchers at Delft University of Technology have demonstrated for the first time that nano-antennas can enhance the fluorescence of proteins in living human and other mammalian cells. Scientists already use smart fluorescent proteins that light up when the electrical voltage across a nerve cell changes. By placing nano-antennas close to these light-emitting proteins, researchers can monitor processes inside cells with much greater precision. The discovery adds a new tool for revealing electrical signals in the brain through nanotechnology as well as genetic engineering. The research has been published in Advanced Materials.

Researchers have captured in real time the "birth moment" when the performance of a next-generation memory material is determined. The key lies in controlling oxygen vacancies, microscopic defects created when oxygen atoms are missing from their normal positions.

Plastic pollution is one of the most urgent environmental challenges of the 21st century. As larger plastic debris breaks down through mechanical, photochemical and biological processes, it forms microplastics that have been detected in water, soil, air and even the human body. Among these materials, polyamide microplastics are of particular concern because polyamide is widely used in textiles, fishing gear, packaging and engineering materials.

Some molecules come in two "handed" forms. This property, called chirality, can influence not only how molecules interact with light but also which electron spins they allow to pass. Researchers at the University of Osaka have developed novel chiral hole-transport materials that shed new light on this unusual effect while also improving the interfaces of perovskite solar cells.

A new manufacturing method could help move the production of nanoscale sensors from specialized fabrication facilities to conventional semiconductor manufacturing plants.Publishing in Science Advances, researchers from KTH Royal Institute of Technology liken their technique to uprooting a tree stump with a rope.

What does a clean room smell like? Many people say citrus, pine, or flowers because these fragrances are common in cleaning products. A research team led by Brandon Boor found that scent compounds in cleaning products—conventional and botanical essential oil-based—quickly react in the air, forming nanoparticles that can travel deep into the lungs if inhaled. To reduce exposure to this invisible pollution, the team suggests using unscented products, running exhaust fans, and avoiding ozone-generating devices while cleaning.

Researchers at Queen Mary University of London have shown that making extremely small changes to the structure of a material can dramatically improve its ability to respond to electrical signals. Published recently in Science Advances, the breakthrough could help create a new generation of wireless devices that can change frequency on demand, making communication systems more flexible and energy efficient.

The next time you need to freshen up the paint on your house or apply a bit of cosmetic glitter before heading out for the night, you might want to give a quick nod to the butterflies fluttering in a nearby garden. Taking inspiration from structures on those wings that create their vibrant colors, researchers are now devising more durable and adjustable colors that are also safer for human health and the environment.

In micro- and nanotechnology, highly precise components with tall, narrow structures (high aspect ratios) made from semiconductor materials like silicon are important. A promising fabrication method is gas-phase metal-assisted chemical etching (MacEtch). In this plasma-free process, a thin metal layer defines the pattern on the silicon substrate. The etching step takes place in a chemical environment, where the reaction occurs only at the interface between the metal and silicon. The metal catalyst gradually sinks into the silicon, directing the etching deeper.

Researchers from Skoltech and their colleagues from Harbin Institute of Technology in China and ITMO University in Russia have devised a way to deposit elaborate geometric patterns of carbon nanotubes without wasting material. Such patterns are used in advanced optical devices and mechanical strain sensors for structural integrity monitoring.

There is something slightly ridiculous about using a kitchen blender to make graphene. This is, after all, the "wonder material" associated with futuristic technologies. You might reasonably expect its production to involve equally futuristic equipment. Often, it does.

You may have once tried taking a close-up picture of a computer screen and noticed a wavy, rippling effect. This optical effect occurs whenever two fine, repeating grids overlap and slightly misalign, such as when the pixel grid of your camera's sensor overlaps with the pixel grid of the screen.

Biomolecular nanomachines, such as enzymes and molecular motors, are the workhorses behind the synthesis and organization of complex materials in life. Powered by chemical energy, they build, transport and organize biomolecules, allowing living systems to create and maintain highly ordered structures far from thermodynamic equilibrium.

Quantum dots are semiconductor crystals only a few nanometers in size. Their ability to produce bright, precisely tunable colors has made them promising materials for light-emitting diodes, displays, solar cells and other optoelectronic technologies. Yet heat remains a major obstacle to their practical use.

AR and VR glasses once seen only in science fiction may soon be realized not as bulky stacks of lenses but as a single eyeglass-like optical element. That future is now closer to reality.

Self-assembling, anthracene-based supramolecular nanofibers can enable excitons to migrate hundreds of nanometers, according to a new experimental finding by researchers at Science Tokyo. Coupling these nanofibers with a plasmonic gold nanohole substrate further doubles exciton diffusivity. By mitigating the limited diffusivity of singlet excitons in organic semiconductors, this approach offers a new strategy for improving optoelectronic technologies.

Bubbles are round, and we know surface tension does that. But squeeze that gas-liquid boundary into a space only a few tens of nanometers wide—could other forces be at work?