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Category: nanotechnology – Page 108

Researchers have developed a proof of concept technology that could pave the way for next-generation displays beyond current LCDs and LEDs, enabling screens and electronic devices to become thinner, offer higher resolution and be much more energy efficient.

A team at Nottingham Trent University, the Australian National University and the University of New South Wales Canberra in Australia has engineered electrically tunable arrays of nanoparticles called “metasurfaces,” which can offer significant benefits over current liquid crystal displays.

Today’s display market offers a large range of choices, each with its pros and cons. However factors including production costs, lifespan and energy consumption have kept liquid crystal technology the most dominant and popular technology for screens such as TV sets and monitors.

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In a new study, researchers at the Indian Institute of Science (IISc) show how a brain-inspired image sensor can go beyond the diffraction limit of light to detect miniscule objects such as cellular components or nanoparticles invisible to current microscopes. Their novel technique, which combines optical microscopy with a neuromorphic camera and machine learning algorithms, presents a major step forward in pinpointing objects smaller than 50 nanometers in size. The results are published in Nature Nanotechnology.

Since the invention of optical microscopes, scientists have strived to surpass a barrier called the , which means that the microscope cannot distinguish between two objects if they are smaller than a certain size (typically 200–300 nanometers).

Their efforts have largely focused on either modifying the molecules being imaged, or developing better illumination strategies—some of which led to the 2014 Nobel Prize in Chemistry. “But very few have actually tried to use the detector itself to try and surpass this detection limit,” says Deepak Nair, Associate Professor at the Center for Neuroscience (CNS), IISc, and corresponding author of the study.

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A research team from LKS Faculty of Medicine, the University of Hong Kong (HKUMed) has developed thyroid hormone (TH)–encapsulated nanoparticles modified with an adipose-homing peptide, which selectively transports TH to adipose tissues. This will advance the treatment of obesity-related medical complications with TH by overcoming the severe adverse effects caused by systemic administration. The new findings are now published in Nature Communications.

Obesity is a major risk factor for multiple life-threatening such as diabetes and cardiovascular and neurodegenerative disorders. TH is an ancient hormone with therapeutic potential for obesity and its related medical complications by promoting energy expenditure. However, despite enormous research efforts in the past decades, have failed to demonstrate obvious clinical benefits of chronic systemic administration of TH on in obese individuals.

Furthermore, due to widespread expression of TH receptors, systemic administration of TH often leads to serious deleterious effects on multiple organs, including tachycardia, , muscle wasting, and osteoporosis. Skeletal muscle and adipose tissues are thought to be the two major target organs where TH exerts its stimulatory actions on metabolic rate and energy expenditure. However, whether selective delivery of TH to adipose tissues is sufficient to induce weight loss remains unclear.

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Professor Juhyuk Lee of the Department of Energy Engineering has developed an elastic triboelectric generator that can be used in the daily lives of frequent movers. The cause of the output reduction of the elastic triboelectric sensor was identified during joint research with Professor Joohun Lee of Hanyang University’s (ERICA campus) Department of Bio-Nanotechnology. Additionally, the professor used graphene to develop a touch sensor with stable output and expand the application of the triboelectric generator. The study is published in the journal Nano Energy.

Along with the rapid growth of various biosensors and due to the continuous development of semiconductors and small electronic components, there has been a growing interest in triboelectric generators for use as sensors or . To use the triboelectric generator in a wearable device, the material that comes into contact with the body must be safe, and the output must be constant despite any deformations caused by movement.

However, the output of conventional elastic triboelectric generators is affected by its change in form. The reason for this relationship was not clearly understood. Similar to previously existing products, there are limitations to precise detection if the output changes along with the change in form, such as stretching.

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A fuel cell is an electric power generator that is capable of producing electricity from hydrogen gas while discharging only water as a waste product. It is hoped that this highly efficient clean energy system will play a key role in the adoption of the hydrogen economy, replacing the combustion engines and batteries in automobiles and trucks, as well as power plants.

However, the cost of platinum, which can be up to ~30,000 USD per kg, has been a major limitation, making catalysts prohibitively expensive. The production methods of highly-performing catalysts have also been complicated and largely limited. Accordingly, the development of a facile and scalable production method for platinum-based fuel cell catalysts is an urgent challenge, together with enhancing catalytic performance and stability while using a minimum amount of platinum.

To tackle this issue, a research team led by Prof. Sung Yung-Eun and Prof. Hyeon Taeghwan at the Center for Nanoparticle Research (CNR) within the Institute for Basic Science (IBS), South Korea has discovered a novel method for the production of nanocatalysts.

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Putting that soda bottle or takeout container into the recycling bin is far from a guarantee it will be turned into something new. Scientists at Rice University are trying to address this problem by making the process profitable.

The amount of waste produced globally has doubled over the past two decades—and plastic production is expected to triple by 2050—with most of it ending up in landfills, incinerated or otherwise mismanaged, according to the Organization for Economic Cooperation and Development. Some estimates suggest only 5% is actually being recycled.

“Waste plastic is rarely recycled because it costs a lot of money to do all the washing, sorting and melting down of the plastics to turn it into a material that can be used by a factory,” said Kevin Wyss, a Rice graduate student and lead author on a study published in Advanced Materials that describes how he and colleagues in the lab of chemist James Tour used their flash Joule heating technique to turn plastic into valuable carbon nanotubes and hybrid nanomaterials.

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A research team led by Dr. Yong-hun Kim and Dr. Jeong-Dae Kwon has successfully developed the world’s first neuromorphic semiconductor device with high-density and high-reliability by developing a thin film of lithium-ion battery materials. They achieved this by producing ultra-thin lithium ions, a key material of lithium-ion batteries that have been in the spotlight recently, and combining it with two-dimensional nano-materials. The research team is from the Surface & Nano Materials Division at the Korea Institute of Materials Science (KIMS).

A neuromorphic device has synapses and neurons similar to the , which processes and memorizes information. The synaptic device receives signals from neurons and modulates the synaptic weight (connection strength) in various ways to simultaneously process and store information. In particular, the linearity and symmetry of synaptic weights enables various pattern recognition with low power.

Traditional methods for controlling synaptic weights use charge traps between interfaces of heterogeneous materials or oxygen ions. In this case, however, it is difficult to control the movement of ions in the desired direction according to the external electric field. The researchers solved this problem with an artificial intelligence semiconductor device with high density by developing a thin film process while maintaining the mobility of lithium ions according to the external electric field. The thin film—with a thickness of several tens of nanometers—enables fine pattern processing while controlling the thickness of the wafer scale.

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Vibrations are the main drivers of a mysterious process in which a liquid flow generates an electric current in the solid below it.

Liquid flowing over a conducting surface is known to produce electric currents, but the mechanism behind this effect has been unclear. New experiments with a single liquid drop dragged over a graphene surface demonstrate that viscous forces at the liquid–solid interface create vibrations, or phonons, in the graphene sheet that drag electrons in the direction of the flow [1]. The researchers verified this “phonon wind” interpretation by observing multiple liquids and by testing graphene surfaces with and without wrinkles. The results could lead to highly sensitive flow sensors or to devices that can harvest electricity from flows.

Researchers have found that water flowing over a material—in particular, carbon nanotubes or graphene—can generate electric currents in the solid. The effect appears in carbon materials because the surfaces are atomically flat and thus allow the liquid to flow largely unobstructed at the liquid–solid boundary, explains Alessandro Siria from the École Normale Supérieure in France. Several models have been proposed to explain the flow-induced currents, often involving charges within the liquid acting on the electrons in the solid. However, experimental uncertainties have prevented researchers from determining which model is best.

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Researchers at the University of North Carolina at Chapel Hill Department of Chemistry have engineered silicon nanowires that can convert sunlight into electricity by splitting water into oxygen and hydrogen gas, a greener alternative to fossil fuels.

Fifty years ago, scientists first demonstrated that liquid water can be split into oxygen and using electricity produced by illuminating a semiconductor electrode. Although hydrogen generated using is a promising form of clean energy, low efficiencies and have hindered the introduction of commercial solar-powered hydrogen plants.

An economic feasibility analysis suggests that using a slurry of electrodes made from nanoparticles instead of a rigid solar panel design could substantially lower costs, making solar-produced hydrogen competitive with fossil fuels. However, most existing particle-based light-activated catalysts, also referred to as photocatalysts, can absorb only , limiting their energy-conversion efficiency under solar illumination.

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Some researchers are driven by the quest to improve a specific product, like a battery or a semiconductor. Others are motivated by tackling questions faced by a given industry. Rob Macfarlane, MIT’s Paul M. Cook Associate Professor in Materials Science and Engineering, is driven by a more fundamental desire.

“I like to make things,” Macfarlane says. “I want to make materials that can be functional and useful, and I want to do so by figuring out the basic principles that go into making new structures at many different size ranges.” (Image: Adam Glanzman)

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