Pandemic is pushing women in STEM ‘past the point of no return’

Cryocoolers are ultracold refrigeration units used in surgery and drug development, semiconductor fabrication, and spacecraft. The regenerative heat exchanger, or regenerator, is a core component of cryocoolers. At temperatures below 10 kelvins, performance drops precipitously, with maximum regenerator loss of more than 50%. In Applied Physics Letters, researchers used superactivated carbon particles as an alternative regenerator material to increase cooling capability at temperatures as low as 4 kelvins.

Thermal Power Nanogenerator Created Without Solid Moving Parts

As environmental and energy crises become more common, a thermal energy harvester capable of converting abundant thermal energy into mechanical energy appears to be a promising mitigation strategy. The majority of thermal power generation technologies involve solid moving parts, which can reduce reliability and lead to frequent maintenance. This inspired researchers in China to develop a thermal power nanogenerator without solid moving parts. In Applied Physics Letters, they propose a thermal power nanogenerator that converts thermal energy into electrical energy.

Enhanced Ceramics Could Play Pivotal Role in Advancing 5G Technology

Michael Hill, technical director of Skyworks Solutions, and his colleagues provide an overview in Applied Physics Letters on nascent 5G technologies and show how enhancing ceramic materials could play a pivotal role in development. They have developed a ceramic called a circulator, a three-port device that serves as a traffic circle to keep the signal flowing in one direction and enable a receiver and a transmitter to share the same antenna.

Singing a Tumor Test Song

Singing may be the next-generation, noninvasive approach to determining the health of a patient’s thyroid. When a person sings, the vibrations create waves in the tissue near the vocal tract called shear waves. If a tumor is present in the thyroid, the elasticity of its surrounding tissue increases, stiffening, and causing the shear waves to accelerate. Using ultrasound imaging to measure these waves, researchers can determine the elasticity of the thyroid tissue. They demonstrate the technique in Applied Physics Letters.

Wearable Electronics for Continuous Cardiac, Respiratory Monitoring

A small and inexpensive sensor, announced in Applied Physics Letters and based on an electrochemical system, could potentially be worn continuously by cardiac patients or others who require constant monitoring. A solution containing electrolyte substances is placed into a small circular cavity that is capped with a thin flexible diaphragm, allowing detection of subtle movements when placed on a patient’s chest. The authors suggest their sensor could be used for diagnosis of respiratory diseases.

Decorating Windows for Optimal Sound Transmission

Glass windows typically offer some amount of sound proofing, sometimes unintentionally. In general, ventilation is required to achieve large sound transmission. But some applications — like gas explosion studies — require a transparent partition that allows for acoustic propagation without the presence of airflow. In those cases, ventilation is not allowed. In Applied Physics Letters, researchers discuss a layered glass material they developed that allows for efficient sound transmission with no air ventilation.

Cooling Mechanism Increases Solar Energy Harvesting for Self-Powered Outdoor Sensors

Thermoelectric devices, which use the temperature difference between the top and bottom of the device to generate power, offer some promise for harnessing naturally occurring energy. In Applied Physics Letters, authors tested a device made up of a wavelength-selective emitter that constantly cools the device during the day using radiative cooling. As a result, the top of the device is cooler than the bottom, causing a temperature difference that creates constant voltage through day and night and various weather conditions.

Atomic Magnetometer Points to Better Picture of Heart Conductivity

Mapping the electrical conductivity of the heart would be a valuable tool in diagnosis and disease management, but doing so would require invasive procedures, which aren’t capable of directly mapping dielectric properties. Significant advances have recently been made that leverage atomic magnetometers to provide a direct picture of electric conductivity of biological tissues, and in Applied Physics Letters, new work in quantum sensors points to ways such technology could be used to examine the heart.

Extreme High-Frequency Signals Enable Terabits-Per-Second Data Links

Using the same technology that allows high-frequency signals to travel on regular phone lines, researchers tested sending extremely high-frequency, 200 GHz signals through a pair of copper wires. The result is a link that can move data at rates of terabits per second, significantly faster than currently available channels. In Applied Physics Letters, the scientists discuss their work using experimental measurements and mathematical modeling to characterize the input and output signals in a waveguide.

Recipe for Neuromorphic Processing Systems?

The field of “brain-mimicking” neuromorphic electronics shows great potential for basic research and commercial applications, and researchers in Germany and Switzerland recently explored the possibility of reproducing the physics of real neural circuits by using the physics of silicon. In Applied Physics Letters, they present their work to understand neural processing systems, as well as a recipe to reproduce these computing principles in mixed signal analog/digital electronics and novel materials.

Robotic Gripping Mechanism Mimics How Sea Anemones Catch Prey

Researchers in China demonstrated a robotic gripping mechanism that mimics how a sea anemone catches its prey. The bionic torus captures and releases objects by crimping its skin. The grasper not only is relatively cheap and easy to produce but also can grab a variety of objects of different sizes, shapes, weights and materials. They discuss their work in this week’s Applied Physics Letters.

Ultrasound Selectively Damages Cancer Cells When Tuned to Correct Frequencies

Doctors have used focused ultrasound to destroy tumors without invasive surgery for some time. However, the therapeutic ultrasound used in clinics today indiscriminately damages cancer and healthy cells alike. Researchers have now developed a low-intensity ultrasound approach that exploits the properties of tumor cells to target them and provide a safer option. Their findings, reported in Applied Physics Letters, are a new step in oncotripsy, the singling out and killing of cancer cells based on their physical properties.