Khan Academy’s Marcia Lee Builds Tools for Online Education

Marcia Lee shapes the Khan Academy’s tools for Web-based instruction

3 min read
Marcia Lee

Despite being photographed outdoors in full sunlight, a 160-mm-diagonal, color cholesteric liquid-crystal display, built with off-the-shelf electronics for demonstration purposes by Kent Displays Inc., shows a bright image. The image is produced by reflected light, not backlighting, and no power is needed to hold the image on the screen.

Photo: Gabriela Hasbun; Stylist: Tietjen Fischer


In late August 2010, Marcia Lee, newly graduated from Stanford with a master's degree in computer science, packed her car and drove north from Silicon Valley for what she thought would be a fantastic job at Microsoft and an awesome apartment in Seattle. She turned out to be right about the digs but wrong about the work.

So after just five months, Lee quit Microsoft and headed back to Silicon Valley. The apartment she settled into there was nothing special, but the new job she found, at the Khan Academy, sang to her heart.

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A Diamond "Blanket" Can Cool the Transistors Needed for 6G

Gallium nitride transistors have struggled to handle the thermal load of high-frequency electronics

4 min read
blue mountain of crystals with an inset of molecules on a pink background
Sarbanti Chowdhury/Stanford

High-power radio-frequency electronics are a hot commodity, both figuratively and literally. The transistors needed to amplify 5G and future 6G signals are struggling to handle the thermal load, causing a bottleneck in development. Engineers in the United States and England have teamed up to demonstrate a promising solution—swaddling individual transistors in a blanket of thermally conductive diamond to keep them cool.

“Thermal issues are currently one of the biggest bottlenecks that are plaguing any kind of microelectronics,” says team lead Srabanti Chowdhury, professor of electrical engineering at Stanford University. “We asked ourselves ‘can we perform device cooling at the very material level without paying a penalty in electrical performance?’”

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New Contactless ECG Continuously Monitors the Heart

Millimeter-wave radar device make electrode-less cardiovascular health tech possible

3 min read
Video still of a man lying down. A box shaped device on a pole sits above his body. To the left, a monitor displays ECG readings.

The researchers demonstrated an experimental setup for contactless ECG monitoring using millimeter-wave radar.

University of Science and Technology Of China/IEEE

This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.

More than 100 years after the technology was first developed, the electrocardiogram (ECG) remains the gold standard for measuring the electrical activity of the heart. However, an ECG currently requires electrodes to be attached on a person’s skin. Even the latest consumer technologies like the Apple Watch require a user seeking an ECG to touch a finger to the device’s protruding “digital crown,” forming a circuit across the user’s body, thereby enabling electrical signals across the heart to be measured.

However, researchers in China have reported the invention of a novel ECG technology that uses millimeter-wave radar and AI to infer an ECG signal, making the system completely contactless. Should the researchers’ initial promising results bear out, the millimeter-wave tech could inspire new applications based on a reliable and uninterrupted stream of heart health data.

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Get the Coursera Campus Skills Report 2022

Download the report to learn which job skills students need to build high-growth careers

1 min read

Get comprehensive insights into higher education skill trends based on data from 3.8M registered learners on Coursera, and learn clear steps you can take to ensure your institution's engineering curriculum is aligned with the needs of the current and future job market. Download the report now!