Many metals must be made into thin films before they can be used in technological products like electronics or fuel cells. “Stubborn” metals, however, are very difficult to turn into thin films because they require extremely high temperatures.

Typically, scientists make metal films using the technique that consists of making metals become gas at high temperatures and allowing a film to form on top of wafers (晶片). But this conventional method is very expensive, uses a lot of energy, and may also bé unsafe due to high temperatures. Now, the researchers from University of Minnesota have developed a way to make these metals become gas at significantly lower temperatures, fewer than 200 degrees instead of several thousands. By designing and adding organic ligands (有机配体) to these metals, the researchers were able to greatly increase the material vapor (蒸气) pressure, making them easier to become gas at lower temperatures. Not only is their new technique simpler, but it also makes higher quality materials.

“The ability to make new materials with ease and control is necessary to walk into a new era of energy economy,” said Bharat Jalan, the senior author of the study. “There is already a historical link between the innovation in science and the development of new technology. Millions of dollars go into making materials for various applications. Now, we’ve come up with a simpler and cheaper technology that makes better materials.”

These “stubborn” metals are used to make lots of products. “Bringing down the cost and complexity of these metals will play a large role in both industrial and research efforts,” said William Nunn, the paper’s first author. “Now that making these metals into thin films becomes easier, we want to see renewed interest in the more complex materials which contain these stubborn metals.”

The research is published in the Proceedings of the National Academy of Sciences (PNAS).

If nothing is done to stop rising sea levels, the homes of 200 million people could be underwater by the year 2100. That's according to a study published in the scientific magazine Nature Communications. The global sea level has been rising for more than a century, and more quickly over the last several decades. That's because climate change is melting glaciers (冰川）and ice sheets. Higher sea levels flood coastlines. If steps aren't taken to protect cities and towns, people could be forced to move inland.

One European country is especially vulnerable to flooding: the Netherlands. More than a quarter of the country already sits below sea level. But the Netherlands has developed tactics (策略）for dealing with water. For that reason, many experts believe that even though it's vulnerable to rising seas, the country is well-equipped to deal with them.

In the region that is now the Netherlands, people have been inventing ways to keep out water for at least 900 years. The country is famous for its dikes (堤坝），which are long walls that prevent flooding. But in recent years, experts there have developed new techniques that go far beyond dikes, some of which are high-tech.For example, the Maeslantkering is a massive storm-surge barrier that protects the city of Rotterdam from seawater. It's controlled by a supercomputer. It closes automatically when Rotterdam is threatened by floods.

Other projects look to nature for inspiration.The DakAkker is a farm located on top of an office building in Rotterdam. The building's roof holds rainwater to prevent runoff. Another example is the Floating Farm. Its designers wanted to make room for agriculture in a waterflooded city. More than 30 dairy cows live on the farm, which floats in Rotterdam's waterways.The farm generates (生产）its own energy using floating solar panels.

“It's not that our solutions are the best,” says Henk Ovink, who works on water issues for the Dutch government. “But we provide ideas for your country's solutions.”

In India, vendors (小贩) travel around with iron boxes full of hot coals which they use to iron clothes. Vinisha Umashankar noticed that six of these vendors were present in her town of Tiruvannamalai, when she was 12 years old. Concerned about the environmental effect of burning charcoal (木炭), the young lady went to work designing an innovative solution: a solar-powered ironing cart (小推车) attached to a bicycle. Now at age 15, her idea has turned into a real invention.

Umashankar became interested in science from a young age. At age eight, she learned of the climate crisis, which drove her to come up with a clean-energy solution to the ironing vendors in India. In 2019, the then-tween spent months researching college-level physics to learn about solar panels. She made a design for a bicycle car with solar panels to power a steam iron. Her design received recognition at the National Innovation Foundation, which assigned engineers to help her create the cart, known as the Iron-Max.

The cart stores sunshine in a battery for cloudy days. Five hours of sunshine provide enough energy for six hours of ironing. The bike also has a cellphone charging port so the vendor can earn extra income by charging for a charge. The Iron-Max is free from the matter and greenhouse gases released by the traditional coal carts.

The invention had entered several international competitions. Umashankar was one of 15 finalists at the first-ever Earthshot Prize. Although she did not win the prize, she was the youngest finalist in the “Clean Our Air” category. She also won last year’s Children’s Climate Prize.

With her invention, Umashankar made a powerful five-minute speech at COP26, the UN’s climate summit, which has been making headlines. Umashankar said in her speech, “You are deciding whether or not we will have a chance to live in a habitable world. You are deciding whether or not we are worth fighting for, worth supporting, and worth caring for.”