【推荐1】Israeli researchers say they have invented a reusable face mask that can kill the coronavirus with heat by drawing power from a mobile phone charger.

The disinfecting (消毒) process takes about half an hour—and users should not wear the mask while it is plugged in, said Professor Yair Ein-Eli, who led the research team at Technion University in Haifa. The new mask has a USB port that connects to a power source such as a standard cell-phone charger that heats an inner layer of carbon fibres to 70 degrees Celsius, high enough to kill viruses.

Ein-Eli said disposable masks were not economically or environmentally friendly. “You have to make it reusable and friendly, and this is our solution,” he said.

Professor Allon Moses, an infectious diseases expert at Jerusalem’s Hadassah Medical Center, said there was “no question” that a half hour’s exposure to 70-degrce heat would kill the coronavirus. But he cautioned that repeated heating could “damage the mask’s paper or fabric and spoil its ability to protect from diseases in the future”.

During testing, the prototype was exposed to 20 heating cycles, each for half an hour, with no impact on durability, Ein-Eli said. “We can guarantee it up to a few dozen cycles, without any risk,” he added.

The prototypc looks like a standard N95 face mask, with a valve (阀) at the front and bands to hold it in place around the head. The researchers submitted (递交) a patent for the mask in the United States in late March and say they are discussing commercializing the product with the private sector.

【推荐2】It is becoming more and more important for researchers to closely observe our sea life, with climate change and overfishing damaging our oceans. However, this is almost impossible since human presence scares the animals. Now, thanks to The Soft Robotic Fish, also called SoFi, researchers may not only be able to keep a close eye on the creatures, but also uncover undersea secrets that have been confusing us for centuries.

Built by MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL), the snow-white remote-controlled robot closely emulates real fish, complete with a flexible tail and two "fins". Though not the first autonomous underwater vehicle (AUV) created to observe the oceans, SoFi solves many of the issues that have hindered (妨碍)the usefulness of previous robots.

AUVs traditionally have had to be tied to a boat because radio frequency communications do not work well underwater. To solve the problem, CSAIL director Daniela Rus and her team used sound waves which can travel greater distances, allowing drivers using a waterproofed Super Nintendo controller to pilot SoFi from up to 50 feet away. To ensure SoFi can freely move around the ocean, a pump moves water from one balloon-like structure to the other through its soft rubber tail, while a controller fitted with a battery powers the robot through the ocean, unhindered by propellers (螺旋桨).

During test dives in Fiji's Rainbow Reef, SoFi moved alongside the sea life at depths of 50 feet for up to 40 minutes at a time, taking high-resolution photos and videos. Even more importantly, it was able to do so without causing any disturbance. The researchers say sometimes the fish would swim alongside the strange-looking robo- fish out of curiosity, while at other times they appeared completely unaware of its existence.

While SoFi currently only records videos, future versions will include sensors. "For us, this fish is magical," says Rus. “We imagine someday it might help us uncover more mysteries from the amazing underwater world that we know so little about."

【推荐3】Tech giants Apple and Google are teaming up to create a system that would let smartphone users know when they’ve come into contact with someone who has COVID-19.

The technology would rely on the Bluetooth signals that smartphones can both send out and receive. If a person tests positive for COVID-19, they could inform public health authorities through an app. Those public health apps would then warn anyone whose smartphones had come near the infected person’s phone within 14 days.

The technology could be used on both Google Android phones and Apple iPhones. The companies insist that they will preserve smartphone users’ privacy. Smartphone users must choose to use it independently. The software will not collect data on users’ physical locations or their personally identifiable information. People who test positive would remain anonymous(匿名的), both to the people who came in contact with them and to Apple and Google.

The American Civil Liberties Union (ACLU) has warned that using cellphone data to address the pandemic(流行病) may carry risks of “invasions of privacy, abuse of information, and stigmatization(污名化)”.

An adviser from ACLU, Jennifer Granick said that the joint Apple and Google project “appears to mitigate the worst privacy and concentration risks, but there is still room for improvement.” She added that contact tracking apps should be “voluntary and used only for public health purposes and only for the period of this pandemic.”

Google and Apple say their technology will be used only by public health authorities to track the spread of COVID-19.

A team at MIT also has been working on a contact-tracking system that similarly uses Bluetooth signals to identify when people have come near each other.

Apple and Google are carrying out their contact-tracking technology in two steps. In mid-May, they will release(发布) software that will let public health authorities build apps that exchange information via Bluetooth. In the coming months, they will update their operating systems so phones can share information without having to install an app.

【推荐1】Global waming is the increase of the earth’ s average surface temperature due to the effect of greenhouse gases, for example, carbon dioxide, which traps heat that would otherwise escape from the earth. After the trees are cut down and more greenhouse gases are released, the “blanket’around the earth called the ozone layer(臭氧层), will get thicker. This catches more heat and makes the earth hotter. Luckily, there are many things that every citizen of the earth can do to help reduce the effects of global warming, and it is never too late or too early for children to take action.

The children should learn what a carbon footprint is. A carbon footprint is the amount of carbonand greenhouse gases people make as they lead the daily life and go about the normal activities. In other words, the carbon footprint is a measure of the environmental impact(冲击)the life has. To live an environmentally friendly life that doesn’t contribute to global warming, people want to have the smallest carbon footprint possible.

Almost everything people do contributes to global warming and is related to fossil fuel consumption. These can be direct uses of fossil fuels, like riding in a gasoline-powered car, or indirect contributions to greenhouse gases, such as eating fruits or vegetables that have to be shipped from far away to reach their tables.

If a child wants to make a contribution to reducing global warming, he should ridc a bicycle tothe near park, school, his friend’s house, or anywhere else instead of taking the car. Or he may try to walk or jog, which is also helpful. In addition, although trains and buses often run on fossil fuels, on average, each person uses less energy and produces less polution to run. Next time if children with their parents have to get around town or it’s too far to walk or bike, take the bus or other public transportation instead of asking for a ride.

【推荐2】Heavy traffic doesn’t stop big mammals like bears from crossing highways — nor does it keep smaller creatures from being squished (压扁) by cars. In just two years along one highway in Utah, more than 100 animals were killed in traffic accidents. In the United States, there are 21 endangered species whose survival is threatened by traffic accidents.

However, there’s one way to reduce crashes between cars and animals crossing the road: wildlife under and overpasses. Looking much like a regular overpass for cars, but decorated with native plants, they aren’t particularly noticeable unless you know what you’re looking for. The drivers may not be able to see the under crossings. But they’re helping countless species to pass the highways, from gold monkeys in Brazil to water voles in London.

Washington State is one of the latest to join in. Building its first wildlife bridge began in 2015 over Interstate 90 (I-90), which runs from Seattle to Boston. Though it’s just a bare set of arches now, with native plants to be planted next year, deer and wolves are already using it. Along with six underpasses built since 2013, these crossings are the first in a set of 20 along a 15-mile stretch of highway on I-90. These passes will allow black bears and mountain lions to pass through what was once an impenetrable road.

These wildlife crossings aren’t just about saving individual animals — they’re about species survival, too. I-90 is an economically important east-west lifeline in the state. But many of the animals mostly want to move from north to south. Those animals on the south of the highway got trapped in an island. Inbreeding (近亲繁殖) became a potential problem. Localized extinction happens if they don’t have genetic variability. The Snoqualmie overpass helps reconnect these isolated (隔绝的) populations. I-90’s underpasses are important in connecting waterways and species.

【推荐3】Too many people want others to be their friends, but they don’t give friendship back. That is why some friendships don’t last very long. To have a friend, you must learn to be one. You must learn to treat your friend the way you want your friend to treat you. Learning to be a good friend means learning three rules: be honest; be generous; be   understanding.

Honesty is where a good friendship starts. Friends must be able to trust one another. If you don’t tell the truth, people usually find out. If a friend finds out that you haven’t been honest, you may lose your friend’s trust. Good friends always rely on one another to speak and act honestly.

Generosity means sharing and makes a friendship grow. Naturally you will want to share your ideas and feelings. These can be very valuable to friends. They tell your friends what is important to you. By sharing then you help your friend know you better.

Sooner or later everyone needs understanding and help with problems. Something may go wrong at school. Talking about the problem can make it easier to solve. Turning to a friend can be a first step in solving the problem. So to be a friend you must listen and understand. You must try to put yourself in your friend’s place so you can understand the problem better.

No two friendships are ever exactly alike. But all true friendships have three things in common. If you plan to keep your friends, you must practice honesty, generosity and understanding.