The 2014 Nobel Prize in physics went to three scientists who gave lighting a big change by inventing blue LED lights. A big change in lighting efficiency is under way around the world.
Save and green
LEDs use less energy than other forms of lighting. A typical LED bulb(灯泡) can produce around 83 lumens per watt — a measure of how much brightness you can get from a unit of electrical power — much more efficient than other lighting facilities.
LEDs produce light by passing electric current through a semiconductor, while traditional bulbs pass current through a wire. The wasted heat energy is chiefly why traditional bulbs are so much less efficient.
LEDs also last about 30 times longer than traditional bulbs, and many LED bulb products promise up to 25,000 hours of use — more than 17 years if you used one for about four hours a day.
Lighting the world
The lighting application is not only in homes. LEDs are also being used for street lights, public holiday and decorative displays, commercial buildings, and other large energy users.
Car lighting is another application where LEDs are making progress. LEDs used to be used only for daytime running lights, but now many new cars have LED headlights for night-time use.
LEDs also hold promise for bringing light to the more than 1.5 billion people around the world without access to electricity, the Royal Swedish Academy of Sciences noted. Indeed, several proposed solutions to energy poverty include the distribution of LED lights, particularly solar-powered ones.
Digital displays
Without blue LEDs, the world wouldn’t have back-lit smart phones, TV and computer LCD screens, blu-ray(蓝光) players, many forms of lighting, and countless other products.
In the electronics industry, LEDs provide back lighting for the liquid crystal displays (LCDs) in many smart phones, laptops, and televisions. The LEDs are more energy efficient and allow for very thin displays.
Blu-ray players use blue LED lasers(激光) to read data off a digital optical disc. When these systems switched from using an infrared(红外线) laser to a blue LED laser, it became possible to store five to 10 times as much data.
LEDs are now being explored for their potential to transmit(传送) data from the Internet across open space, similar to WiFi. Such a system could transmit a lot more data than WiFi alone. This high bandwidth is possible because LEDs can turn on and off millions of times per second.
The rise of LED lighting came at a time when people were just starting to be concerned about global warming. Because of LEDs’ energy efficiency, using them for the world’s lighting would have “an extreme impact” on society.
I___________ for Blue LED Lights to win the 2014 Nobel Prize in physics
●They_______ big changes in lighting.
II________ of LEDs
●Save and green
1. Compared with other forms of lighting, LEDs are much more efficient because of the different_________ they pass electric current
2. LED bulbs can be used 30 times longer than traditional bulbs.
●Lighting the world
1. Besides_ ___________ of LED bulbs they can also be used as street lights and car headlights.
2. Because of their high efficiency, LEDs, especially solar-powered ones, promising to light areas____________ electricity.
●Digital displays
1. Many smart phones, laptops and televisions use LEDs to back-light their LCD_________.
2. By using blue LED lasers, blu-ray players are likely to___________.
3. People are now exploring more_________ uses of LEDs such as transmitting data.
III Conclusion
LED lighting will_________ on environmental protection.
Sam is an in-real-life streamer(播主),and he live streams himself just going about his day.While riding his bike home 14 a cold night,he came across a sad-looking elderly woman wandering the streets by herself.The poor woman wasn't able to give him any information about 15 she lived.Sam walked her to a nearby convenience store so that she could 16 (safe) wait for the police to take her home.
Why do we dream?Scientists aren't completely sure,and they have diverse 11 (idea).Dreams might be a side effect of memory making.When you sleep,your brain sorts through everything 12 happened during the day,trying to link new experiences to old memories. As it 13 (connect) things,your brain tums them into a story,and you get a dream.
A comprehensive study of 4,500 children conducted by the National Institutes of Health in 2018 shows that children who spent more than seven hours a day staring at screens showed evidence of premature thinning of their brain's cortex the outer layer that processes sensory information. "We don't know if it (1) (cause) by the screen time. We don't know yet if it's a bad thing. It won't be until we follow them over time (2) we will see if there are outcomes that are associated with the differences that we're seeing in this single snapshot," Dr. Gaya Dowling. "What we can say is that this is(3) the brains look like of kids who spend a lot of time on screens. And it's not just one pattern."
The problem isn't just screens (4) , but also the way screens tempt kids (and adults) away from something far more important: physical activity. More than 23 percent of adults and 80 percent of adolescents don't get enough physical activity, and according to a 2019 report from the World Health Organization (WHO), these patterns of activity and rest arise (5) habits we develop early in life. "What we really need to do is (6) (bring) back play for children," says Dr. Juana Willumsen, a WHO specialist in childhood obesity and physical activity, in a statement about new WHO guidelines issued in April 2019. "This is about making the shift from sedentary time to playtime, while (7) (protect) sleep." Of course, children aren't completely to blame for their screen addiction.
Sometimes, the parents (8) complain about the role of screens in family life are just as guilty of spending too much time in front of one. A 2016 study (9) (conduct) by Common Sense Media found that parents spend up to nine hours a day in front of screens, mostly not for work﹣related reasons. While 78 percent of parents said they believed they were good screen time role models, the study found a disconnect between their behavior and their perception of their behavior. Parents need to limit screen time for themselves and especially for their kids(10) it means playing the bad guy. Our mental and physical health depends on it.
In the presence of animals
A professor of public health at UCLA says that pet ownership might provide a new form of health care. As far back as the 1790s, the elderly at a senior citizens' home in England (1)
(encourage) to spend time with farm animals. This would help patients' mental state more than the cruel therapies(2) (use) on the mentally ill at the time. In recent years, scientists have finally begun to find proof(3) contact with animals can increase a sick person's chance of survival and have shown (4) (lower) heart rate, calm upset children, and get people to start a conversation.
Scientists think that animals' companionship is beneficial (5) animals are accepting and attentive, and they don't criticize or give orders. Animals have the unique ability to be more social. For example, visitors to nursing homes get more social responses from patients when they come with animal companions.
Not only do people seem (6) (anxious) when animals are nearby, but they may also live longer. Studies show that a year (7) heart surgery, survival rates for heart patients were higher for those with pets in their homes than those without pets. Elderly people with pets make fewer trips to doctors than those without animal companions, possibly because animals relieve loneliness. Staying with animals is believed to create a peaceful state of mind,(8) (result) in a favorable environment for everyone.
Research confirms that the findings concerning senior citizens can be applied to restless children. They are more easy﹣going when there are animals around, with (9) company they tend to calm down more easily. They involve (10) in playing with animals and the presence of animals conforms them greatly.
I'm not sure(1) is more frightened, me or the female gorilla(大猩猩)that suddenly appears out of nowhere. I' m walking on a path in the forest in the Central African Republic. Unexpectedly, I'm face﹣to﹣face with the gorilla, who begins screaming at(2) top of her lungs. That makes her baby scream, and then a 400﹣pound male appears.He screams the (3) (loud )of all. The noise shakes the trees as the male beats his chest and charges toward me. I quickly lower myself, ducking my head to avoid (4) (look)directly into his eyes so he doesn't feel (5) (challenge).
My name is Mireya Mayor. I'm a (6) (science)who studies animals such as apes and monkeys. I was searching(7) these three western lowland gorillas I'd been observing. No one had seen them for hours, and my colleagues and I were worried.
When the gorillas and I frightened each other, I was just glad to find (8) (they)alive.True to gorilla′s unaggressive nature, the huge animal(9) (mean)no real harm.He was just saying: " I'm king of this forest, and here is your reminder! "Once his message was delivered, he allowed me (10) (stay)and watch.