On a Saturday morning earlier this September, the world got its first look at the Strati. This electric vehicle is unlike any other currently on the road. It rolls on four wheels, but its body and chassis(底盘) weren't built in a factory. Instead, Strati's designers used a technology called 3-D printing. It created those parts of the car in one piece, from the ground up.

    “Compared to a typical vehicle on the road, the Strati definitely looks different,” says Greg Schroeder, a senior research engineer at the Center for Automotive Research in Ann Arbor, Mich. He did not work on the new car. His organization studies trends and changes in th e auto industry.

    It took 44 hours to print the new car at the International Manufacturing Technology Show in Chicago. Over the next few days, the car's designers installed additional parts. These included the car's engine, brakes and tires. Then, early on September 13, Jay Rogers climbed into the car, started its engine and drove the vehicle onto the street. Rogers helped found Local Motors. It's the Arizona-based company behind the Strati. Two weeks later, his team printed a second Strati, and just as fast, at a fair in New York City.

    Justin Fishkin, a local Motors official, sees the Strati as a window into the future. Today, car buyers are limited in their choice of a vehicle. They can order only what car companies have already designed. But in the future, he says, you may be able to design your own car online and then get it printed to order.

    Manufacturing experts say 3-D printing has begun to revolutionize how they make things. The technology has been around for decades. But these machines used to be so expensive that only large companies could afford them. In the last few years, though, that has changed. Many of the machines are now inexpensive enough for small companies—or even individuals —to own. Some local libraries make them available to the public. High Schools are beginning to use them in classrooms. Wide access to these printers means people can now design and print a wide variety of new things.

    The car's printer is a one-of-a-kind device.

    The technology behind the 3-D printer used in Chicago is an example of additive manufacturing. This proce ss builds solid objects, slice by slice, from the bottom up. (“Strati” means layers, in Italian.) A mechanical arm moves a nozzle from one side to another, back and forth. As it moves, the nozzle deposits a liquid—often melted plastic or metal (but it could be food, concrete or even cells) —that quickly hardens or bonds to become solid or semi-solid. This creates a single, thin layer. Once a layer is complete, the printer starts depositing the next one.

     “There's a lot of interest in 3-D printing in the auto industry,” says Schroeder. Right now, the technology is particularly useful for building models of cars or car parts.

    To compete with current auto manufacturers, the 3-D printer would have to increase in a hurry, Schroeder says. By contrast, he notes, a Ford F-150 pickup truck rolls off an assembly line at a rate of roughly one per minute. To print as many Stratis would require many more printers. Schroeder says he doesn't see 3-D printing soon taking over for such high-volume manufacturing. But, he adds, “Who knows what will h appen in the long term?”

    Scientists at Oak Ridge National Laboratory in Tennessee designed the 3-D printer used in Chicago. Lonnie Love, a research scientist at the lab, led the effort.

    Additive manufacturing often is slow and expensive. It also may produce materials that are unreliable, Love says. So for two years, his team searched for ways to make 3-D printing better. They built new machines and tested them over and over.

    All of that work paid off: their new machine is fast and uses less expensive material than earlier printers. In addition, it prints a plastic embedded with fibers of carbon to produce a stronger material. This helps ensure the material won't crack or break under pressure.

    You use her as a shoulder to cry on. She texts you back with casual jokes. But she, Xiaoice, is only a virtual chatbot（虚拟聊天机器人）.

    Xiaoice, Microsoft's latest artificial intelligence robot, was briefly released in 2014, and returned to WeChat in 2015, where she became a big hit. Millions of young Chinese now exchange messages with her daily, The New York Times reported. On WeChat, Xiaoice is an official account. After following it, users can start text-based conversations with Xiaoice.

    “Her incredible learning ability was why people loved to talk with Xiaoice,” Liu Jinchang, a researcher at High-tech Research and Development Center under the Ministry of Science and Technology, told China Daily. Apart from her ability to identify photos and send emojis（表情符号） in conversations, Xiaoice gains 45 percent of her knowledge from interacting with users, China Daily reported.

    Chatbot programs first appeared in the mid-1960s in the US. Driven by top tech companies, they are becoming smarter and more common. For instance, IBM's latest artificial intelligence program served as an academic consultant at Australia's Deakin University, answering students' questions about course schedules and financial aid. Apple's Siri and Amazon's Alexa have been used as voice assistants who can read news, play music and even make jokes for their users.

    These programs are expected to move beyond smartphones, into televisions, cars and living rooms, The New York Times pointed out. However, it may take decades before scientists develop a “Samantha”, the advanced chatbot seen in the fiction film Her. In the film, Samantha has a romantic relationship with her user played by US actor Joaquin Phoenix. Many viewers were enthusiastic about this fantasy of virtual soul mates.

    Yesterday night, over a dinner with my elder brother's family, a topic of happiness came up. My wife, Marla, a psychologist, was sharing Csikszentmihalyi's concept of “flow” with us. Marla explained that according to the research on flow, people are happiest when they are absorbed in a task that is just challenging enough for them to experience a sense of mastery(熟练).

    A few moments later my brother, Yuri, offered the following opinion: “The first and only, necessary and sufficient factor for happiness is to stop associating happiness with pleasure. The two — happiness and pleasure — have nothing to do with each other.” This morning, with my cup of coffee, I searched through a pile of books on my bedside table and—at the bottom—found a book by Bertrand Russell, I started reading but didn't finish. In it, I found the following thought:

    “The human animal, like others, is adapted to a certain amount of struggle for life, and when by means of great wealth homo sapiens can gratify all his whims (突发奇想) without effort, the mere absence of effort from his life removes an essential ingredient of happiness.”

    The conversation came full circle: people are happiest when they are in a state of flow (Csikszentmihalyi's language )…which is the effortful devotion in a moment…which has nothing to do with pleasure.

    Indeed, as Yuri insisted : happiness–as–pleasure is a myth; the association between happiness and pleasure is nothing but a semantic(语义的) habit; psychologically, the two—happiness and pleasure—are arguably different; and breaking up this association between pleasure and happiness might, in fact, be a powerfully first step in pursuit of happiness.

    As I look back on that exchange, I recall that there was an effort, a struggle to find a common understanding about this seemingly difficult idea—a struggle that made me happy.

    When it comes to the most famous 20^th century painters of the United States, Grandma Moses should be mentioned, although she did not start painting until she was in her late seventies. As she once said to herself:" I would never sit back in a rocking chair, waiting for someone to help me." No one could have had a more active old age.

    She was born on a farm in New York State, one of five boys and five girls. At 12 she left home and was in domestic service until at 27 she married Thomas Moses, the hired hand of one of her employers. They farmed most of their lives, first in Virginia and then in New York State, at Eagle Bridge. She had ten children, of whom five survived; her husband died in 1927.

    Grandma Moses painted a little as a child and made embroidery(刺绣) pictures as a hobby, but only changed to oils in old age because her hands became too stiff(僵硬的) to sew and she still wanted to keep busy and pass the time. Her pictures were first sold at the local drugstore and at a market and were soon noticed by a businessman who bought all that she painted. Three of the pictures were exhibited(展览) in the Museum of Modern Art, and in 1940 she had her first exhibition in New York. Between the 1930's and her death, she produced some 2,000 pictures: careful and lively portrayals of the country life she had known for so long, with a wonderful sense of color and form. "I think really hard till I think of something really pretty, and then I paint it" she said.

    American writer and former president of Marvel Comics, Stan Lee, has died at the age of 95. The legendary comic book author died at Cedars Sinai Medical Center in Los Angeles, according to a family lawyer.

    Lee was born in 1922 to working-class Jewish immigrants from Romania. He began working at the comics section of Timely Publications—a company that would eventually transform into Marvel Comics – and became comic editor there at age 18. At age 40, Lee decided to give up on comics. But his wife Joan urged him to create the characters he always wanted to write as his comic swansong. And in 1961, Lee and artist Jack Kirby created 'The Fantastic Four'—fascinating characters with individual personalities and the golden age of comic books began. Many Marvel characters were groundbreaking at the time. For example, Black Panther was the first black superhero featured in a mainstream US comic. Other characters he created include the Ant Man, the X-Men, Iron Man, Captain America and Doctor Strange. In its heyday (鼎盛时期), Marvel sold 50 million copies a year. Lee was also known for appearing as a cameo (配角) in every Marvel film. Fans are very happy to look for Stan Lee in the films and after watching, they will definitely have a discussion online.

    Celebrities and fans have been sharing across social media how Lee and his work affected them. The CEO of Lee's Pow! Entertainment, Shane Duffy, called him "a true iconic pioneer with no comparable second". Hugh Jackman, who played Wolverine in the X-Men films, called Lee a "pioneering force in the superhero universe". Evangeline Lilly, who portrayed Ant Man's superhero partner, the Wasp, also shared his respect on Twitter. Chris Evans, the star of Captain America, wrote on Twitter: "For decades he provided both young and old with adventure, escape, comfort, confidence, inspiration, strength, friendship and joy. He expressed love and kindness and will leave an unforgettable mark on so, so, so many lives."

    "Smile!" I shouted, holding a yellow sign up on a busy street in Seattle. We were three thousand miles away from home on a Random Acts of Kindness and Volunteerism Road Trip. We had two aims. One was to try out our new "Smile!" signs and see how much kindness and joy we could spread in Pike Place Market. The other was to raise $80 by doing street performances, enough for gas to Portland and a small hotel room.

    We weren't sure how people would react (回应) to our signs. I nervously raised up our signs and shouted, "Hi, there!" to a young couple. They looked over and felt confused. Then they read our signs and broke into a smile. Before long, some tourists wanted to take a photo with us and some strangers stopped to ask us about our signs.

    In fact, we paid so close attention to our "Smile!" project that we forgot the other aim. Before we knew it, the sun was setting, and we had no money for our trip to Portland. We sat down to watch a blind musician play the guitar while thinking about what to do. He was packing up when a passing crowd kicked down his change bowl. He stumbled (绊倒) into the crowd. We rushed to help him, but another man moved more quickly to help him.

    Once the musician had his money safely returned, we ran over to meet the strange helper and said, "We just wanted to praise you for your good deed." He smiled, looking at our signs. "Your trip reminds me of something similar I once did when I was youn," he said. "Look! I'd like to donate (捐赠)." We told him, "No, thanks! We are fine. We've collected plenty of money." We lied. "Please let me donate. It will make me feel like I'm a part of this adventure," he insisted. And then the stranger opened his wallet and pulled out four $20 bills. The money was exactly what we had intended to raise that day. We were astonished. It seemed as if he had known somehow.