如图，在菱形ABCD中，AB=6，∠ABD=30°，则菱形ABCD的面积是（　　）

关于人口迁移对环境的影响，正确的叙述是（　　）

    After opening the world's first commercial Direct Air Capture plant（直接空气捕集工厂）designed to pull CO₂ out of the air, Swiss company Climeworks is now trying to create the world's first “negative emission（负排放）” power plant.

    An international team of scientists has been working on a way to turn captured CO₂ into minerals. The project is called CarFix. Experts capture the gas, put it into water and send it to more than 700 meters underground. There the CO₂ on contact with a special kind of rock forms into a mineral.

    “Our results show that between 95 and 98 percent of the CO₂, sent underground was mineralized over the period of less than two years, which is amazingly fast,” says lead author of the CarFix project, Dr. Juerg Matter. Before this discovery it was thought that this mineralization could take hundreds to thousands of years.

    The DAC technology can collect CO₂ from the atmosphere and then store it underground or sell it to business needing the gas. For example, customers can use it in drinks. And the first plant in Zurich is supplying the captured CO₂ to a nearby greenhouse to “feed” vegetables. By using the company's CO₂ the customers can reduce their carbon mission as well as lower their dependence on energy.

    A 2015 study suggested that before the CarFix project, experts could collect CO₂, but they didn't have a large-scale（大规模的）method to safely treat it.

    Combining Climeworks' DAC technology with the CarFix mineralization process they will be able to create a system. This system doesn't put additional carbon back into the atmosphere. Actually it is carbon negative.

    “The economic cost of applying this kind of carbon capture technology on a large-scale is not particularly practical now, but for the first time we are seeing a realistic and effective system,” says Christoph Gebald CEO of Climeworks.

    Self-driving vehicles will rely on cameras, sensors and artificial intelligence (AI) to recognize and respond to road and traffic conditions, but sensing is the most effective for objects and movement in the neighborhood of the vehicle. Not everything important in a car's environment will be caught by the vehicle's camera. Another vehicle approaching at high speed on a collision (碰撞) track might not be visible until it's too late. This is why vehicle-to-vehicle communication is undergoing rapid development. Our research shows that cars will need to be able to chat and cooperate on the road, although the technical challenges are considerable.

    Applications for vehicle- to-vehicle communication range from vehicles driving together in a row, to safety messages about nearby emergency vehicles. Vehicles could alert each other to avoid collisions or share notices about passers-by and bicycles.

    From as far as several hundred meters away, vehicles could exchange messages with one another or receive information from roadside units (RSUs) about nearby incidents or dangerous road conditions through 4G network. A high level of AI seems required for such vehicles, not only to self-drive from A to B, but also to react intelligently to messages received. Vehicles will need to plan, reason, strategize and adapt in the light of information received in real time and to carry out cooperative behaviors. For example, a group of autonomous vehicles might avoid a route together because of potential risks, or a vehicle could decide to drop someone off earlier due to messages received, a foreseen crowding ahead.

    Further applications of vehicle- to-vehicle communication are still being researched, including how to perform cooperative behavior.