郑州激光矫正视力多少钱(郑州激光纠正近视时间多长) (今日更新中)

WASHINGTON, Nov. 16 (Xinhua) -- Data from NASA's Galileo spacecraft have provided scientists evidence of what appears to be a body of liquid water, equal in volume to the North American Great Lakes, beneath the icy surface of Jupiter's moon, Europa, the U.S. space agency announced Wednesday.The data suggest there is significant exchange between Europa's icy shell and the ocean beneath. This information could bolster arguments that Europa's global subsurface ocean represents a potential habitat for life elsewhere in our solar system. The findings will be published Thursday in the scientific journal Nature.Europa, which is slightly smaller than Earth's moon, is believed to have a large ocean of salty water deep beneath its frozen crust. Galileo spacecraft, launched by the space shuttle Atlantis in 1989, studied Jupiter, which is the most massive planet in the solar system, and some of its many moons.Pictures of it sent back by Galileo point to a tortured surface of cracks and jumbled ice. Seeking to understand how such weird topography evolved in a place with such dim sunlight, scientists believe that the answer lies in similar processes on Earth.Their model suggests that Europa's ice shell is about 10 kilometers thick and within it are giant pockets of water, lying at depths as shallow as three kilometers. Warm water from these sub-surface lakes wells up in plumes, causing the ice to become brittle, crack and then collapse. The ice turnover would be a plus for the prospects for life, as it would transfer energy and nutrients between the sub-glacial lake and the surface."One opinion in the scientific community has been if the ice shell is thick, that's bad for biology. That might mean the surface isn't communicating with the underlying ocean," said Britney Schmidt, lead author of the paper and postdoctoral fellow at the Institute for Geophysics, University of Texas at Austin. " Now, we see evidence that it's a thick ice shell that can mix vigorously and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable.""The data opens up some compelling possibilities," said Mary Voytek, director of NASA's Astrobiology Program. "However, scientists worldwide will want to take a close look at this analysis and review the data before we can fully appreciate the implication of these results."

NANJING, Dec. 8 (Xinhua) -- Chinese stargazers will have their best view of a total lunar eclipse in 10 years on Saturday if weather permits, the Zijinshan Astronomical Observatory under the Chinese Academy of Sciences (CAS) said Thursday.Wang Sichao, a research fellow with the observatory, said during the total eclipse, the full moon will not completely disappear from the Earth's shadow, but will take on a brilliant bronze color.He said the eclipse will be the best one seen in China since the last one occurred on Jan. 10, 2001."Theoretically, viewers can observe the eclipse from nearly everywhere in the country on Saturday," said the astronomer.He said the eclipse, the second this year, will last for 51 minutes. It will start at 8:45 p.m. and reach its climax at 10:06 p.m.Wang said Chinese viewers will have to wait until Oct. 8, 2014 to see the next total lunar eclipse.

SAN FRANCISCO, Nov. 12 (Xinhua) -- Apple has unveiled a worldwide replacement program for the first-generation iPod nano music player due to overheating battery issues, telling owners to stop using the product and get it replaced for free."Apple has determined that, in very rare cases, the battery in the iPod nano (1st generation) may overheat and pose a safety risk. Affected iPod nanos were sold between September 2005 and December 2006," said Apple in a notice posted late Friday on the support section of its official website.The company said the issue has been traced to a single battery supplier that produced batteries with a manufacturing defect. Since the product is five or six years old now, the likelihood of an incident increases.Owners of iPod nano can check the serial number on the back of the product to see if it is eligible for replacement. Apple promises a replacement unit about six weeks after the company received the affected one.The overheating battery issues of the first generation iPod nano have been known for years. In 2008, Japan's Ministry of Economy, Trade and Industry launched an investigation into Apple after dozens of iPod overheating cases were reported, including several incidents of iPod nanos toasting to the point of catching fire and causing minor burns to owners.Last August, a commuter train in Tokyo was delayed during rush hour when passengers complained of a strong burning smell from an overheating iPod nano that had burst apart.The portable music player also cost Apple a 22.5 million-U.S. dollar settlement in 2009 when a class action lawsuit in California alleged iPod nano is prone to scratches and its alleged defects were not disclosed by the company.

KUWAIT CITY, Nov. 27 (Xinhua) -- Two warships from China on Sunday docked at Kuwait's Shuwaikh port to start a five-day official visit to the Gulf Arab emirate.The tour by the destroyer "Wuhan" and the frigate "Yulin" marked the first visit by Chinese naval vessels to Kuwait since the two countries established diplomatic ties 40 years ago."This visit marks a historic occasion and Kuwaiti navy looks forward to future cooperation to improve the relationship and friendship between our two navies," said Colonel Khaled Ahmad Abdallah from Kuwait's navy.The flotilla was part of the ninth Chinese naval convoy to conclude its escort mission in the Gulf of Aden and waters off Somalia.Commander of the flotilla Guan Jianguo hopes the visit would enhance mutual cooperation between the two navies, which in turn would contribute to boosting bilateral relations.The flotilla would visit Oman after its stay in Kuwait.

BEIJING, Nov. 24 (Xinhua) -- China's Supreme People's Court vowed to harshly crack down on bribery, abuse of power and malpractice in food safety cases as such illegalities have become top concerns for Chinese people.Chinese courts at all levels had heard 173 cases and sentenced 255 people in relation to the production and sale of unsafe food in the first ten months of this year, Sun Jungong, spokesman of the Supreme People's Court (SPC), said Thursday."China has seen a growing number of food safety cases in recent years with increasing difficulties for investigation," Sun said.According to the SPC, Chinese courts handled 84 food safety cases in 2008, and 148 and 119 cases in 2009 and 2010, respectively. The number of food safety violators sentenced in the past three years totaled 101, 208 and 162, respectively.The SPC also promulgated four typical food safety illegalities exposed in recent years.In the latest food safety scandal, four people in central China's Henan province were prosecuted for the crime of "endangering public security by using dangerous means" in July after they were found to have produced and sold clenbuterol, a poisonous feed additive that pig farms use to boost the output of lean meat.The spokesman said the SPC will strengthen cooperation with police and procuratorial organs to improve the efficiency of dealing with, and preventing food safety crimes.

来源：资阳报