郑州500度近视不戴眼镜10年(郑州做眼睛近视手术哪家好一些?) (今日更新中)

WASHINGTON, June 9 (Xinhua) -- Observations from NASA's Voyager spacecraft suggest the edge of our solar system may not be smooth, but filled with a turbulent sea of magnetic bubbles, the U.S. space agency said Thursday in a statement.While using a new computer model to analyze Voyager data, scientists found the sun's distant magnetic field is made up of bubbles approximately 100 million miles wide. The bubbles are created when magnetic field lines reorganize. The new model suggests the field lines are broken up into self-contained structures disconnected from the solar magnetic field. The findings are described Thursday in the Astrophysical Journal.Like Earth, our sun has a magnetic field with a north pole and a south pole. The field lines are stretched outward by the solar wind or a stream of charged particles emanating from the star that interacts with material expelled from others in our corner of the Milky Way galaxy.The Voyager spacecraft, more than nine billion miles away from Earth, are traveling in a boundary region. In that area, the solar wind and magnetic field are affected by material expelled from other stars in our corner of the Milky Way galaxy."The sun's magnetic field extends all the way to the edge of the solar system," said astronomer Merav Opher of Boston University. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are, the folds of the skirt bunch up."Understanding the structure of the sun's magnetic field will allow scientists to explain how galactic cosmic rays enter our solar system and help define how the star interacts with the rest of the galaxy.So far, much of the evidence for the existence of the bubbles originates from an instrument aboard the spacecraft that measures energetic particles. Investigators are studying more information and hoping to find signatures of the bubbles in the Voyager magnetic field data."We are still trying to wrap our minds around the implications of the findings," said University of Maryland physicist Jim Drake, one of Opher's colleagues.Launched in 1977, the Voyager twin spacecraft have been on a 33- year journey. They are en route to reach the edge of interstellar space. NASA's Jet Propulsion Laboratory built the spacecraft and continues to operate them.

BEIJING, Sept. 9 (Xinhua) -- Lenovo Group, China's largest PC maker, said it aims to become the world's second-largest PC provider by the end of this year, China Daily reported Friday.The PC maker will take aggressive action to expand in the international PC market left by its competitors because of strategy adjustment, the English newspaper quoted Liu Chuanzhi, the board chairman of Lenovo, as saying.A few weeks ago, the world's biggest PC maker Hewlett-Packard Corp. said it will spin off its PC sector. Apple Inc's former CEO Steve Jobs resigned."The Chinese market is the starting point for Lenovo, but it won't be the only place Lenovo should put emphasis on. We will set up a more active strategy for expanding in overseas markets," Liu said.The PC maker has long been focusing on the global market. It purchased the PC division of the IBM Corp. a few years ago. In January, it announced a 175-million-U.S.-dollar joint venture with Japan's NEC Corp. In July, Lenovo completed its acquisition of Medion AG, a German multimedia and consumer electronics maker.

WASHINGTON, Aug. 17 (Xinhua) -- Latest research shows that the Moon could be younger than previous estimates. The findings were published online Wednesday in the Nature journal.The prevailing theory of the Moon's origin is that it was created by a giant impact between a large planet-like object and the proto-Earth. The energy of this impact was sufficiently high that the Moon formed from melted material that was ejected into space. As the Moon cooled, this magma solidified into different mineral components. Analysis of lunar rock samples thought to have been derived from the original magma has given scientists a new estimate of the Moon's age.According to this theory for lunar formation, a rock type called ferroan anorthosite, or FAN, is the oldest of the Moon's crustal rocks, but scientists have had difficulty dating FAN samples. The research team used newly refined techniques to determine the age of a sample of FAN from the lunar rock that was brought back to Earth by the Apollo 16 mission in 1972.The team analyzed the isotopes of the elements lead and neodymium to place the FAN sample's age at 4.36 billion years. This figure is significantly younger than earlier estimates of the Moon's age that range as old as the age of the solar system at 4. 568 billion years. The new, younger age obtained for the oldest lunar crust is similar to ages obtained for the oldest terrestrial minerals -- zircons from western Australia -- suggesting that the oldest crusts on both Earth and Moon formed at approximately the same time, and that this time dates from shortly after the giant impact.This study is the first in which a single sample of FAN yielded consistent ages from multiple isotope dating techniques. This result strongly suggests that these ages pinpoint the time at which the sample crystallized."The extraordinarily young age of this lunar sample either means that the Moon solidified significantly later than previous estimates, or that we need to change our entire understanding of the Moon's geochemical history," Carnegie Institute of Science's geochemist and study author Richard Carlson said.

CANBERRA, Sept. 1 (Xinhua) -- Bushranger Ned Kelly's headless body has finally been identified in Australia, more than 130 years after his execution in the Old Melbourne Gaol, Victoria's Attorney- General Robert Clark announced on Thursday.Clark said the bushranger's remains have been identified by doctors and scientists at the Victorian Institute of Forensic Medicine (VIFM).Kelly was an Irish Australian bushranger, considered by some merely a cold-blooded killer, while by others a folk hero and symbol of Irish Australian resistance against oppression by the British ruling class for his defiance of the colonial authorities. He was hanged for murder in 1880 at Old Melbourne Gaol. His daring and notoriety made him an iconic figure in Australian history, folklore, literature, art and film.The project involved collaboration with the ancient DNA laboratory EAAF in Argentina, which has worked with the VIFM on other forensic projects.Clark said "This is an extraordinary achievement by our forensic team here in Victoria," he told reporters in Melbourne on Thursday."To think a group of scientists could identify the body of a man who was executed more than 130 years ago, moved and buried in a haphazard fashion among 33 other prisoners, most of whom are not identified, is amazing." The investigation started when a skull believed to belong to Kelly was handed to the VIFM on Nov. 11, 2009.The skull handed in in 2009 was found not to be that of Ned Kelly, and Glenrowan historian Gary Deans said the next step is to find Kelly's skull."The Government should put a request in the public arena for the return of Ned Kelly's skull," he told ABC News."We know thanks to Jack Cranston, who held the skull around 1929, that it was sitting on a detective's desk. This was around the same time that remains were dug up in the Old Melbourne Gaol."I imagine that that detective or somebody else took it home."

VIENNA, Aug. 11 (Xinhua) -- Austrian researchers have developed a method of using fungi and produced enzymes to split Polyethylene Terephthalate (PET) material into their initial state, enabling the recovery of all individual components, said the Austrian Center of Industrial Biotechnology (ACIB) Thursday in a press release.Enzyme is a special protein that acts as biological catalyst, for example, bacteria and fungi in the nature can break down long chain molecules.Researchers from the Technical University of Graz, the Technical University of Vienna and the Agricultural University of Vienna jointly found that efficient enzymes are capable to break and split PET into small fragments.With different methods, the researchers forced the fungi to overproduce their precious "split-tools" after they are modified and improved by genetic engineering.Through the new method developed by the ACIB, it is now possible to decompose the PET polymer to its initial monomers with high product quality and from this to produce new high-quality materials again.This circuit avoids waste and thus saves resources and is friendly to the environment, said Geog Guebitz, head of the Research Department on Enzymes and Polymers in the ACIB.He further explained that the ACIB has established a partnership with some industrial enterprises to carry out application experiments. From the current splitting time of 24 hours, the researchers expect to shorten the whole process to "a few hours," he added.PET is a common plastic material in the polyester family, widely used in the textile industry. PET film is mainly used in electrical insulation materials, which can be also used for production of film, X-ray films and computer taps, even to produce plastic bottle and other blow molding products.

来源：资阳报