株洲系数控车床装调与维修考核实训设备(宜昌新能源纯电动车交流电机解剖模型) (今日更新中)

You can think of NASA's Discovery program as a sort of outer-space American Idol: every few years the agency invites scientists to propose unmanned planetary missions. The projects have to address some sort of fundamental science question, and (this is the tough part) they have to be relatively cheap to pull off — say, half a billion dollars or so. Then the proposals go through a grueling competition before judges who aren't as nasty as Simon Cowell but who are every bit as tough. The one left standing at the end gets the equivalent of a recording contract: NASA supplies the funding and the launch vehicle, and away the winner goes — to orbit Mercury, as the Messenger spacecraft is doing right now; or to rendezvous with a couple of asteroids, as the Dawn mission will start doing this July; or to smash into a comet on purpose, a feat achieved by Deep Impact in 2005, a mission not to be confused with the movie of the same name. Now it's time for the next contenders. NASA has just announced that the first round of the latest Discovery competition is over, with three entries out of 28 moving on to the finals. They are, in increasing distance from Earth: the Geophysical Monitoring Station (GEMS) lander, which would use seismometers to study the interior of Mars; the Comet Hopper, which would do just that, leaping from place to place across the surface of Comet 46P/Wirtanen to see how different parts of the tumbling body react to heating by the sun; and the Titan Mare Explorer (TiME), which would plop into a sea of liquid hydrocarbons on Saturn's moon Titan — the first oceangoing vessel ever to set sail on another world. If you had to come up with a theme that ties all three missions together, it would be "origins." The Titan explorer, for example, will be studying a place that — in a crude way, at least — resembles the early planet Earth at a time when life arose here. Titan, with a thick atmosphere and a bizarro-world form of weather featuring toxic winds and hydrocarbon rain, is home to a mix of complex chemistry, complete with organic molecules. The oceans provide a medium in which the molecules can move around and interact with each other. It's even conceivable, though clearly a long shot, that some form of microscopic life already exists on this frigid moon. The Mars lander, by contrast, would visit a place where the seas — plain water in this case — vanished long ago. But the mission of GEMS goes far deeper than that. By analyzing Marsquakes on the Red Planet, GEMS will try to get a handle on what the interior of Mars is like. Scientists don't currently know whether the planet's core is liquid, like Earth's, or solid, or some mushy consistency in between. It all depends on how efficiently Mars has cooled since it formed 4.5 billion years ago, and that depends in turn on the planet's internal structure. "That's the mission," says Bruce Banerdt, of NASA's Jet Propulsion Laboratory, the lead scientist for GEMS. "We want to understand how Mars was built." Along with sensitive seismographic equipment, GEMS will drill down about 20 ft. (6 m) with a thermometer-equipped probe, trying to figure out how quickly the temperature rises with depth. "That will let us extrapolate all the way down to the center," Banerdt says, "which will tell us how fast Mars is cooling."

NEW YORK, May 27 (Xinhua) -- U.S. stocks expanded gains on Friday ahead of the long Memorial Day weekend as surging commodity prices overcame disappointing economic data.European Central Bank Governing Council member George Provopoulos said that Greece might deal with its debt problem if it sticks to the aid program. That comment, which was considered as bullish by investors, drove the U.S. dollar weaker and led commodity prices surge on Friday.The stock market was driven by higher commodities prices, with thin trading volume ahead of the Memorial Day holiday, despite somewhat disappointing economic data on Friday.The Commerce Department said that both personal income and spending rose 0.4 percent in April, in line with market estimates. However, the rise in spending was the smallest in three months, suggesting the consumption situation was still weak.Meanwhile, pending home sales dropped 11.6 percent in April. The reading was a seven-month low. The market expectation was a drop of 1 percent.Moreover, the Thomson Reuters/University of Michigan Consumer Sentiment index came in above analysts' estimates. Concerns about higher gas prices and inflation had knocked the gauge down in March and April.Despite those disappointing data, analysts still held a bullish view toward the stock market. "Despite our near-term caution, we continue to see the S&P 500 reaching 1400 over the coming year," Alec Young, equity strategist of S&P Equity Research told Xinhua.According to Alex, while recent macro headwinds were raising questions about the sustainability of recent earnings momentum, he still believed that a downside trend of market was fairly limited and that the current weakness is more likely to be a correction, rather than the beginning of a new bear market."In our view, 2011 estimated EPS would have to be excessively optimistic to justify a bear market,"he added.The Dow Jones industrial average added 38.82 points, or 0.31 percent, to 12,441.58. The Standard & Poor's 500 was up 5.41 points, or 0.41 percent, to 1,331.10. The Nasdaq Composite Index rose 13.94 points, or 0.50 percent, to 2,796.86.

SAN FRANCISCO, March 30 (Xinhua) -- History records showed it was not often that large earthquakes caused immediate large volcano eruptions, a geophysicist told Xinhua on Wednesday while talking about whether the recent massive quake in Japan could trigger volcano eruptions.Inevitably, the shaking and changes in the state of stress in the crust could cause some changes in some of active volcanoes closest to the March 11 quake zone in Japan, said Dr. Jian Lin, senior scientist and geophysicist at the Woods Hole Oceanographic Institution in the United States.However, only if a particular volcano was already in a stage of magmatic inflation, a situation close to eruption, would the shaking make a major difference, he noted.Lin is currently visiting the U.S. Geological Survey's earthquake research center in Menlo Park, California to study the March 11 Japan earthquake.Compared with the cases that earthquake triggered volcano eruptions in the past, Lin said, most of active volcanoes in Japan are located somewhat farther away from the March 11 earthquake rupture zones. "The farther away, the less direct effect," he noted.Therefore, "the most important thing is to closely monitor all the active volcanoes in Japan," he said.There are only two well-documented cases of significant volcano eruptions that were apparently triggered by large earthquakes, he said.On Nov. 29, 1975, the Kilauea Volcano in the Hawaiian Islands had a small and short-lived eruption immediately after a magnitude- 7.2 quake hit the Big Island of Hawaii near the volcano, which was probably the best scientifically documented case so far of a volcano eruption triggered by a large earthquake.Records showed that the Kilauea Volvano was already in a stage of inflation before the quake. Meanwhile, the quake was right next to the volcano, which triggered the following eruption.Another case is 1960 Chile earthquake-volcano pair, in which a magnitude-9.5 earthquake, the largest ever recorded by instruments, could have triggered the Puyehue-Cordon Caulle Volcanic Complex ( PCCVC) into a violent eruption within 38 hours. The CCVC had been inactive for 25 years before the quake.Lin pointed out that like the Kilauea case, the earthquake rupture zone in the Chilean quake was again quite close to the volcanic group. However, little scientific monitoring data had been got for the PCCVC before its eruption as it is in a remote area in Chile.In recent years, scientists have observed that large earthquakes from long distance could trigger swarms of small earthquakes in active hydrothermal systems of volcanic regions, he said, noting that "these small earthquake swarms like these are not the same as volcano eruption."Lin added that the relationship between large volcano eruption and large earthquakes is still a poorly studied subject since scientific record is very short and many of large eruptions in the geological history were poorly documented."Therefore, we still know quite little about this subject," he said.

BEIJING, Feb. 20 (Xinhua) -- China's railways handled 7.13 million passengers Saturday, setting a new one day record, the Ministry of Railways (MOR) said Sunday.The figure was 16 percent higher year on year, the MOR said.Chinese railways are witnessing a new wave of travel after the Lantern Festival celebration (the 15th day of the first month in the Lunar New Year) Thursday, which is considered a symbolic ending of the festival season.China's Spring Festival fell on Feb. 3 this year.The busy Spring Festival transportation season runs for 40 days and is calculated in two phases: 15 days before the Spring Festival and 25 days after the Spring Festival.

NEW YORK, April 13 (Xinhua) -- New York City Mayor Michael Bloomberg and former U.S. President Bill Clinton announced on Wednesday the merger of their environmental groups, hoping to make it the most prominent climate policy organization in the world.The new organization would combine C40, a coalition of international cities run by Bloomberg, and the Clinton Climate Initiative, a project of Clinton' s philanthropic foundation, into a single organization, which will focus on population-rich cities to address global warming."I am elated by this. I think we really have a chance to make a difference," said Bill Clinton during a press conference at Gracie Mansion, adding that "together we are proving it is possible to create jobs and grow economies through reduced emissions."C40 and the Clinton Climate Initiative both seek to cut carbon emissions through programs that reduce energy use in buildings, promote mass transit and reuse greenhouse gases emitted by landfills.The newly combined organization is said to have a budget of about 15 million U.S. dollars. The group will have main offices in New York, Los Angeles and London.

来源：资阳报