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呼和浩特全口可拆标准模型
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钱江晚报

发布时间: 2025-05-28 05:41:09北京青年报社官方账号
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  呼和浩特全口可拆标准模型   

HONG KONG, Sept. 9 (Xinhua) -- The Hong Kong Polytechnic University (PolyU) announced Friday that its surveying experts had successfully developed methodologies for precise mapping of the Moon, after intensive analysis of the data captured by the Chinese lunar orbiter ChangE-1 and other lunar exploration missions.According to the PolyU, the team has made significant contributions to lunar mapping. Their efforts culminated in the development of a unique and innovative approach to the creation of accurate 3D models of the lunar surface.The team has produced the most updated parameters of the lunar figure (the shape of the moon), which is essential for lunar mapping using 17.5 million laser altimetry measurements from the ChangE-1and the Japanese SELENE missions.In addition, they also used the new topographic and gravity models to calculate improved crustal thickness and mass distribution of the Moon and established that the average thickness of the Moon's crust is about 40 km on the near side and 50 km on the far side.It was introduced that the resulting lunar mapping was the hard work of a dedicated research team led by Professor Chen Yong-qi, Emeritus Professor of the Department of Land Surveying and Geo-Informatics, who is also serving on the Expert Committee of China's Lunar Exploration Programme (ECCLEP), with the concerted efforts of team members Prof. Chen Wu, Prof. Ding Xiao-li, Prof. Baki Iz, Dr. Bruce King, and Dr. Wu Bo.According to Chen Yong-qi, the lunar mapping project started in 2006. The primary objective was to develop the methodologies and techniques for mapping the Moon surface, which is much more challenging than mapping the Earth's surface because of very few surveyed control points which are essential for accurate map making.Statistics showed that there were only fourteen lunar laser ranging retro reflectors (LRRR) and Apollo lunar surface experiment package (ALSEP) transmitter sites with accurately known coordinates available only on the near side of the Moon, installed by the U.S. Apollo and former Soviet Union Luna missions in the 1960s.Moreover, according to the team, the gravitational field of the Moon is not as well-known as that of Earth, which means the accuracy of the computed lunar satellite's position at any given time is lower than for Earth satellites, thus degrading the mapping accuracy and reliability.In addition, the team expressed that highly reflective lunar surface created significant problems for the automatic processing of images to develop 3D models using the technique of photogramemtry, which is a widely used and highly reliable technique for the creation of maps and 3D models on Earth.Furthermore, the team also revealed they had a plan to compare such data with other data sources in order to evaluate the performance of the ChangE mapping sensors. Since Chen Yong-qi is serving on the ECCLEP, the team has direct access to more recent data captured by the ChangE satellite.

  呼和浩特全口可拆标准模型   

  呼和浩特全口可拆标准模型   

SYDNEY, Aug. 16 (Xinhua) -- People sitting in front of TV for hours on end could shorten their life expectancy by almost five years, according to an Australian study published on Tuesday by the British Journal of Sports Medicine.Researchers from the University of Queensland estimate that for every hour adults spend in front of TV, their life expectancy shortens by almost 22 minutes.Those who watched six hours a day lived 4.8 years less than those who don't watch TV.The study is the first in Australia to look into how TV habits affect longevity.The Australian researchers found that watching TV could have a similar negative impact on life expectancy to that of obesity, smoking and low physical activity."People don't realize how it all adds up," the study's lead author Dr. Lennert Veerman told the Australian Associated Press (AAP)."They should try not to watch too much TV and find alternative things to do, preferably things that are light activities," Veerman said.The study was based on data from the Australian Diabetes, Obesity and Lifestyle study and asked more than 11,000 people aged over 25 about their weekly TV viewing time.The study found that in 2008 Australian adults watched 9.8 billion hours of TV."These findings suggest that substantial loss of life may be associated with prolonged TV viewing time among Australian adults," the study said."TV viewing time may have adverse health consequences that rival those of lack of physical activity, obesity and smoking; every single hour of TV viewed may shorten life by as much as 22 minutes," it said."With further corroborative evidence, a public health case could be made that adults also need to limit the time spent watching TV."Australians are recommended to spend at least 30 minutes a day doing moderate-intensity physical activity to reduce an increased risk of developing cardiovascular disease.

  

BEIJING, Sept. 4 (Xinhua) -- China's railway system has transported some 1.27 billion passengers during the first eight months of this year, up 11.8 percent from a year earlier, the Ministry of Railways said Sunday.The figure has accounted for 67.4 percent of the ministry's full-year target, said the ministry in a statement on its website.The Ministry of Railways has planned to send 1.9 billion passengers in 2011, up 13.1 percent year-on-year.The country's high-speed trains had been operating with improved order and efficiency, said the ministry, which has been required to run high-speed trains at slower speeds, as well as to reorganize bullet train schedules nationwide, for safety reasons.The State Council, or Cabinet, ordered increased safety checks after a fatal train collision that killed 40 people in July raised concerns over the safety of the country's high-speed railways.The ministry cut the number of high-speed trains running between Beijing and Shanghai to 66 pairs from 88 pairs per day, effective as of Aug. 16.Meanwhile, the railways transported more than 2.6 billion metric tons of goods from January to August, up 7.8 percent year-on-year, the ministry said.

  

TOKYO, Sept. 23 (Xinhua) -- Japan's H-2A rocket carrying a new information gathering satellite was launched at the Tanegashima Space Center in Kagoshima Prefecture on Friday, local media reported.Japan has already introduced three information-gathering satellites in the wake of a missile launch by Democratic People's Republic of Korea, and the latest one will replace the No. 2 satellite which has passed its use-by date, Kydo News said.Japan's H-2A rocket lifts off from the launchiung pad at the Tanegashima space centre in Kagoshima prefecture, Japan's southern island of Kyushu on September 23, 2011. Japan launched a new spy satellite into orbit September 23, officials saidThe development cost of the fourth satellite has reached 35.9 billion yen and its launch expenses have come to 10.4 billion yen, according to the government.The Japan Aerospace Exploration Agency and Mitsubishi Heavy Industries Ltd. were forced to put off the launch three times during the past four weeks due to the approach of a powerful typhoon and discovery of a system glitch. The rocket was initially scheduled to be sent into orbit on Aug. 28.

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