|
本文通过一路BBS站telnet客户端发布
Jennifer McDermott, New sonar designed to close technology gap. The Day,
July 29, 2010.
http://www.theday.com/article/20100729/NWS09/307299479/1018
Quote:
"Conventional sonar on U.S. surface ships, which has been around for decades
, transmits a pulsed signal through the water. Sonar operators listen for
the echo to return, and the signal is sent out again.
"Using Continuous Active Sonar, or CAS, the signal is transmitted constantly
and operators listen simultaneously for potential submarine sounds. This
technology will enable surface ships to detect submarines quicker, and from
a farther distance.
My comment:
(a) Both methods above are "active sonar." See
Sonar
http://en.wikipedia.org/wiki/Sonar
("Two types of technology share the name "sonar": passive sonar is
essentially listening for the sound made by vessels; active sonar is
emitting pulses of sounds and listening for echoes.")
(b) The Day (New London)
http://en.wikipedia.org/wiki/The_Day_(New_London)
(c) Alion Science and Technology
http://en.wikipedia.org/wiki/Alion_Science_and_Technology
(employee-owned defense contractor; founded in 2002; headquartered at McLean
, Virginia; revenue $750m)
I checked its web site (www.alionscience.com) just now, which says little
about sonar.
-------------------------Separately
(1)
(a) 中国海军三大舰队南海演习受到关注. BBC Chinese, July 30, 2010.
http://www.bbc.co.uk/zhongwen/simp/china/2010/07/100730_china_navy.shtml
(b) Yidi Zhao and Daniel Ten Kate, China Says Its South Sea Claims Are `
Indisputable.' Bloomberg News, July 30, 2010.
http://www.bloomberg.com/news/2010-07-30/china-has-indisputable-sovereignty-in-south-china-sea-defense-aide-says.html
("The Chinese government considers the entire South China Sea as its own,
dismissing claims from Southeast Asian countries to islands such as the
Spratlys, and is building an ocean-going fleet to project power beyond its
borders. China told Exxon Mobil Corp. and BP Plc to halt exploration in
areas that Vietnam considers part of its territory, according to U.S.
government agencies")
My comment: The report says, "China’s military recently held a large-scale
naval exercise in the sea using 'real weaponry,' Geng said." Other reports
use "live fire."
(c) Allison Jackson, China naval drill in South China Sea: state media. AFP,
July 30, 2010.
("It was not immediately clear if the two Chinese exercises were pre-planned
or a response to the four-day joint naval and air drill by the United
States and South Korea, which ended Wednesday")
My comment: There is no need to read the rest of the AFP report.
(2) John Pomfret, U.S. takes a tougher tone with China. Washington Post,
July 30, 2010.
http://www.washingtonpost.com/wp-dyn/content/article/2010/07/29/AR2010072906416.html?hpid=topnews
(a) Note: pitter patter (n; reduplication of patter)
patter (n): "a quick succession of light sounds or pats"
Both definitions are from www.m-w.com.
(b) Quote:
"Translated, it meant that China's claims to the whole sea were 'invalid,'
said a senior administration official, because it doesn't have any people
living on the scores of rocks and atolls that it says belong to China.
"Foreign Minister Yang reacted by leaving the meeting for an hour. When he
returned, he gave a rambling 30-minute response in which he accused the
United States of plotting against China on this issue, seemed to poke fun at
Vietnam's socialist credentials and apparently threatened Singapore,
according to U.S. and Asian officials in the room. 'China is a big country
and other countries are small countries, and that's just a fact,' he said,
staring directly at Singapore's foreign minister, George Yeo, according to
several participants at the meeting.
"But then China inserted itself into the debate, claiming that any military
exercise in the Yellow Sea would be seen as threatening to Beijing --
something that struck U.S. officials as unnecessarily complicating what was
supposed to be a simple message of U.S.-South Korean solidarity in the face
of an attack by Pyongyang. * * * But partly because China made an issue of
it, a second exercise is also being planned -- in the Yellow Sea. U.S.
officials also predicted that the George Washington will soon be back in the
region -- this time in the Yellow Sea.
My comment: Pay attention to "But partly because China made an issue of it."
--
|
发表于 7-30-2010 12:30:19
收藏
分享
支持
反对
楼主