(单词翻译:单击)
听力文本
US Navy Cancels Development of High-Tech Railgun Weapon
The U.S. Navy is halting development of a high-tech weapon designed to fire projectiles at up to seven times the speed of sound.
The Navy spent more than 10 years developing the weapon, called an electromagnetic railgun. The cannon-like railgun uses electricity instead of chemical substances to fire projectiles.
A report released earlier this year by the Congressional Research Service stated that the Navy had been developing the railgun as a firing weapon to support U.S. Marines operations. The report said the development also centered on possible use of the railgun as a missile defense system.
The move to cancel railgun development comes as the U.S. Department of Defense turns its attention to the development of hypersonic missiles, The Associated Press reports.
Hypersonic is a term that relates to speeds of more than five times the speed of sound, also known as Mach 5. In addition to flying at extremely high speeds, hypersonic weapons are designed to move in ways that make them difficult to find and destroy in flight.
The U.S. military has been putting money into the development of hypersonic weapons in recent years in an effort to keep up with hypersonic military programs in China and Russia.
Matthew Caris is a defense expert with the private advisory company Avascent Group. He told the AP that "the railgun is, for the moment, dead."
The halt in railgun development, Caris said, suggests that the Navy saw difficulties in implementing the technology. In addition, the Navy likely recognized that hypersonic missiles have higher performing abilities than the railgun, he added.
Lieutenant Courtney Callaghan is a Navy spokesperson. She told the AP that the Navy's decision will free up resources for hypersonic missiles, as well as lasers and other electronic warfare systems.
The Navy spent about $500 million on research and development of the railgun, said Bryan Clark, a defense expert at the Hudson Institute.
The railgun held the possibility of providing an effective weapon at a much lower cost than smart bombs and missiles. Using electricity, a railgun can fire a projectile at six or seven times the speed of sound, creating enough energy to destroy targets.
But Clark said the program experienced a number of problems, including the limited range of the railgun in testing. In addition, its usefulness for missile defense was also limited by range and rate of fire, Clark added.
Another big question was whether the gun could stay together during continuous firing, said defense analyst Norman Friedman.
A normal gun can be fired about 600 times before the barrel has to be refurbished. But the barrel on tested railguns, Clark said, had to be replaced after about 12 to 24 shots were fired.
A few years ago, the Navy was talking about putting the gun on the future USS Lyndon B. Johnson, the last of three stealthy destroyers. But now, the Navy is developing what it calls a "hypervelocity projectile," which is designed to be fired from existing gun systems.
I'm Bryan Lynn.
重点解析
重点讲解：
1. in an effort to 努力想；试图要
The company has laid off 150 workers in an effort to save money.
公司为节省资金遣散了150名工作人员。
2. keep up with 赶得上；和...保持联系
She did not bother to keep up with the news.
她不愿操心去了解新闻。
3. free up 空出来；腾出来
The government has promised to free up more resources for education.
政府保证调拨更多资源用于教育。
4. In addition to 除了...之外
In addition to headaches, you may develop stomach ulcers as well.
除了头痛，你还可能患上胃溃疡。
参考译文
美军终止开发高科技电磁轨道炮为哪般？
美国海军将停止开发一种高科技武器，该武器能够以高达7倍音速发射弹丸。
美国海军花了10多年时间开发这种名为电磁轨道炮的武器。这种类似大炮的轨道炮利用电能而非化学物质来发射弹丸。
美国国会研究服务处今年早些时候发布的一份报告称，海军一直在开发轨道炮作为一种射击武器，来支持美国海军陆战队行动。该报告称，开发还集中于将轨道炮作为导弹防御的潜在用途。
据美联社报道，美国国防部将注意力转向高超音速导弹的开发之际，取消了轨道炮的开发。
高超音速是与超5倍音速的速度相关的术语，也被称为5马赫。除了以极高速度飞行以外，高超音速武器的移动方式在飞行中很难被发现和摧毁。
近年来，美国军方一直在投资开发高超音速武器，以追赶中俄两国的高超音速军事项目。
马修·卡里斯（Matthew Caris）是私人咨询公司Avascent Group的国防专家。他对美联社表示：“轨道炮目前已经画上句号了。”
卡里斯表示，停止轨道炮开发表明美国海军意识到了实现这项技术的困难。他还表示，此外海军可能认识到高超音速导弹比轨道炮具备更高的性能。
考特尼·卡拉汉（Courtney Callaghan）中尉是海军发言人。她对美联社表示，海军的这项决定将为高超音速导弹、激光以及其它电子战系统节省出资源。
哈德逊研究所的国防专家布莱恩·克拉克（Bryan Clark）表示，海军在轨道炮的研发上花费了大约5亿美元。
轨道炮仍有可能以比智能炸弹和导弹低很多的价格提供有效武器。轨道炮利用电能能够以6到7倍音速发射弹丸，产生足够大的能量摧毁目标。
但是克拉克表示，该项目遇到了许多问题，包括轨道炮在测试中的射程有限。克拉克补充说，此外它在导弹防御方面的作用也受到了射程和射速的限制。
国防分析师诺曼·弗里德曼（Norman Friedman）表示，另一个重大问题是这种大炮在连续射击时是否可以保持完整。
普通大炮在炮管必须翻修前可发射大约600次。克拉克表示，但是已测试轨道炮的炮管在发射大约12到24发后就必须更换。
几年前，美国海军还在讨论将轨道炮安装在未来的林登·约翰逊号驱逐舰上，这是3艘隐形驱逐舰中的最后一艘。而现在，海军正在开发一种能够从现有火炮系统发射的所谓“高超音速弹丸”的武器。
布莱恩·林恩为您播报。
译文为可可英语翻译，未经授权请勿转载！
