这些宇宙飞船燃烧化学燃料，而这些燃料非常昂贵。
These spaceships burn chemical fuels (燃料) and they are very expensive.
使用化学燃料火箭是多么的笨重。
激光需要的化学燃料或者电力还没办法轻易安置在太空。
Lasers also need chemical fuel or electrical power which is not readily available in space.
我们已经了解到化学燃料所能达到的一些限度。
We've reached kind of the limit of what chemical fuels can do.
这项技术作为化学燃料的替代而广受科学家推崇。
This technology has been pushed by some scientists as an alternative means of travelling around the solar system instead of conventional chemical fuels.
这样既可以节省珍贵的化学燃料，又可以延长航天器的寿命。
This saves valuable chemical propellant and extends mission lifetime.
化学燃料动力火箭可以提供克服地球引力所必须的强大推进力。
Chemical rockets have the high thrust necessary to lift rockets into space, overcoming the Earth's gravitational pull.
正是由于越来越多燃烧化学燃料导致了二氧化碳的增加。
It is the burning of more and more fossil fuels ____________________________ this increase in carbon dioxide.
带有核燃料火箭的宇宙飞船可在普通化学燃料火箭上发射。
The spacecraft, with its nuclear rockets, would be launched on top of a conventional chemical rocket.
同时，它可以取代化学燃料火箭来帮助卫星从近地轨道变轨至静止轨道。
In the meantime, it could replace chemical rockets for pushing satellites from low Earth orbit to geostationary orbit.
科学家们正在研制比目前化学燃料火箭飞行更快速的推进系统。
Scientists are already experimenting with propulsion systems that may travel much faster than today's conventional chemical rockets.
这些激光器一般利用化学燃料，通过各种单向反应直接驱动激射过程。
These lasers usually employ chemical combustion to energize directly the lasing process by various one-way reactions.
与化学燃料火箭相比，核燃料火箭能达到每秒大约22公里的最大速度。
Nuclear rockets, in contrast to their chemical counterparts, could impart a maximum velocity of up to about 22 kilometers a second.
同样，汽车开动过程中、制造过程中的化学物与化学燃料燃烧时都会释放出浮质。
Aerosols are also released when cars are driven, chemicals manufactured and fossil fuels burned.
有人可能会认为聚变推进需要一些能量高于标准的化学燃料一百多万倍的稀有燃料推进一个火箭。
One might think that fusion propulsion requires some exotic fuel to propel a rocket a million-or-so-times more energetically than standard chemical fuels.
但其排气速度却异常惊人，大约为化学燃料火箭的十倍—这使得离子推进器的效率非常高。
The exhaust velocity, though, is enormous—more than ten times that of a chemical rocket—and this makes ion propulsion extremely efficient.
广泛的以电力为驱动的空中旅行很不现实：飞机发动机需要高密度的能量，而这些只有化学燃料才可提供。
There is no realistic prospect for widespread electric air travel: the jet engines on aircraft need the high-energy density that only chemical fuels can provide.
他说，等得越久——即越晚使用如风能或太阳能之类的可再生资源替代化学燃料，遏制全球变暖的代价就越高。
He said costs of containing global warming, by switching from fossil fuels toward renewable energies such as wind or solar power, would rise the longer the world waited.
日本研究者们使用了一种高速原子力显微镜(afm)拍摄一部小旋转酶给电池产生化学燃料的电影。
Japanese researchers have used a high-speed atomic force microscopy (AFM) to shoot a movie of the tiny rotating enzyme that produces the chemical fuel for cells.
研究了不同复合固化剂对固体化学燃料各项性能的影响，确定了适合工业化生产的工艺条件和合理配方。
The effect of different kind of composite solidify agent on property of chemical fuel was studied and the proper process conditions and formula in commercial process were also determined.
如果仅仅使用化学燃料火箭，我们探索外层空间行星及其卫星的能力将受到限制，这是不难证明的事实。
It is an easily provable fact that with only chemical rockets, our ability to explore the outer planets and their moons is hindered.
这样，当普通燃料火箭到达地球轨道约800公里高度时，核反应堆舱会脱离化学燃料火箭，并开始工作。
Then, once the vehicle had ascended to high-Earth orbit, above about 800 kilometers, the nuclear reactor module would detach from the chemical rocket and start up.
麻省理工学院的一个研究小组发现了一种新颖的方式来模仿植物利用阳光的能量把水分解，形化学燃料来加速其成长的过程。
A team of MIT researchers has found a novel way to mimic the process by which plants use the power of sunlight to split water and make chemical fuel to power their growth.
如果我们能有廉价的方法将太阳能转化为可存贮、可运输、7x24小时可用的化学燃料，我们就迈向了人人可用的清洁能源。
If we could find a cheap way to convert solar energy into storable, transportable chemical fuels available 24/7, we would be well on our way to clean energy for all.
鉴于化学燃料火箭浪费太多的推进剂难以实现飞船速度的静变化，电力推进器仅仅使用一小点推进剂就可以做同样的任务。
Whereas chemical rockets waste too much propellant to reach a net change in spacecraft velocity, electric thrusters can do exactly the same mission using just a small fraction of the propellant.
从技术上讲，化学燃料火箭的最大速度增长比较低。这就是说，它们的排气速度还不足以将火箭的速度增加到非常快的程度。
In technical terms, chemical rockets have low maximum velocity growth, which means that their exhaust velocities are not high enough to impart very high speeds to the rocket.
因此长期以来，研究人员一直在设法利用太阳能来制造富含能量的化学燃料，如氢气、甲烷和汽油等，以便能够随时随地燃烧。
So researchers have long sought to use the energy in sunlight to generate energy-rich chemical fuels, such as hydrogen gas, methane, and gasoline, that can be burned anytime anywhere.
但是，在所用燃料量相同的情况下，化学燃料火箭所提供的能量较低，将宇宙飞船进行远距离发送时，这一点就是一个严重的缺陷。
But the relatively low amount of energy that they can deliver for a given mass of fuel is a severe drawback when dispatching spacecraft over long distances.
尽管，事实证明将玉米秸秆化学转变为可使用的液态燃料并非易事。
It turns out, though, that it's not so easy to do the chemistry that transforms a corn stalk into a liquid fuel that works.
尽管，事实证明将玉米秸秆化学转变为可使用的液态燃料并非易事。
It turns out, though, that it's not so easy to do the chemistry that transforms a corn stalk into a liquid fuel that works.
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