眼肌力测定法

Mercury Fillings Seem Safer over Time A study in the journal Chemical Research in Toxicology finds that mercury on the surface of dental fillings slowly turns to an inert sulfide compound, which should keep the mercury from harming the nervous system

发表于:2019-01-02 / 阅读(147) / 评论(0) 分类 60秒科学

EXPLORATIONS - September 18, 2002: National Cryptologic Museum By Paul Thompson German Nazi, American and Japanese coding machines. (Photo - Ed Bunyan) VOICE ONE: This is Mary Tillotson. VOICE TWO: An

发表于:2019-01-02 / 阅读(103) / 评论(0) 分类 Explorations

HEALTH REPORT – December 11, 2002: Mercury Levels in Fish By George Grow This is the VOA Special English Health Report. Two studies are adding to the debate about the health risks of eating fish con

发表于:2019-01-07 / 阅读(69) / 评论(0) 分类 健康与环境

I never considered myself unique, but people are constantly telling me, you are a miracle. To me, I was just an ordinary guy with realistic goals and big dreams. I was a 19-ye ar-old student at the University of Texas and well on my way toward fulfil

发表于:2019-02-02 / 阅读(134) / 评论(0) 分类 阅读空间

Craters here stretch as far as the eye can see. Although no human has ever set foot on Mercury, we have a pretty good idea of what you would see. If you are walking around on the surface of Mercury, it will look outwardly a lot like the moon. When yo

发表于:2019-02-05 / 阅读(65) / 评论(0) 分类 自然百科2012年

Many aspects, like its geological past, are a mystery. But some things we do know, this lonely planet has a strange sense of keeping time. Once you arrive, you have to reset your watch for a time zone like no other. It has such an unusual orbit and r

发表于:2019-02-05 / 阅读(60) / 评论(0) 分类 自然百科2012年

Mercury's core makes up about 60% of the planet by mass. It's about twice as big as earth. Why would it have such a huge core for such a small planet? Some people think there was a huge impact. Kind of stripped off a lot of the planet and now what we

发表于:2019-02-05 / 阅读(65) / 评论(0) 分类 自然百科2012年

After Messenger's 3 fly-bys, we've now mapped more than 90% of the planet. Taken from around 124 miles, these images are the clearest to date of Mercury. And it's not hard to spot a crater of epic proportions, the result of yet another Titanic collis

发表于:2019-02-05 / 阅读(78) / 评论(0) 分类 自然百科2012年

Reason/ you are going to go to Mercury as a travel destination would be this night sight view because it's going to be highly unique in the solar system. You have sodium thats atoms that are streaming off and giving enough to see yellow light, so you

发表于:2019-02-05 / 阅读(72) / 评论(0) 分类 自然百科2012年

Move away from the sun, and you'd expect things to cool down a little. Venus, the picture of coolness and calm, all pale but gully-cloaked by clouds but the planet of love is shrouded in mystery-----------draw beneath her treacherous veil at your own

发表于:2019-02-05 / 阅读(76) / 评论(0) 分类 自然百科2012年

You are there, on the most exciting, nerve-shattering journey in the history of man! Fifty years ago, it was easy for us to imagine Venus, closer to the Sun and wrapped in clouds, to be our scorched, tropical sister, swarming with life. There was thi

发表于:2019-02-05 / 阅读(81) / 评论(0) 分类 自然百科2012年

And thats the first time; it was return black-and-white panoramas of the Venus surface. These images were extremely important, because it was the first time, we ,human beings had a chance to see with our naked eyes completely different other world. W

发表于:2019-02-05 / 阅读(68) / 评论(0) 分类 自然百科2012年

In 1989, the space shuttle Atlantis launches the Magellan Probe toward / Venus. After a journey of 15 months, Magellan uses radar eyes to peer through the clouds from orbit. Watching form earth is Ellen Stofan. When you have that ability to pick up a

发表于:2019-02-05 / 阅读(73) / 评论(0) 分类 自然百科2012年

And its here in a freezer that Messenger will encounter another puzzle: can ice exist on a planet so close to the sun? It's only when the first radar observations to the surface of Mercury were obtained back in the 90s that it was discovered that Mer

发表于:2019-02-05 / 阅读(124) / 评论(0) 分类 自然百科2012年

On earth, Hawaii has some of the most spectacular shield volcanoes that are very similar with the volcanoes we see on Venus. The huge gently sloped volcanoes of Hawaii may be impressive. On Venus there are at least 150 ranging from this size to ten t

发表于:2019-02-15 / 阅读(109) / 评论(0) 分类 自然百科2012年

One of the really exciting and high-level scientific interests is whether Venus is geological active today, because there are reasons to think of the clouds on Venus only exist, because there is ongoing geological activity, so this is one of the bigg

发表于:2019-02-15 / 阅读(116) / 评论(0) 分类 自然百科2012年

Congratulations, you've arrived on the hottest surface in the solar system. Here, the official temperature is eight hundred seventy degrees Fahrenheit. Day or night, equator or pole, the searing heat never varies more than a few degrees, and thats wh

发表于:2019-02-15 / 阅读(132) / 评论(0) 分类 自然百科2012年

Despite all this scientific effort, we still don't know what triggered Venus' diabolical transformation. People debated over whether Venus ever had a moon. If Venus had a satellite at one point, could that satellite eventually impacted onto the surfa

发表于:2019-02-15 / 阅读(118) / 评论(0) 分类 自然百科2012年

Valor will be tackling the acid clouds of Venus with little help from flying pan technology. This being two weather balloons are we watched Venus in the mid-1980s. This with wagon machines there were two sep balloons that the Russians put them in the

发表于:2019-02-15 / 阅读(115) / 评论(0) 分类 自然百科2012年

You never guess the dangers on the ground from orbit, except maybe for this, massive, double-barreled storms hovering above the poles. Of this, what we called dipole features trailing around, we don't know what, really what they are, but the whole fe

发表于:2019-02-15 / 阅读(131) / 评论(0) 分类 自然百科2012年
学英语单词
a george
Acronychia pedunculata
act of self-help
amado
asklent
athletic type
attractees
avenues
basal pinacoid
bernard montgomery
Betula pubescens
busbar with detachable collar
cadenas
calcium bichromate
California dewberry
cerinum
ceruloplasmins
Challapata
child cry
chloromatous leukemia
crack sealer
debranchers
DEPOLYMN
desqview
disamenities of economic growth
Disasteridae
dramatisations
ebonyi
Exploitation-forest
fault-controlled
ferric trichloride
field tent
flange machinery
gold-pans
heat-stable plant
high-LET
iatrogenic infection
ice-skated
intermittent manufacture
ion exchange cellulose paper
irreparable
isophane insulin suspension (nph)
leaky butter
lengthwise piling
lever locking
levotransposition
lobsteins
loose tube cable attenuation
low-back
lowerings
lyocystidia
Lyuk
macroinferences
mean-root-square error
mesosa kuntzeni
mistion
monarda fistulosas
mooring pattern
multiflue chimney
natural language interface
offset error
original horizontal stratification
oyvind
pea-soup
Petit-Bassam
polygynian
polypedon
polypifers
provinour
put someone to the wall
pyronaridine
rated VA
re-appraisal
retinotopic
rock-filled cribbing
S-expressions
salmeton
sea worm
short pulse laser
sidas
slow flag
sodium phosphate monobasic
Sorbus multijuga
special survey of inert gas system
spiny dogfish
steam blanket
stormbeaten
subaggregate
subcontractable
tail-up on a rope
Temoptol
threatning
thuliums
to a proverb
truncated decision function
ud (oud)
ultrasonic spectroscope
urgent priority
vena renaliss
wedge shaped clip
zastavas
zero-gravity switch