在证据理论中,信任函数与似然函数的关系为()。
A:Bel≤Pl B:Bel<Pl C:Bel≥Pl D:Bel>Pl
2BEl系列瓦斯泵气量减少的原因及处理方法是什么?
2BEl系列瓦斯泵运转不正常的原因及处理方法是什么?
Astronomers are particularly interested in Eta Carinae because
A:it is in its final stage. B:it is a supernova. C:it exploded in 1987. D:it is brighter than the Sun.
下面有3篇短文,每篇短文后有5道题。请根据短文内容,为每题确定1个最佳选项。
{{B}}第一篇{{/B}}
? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ?
?{{B}}Sunspots{{/B}} ? ?It’s not surprising that sunspots (太阳黑子)
were observed by ancient astronomers (天文学家). The largest sunspots on the sun can
be seen without a telescope. It was not until the invention of the telescope
(望远镜) in the early 17th century, however, that systematic studies of sunspots
could be undertaken. The great astronomer Galileo was among the first to make
telescopic observations of sunspots. ? ?Sunspots are regions of
extremely strong magnetic fields (磁场) found on the sun’s surface. A sunspot has
a dark Central core known as the umbra. The umbra is surrounded by a dark ring
called the penumbra, where the magnetic field spreads outward. SunSpots appear
dark because they are giving off less radiation. They are cooler than the rest
of the sun’s surface. ? ?Sunspots are frequently observed in pairs
or in paired groups. The members of a spot pair are identified as the leading
spot and the following spot. They are identified by their position in the pair
in terms of the direction in which the sun rotates (旋转). ? ?The
number of sunspots at any one time varies. A large spot group may consist of as
many as 10 groups and 300 spots across the sun. The number of spots changes in a
fairly regular pattern called the sunspot cycle. The largest number occurs about
every 11 years. At sunspot minimum, there are at most just a few small
spots. ? ?The average lifetime of an individual spot group is
roughly one solar rotation, which is about 25 days. The most persistent large
spots,’ however, can survive for two to three
months. |
Careful observations and systematic studies of sunspots
A:were made by ancient astronomers B:started in the early 17th century C:were made by Galileo only D:could be made without a telescope
{{B}}第三篇{{/B}}
? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ? ?
? ? ? ? ? ? ? ? ? ?
?{{B}}Sunspots{{/B}} ? ?It’s not surprising that sunspots (太阳黑子)
were observed by ancient astronomers (天文学家). The largest sunspots on the sun can
be seen without a telescope. It was not until the invention of the telescope
(望远镜) in the early 17th century, however, that systematic studies of
sunspots could be undertaken. The great astronomer Galileo was among the first
to make telescopic observations of sunspots. ? ?Sunspots are
regions of extremely strong magnetic fields (磁场) found on the sun’s surface. A
sunspot has a dark central core known as the umbra. The umbra is surrounded by a
dark ring called the penumbra, where the magnetic field, spreads outward.
Sunspots appear dark because they are giving off less radiation. They are cooler
than the rest of the sun’s surface. ? ?Sunspots are frequently
observed in pairs or in paired groups. The members of a spot pair are identified
as the leading spot and the following spot. They are identified by their
position in the pair in terms of the direction in which the sun rotates
(旋转). ? ?The number of sunspots at any one time varies. A large
spot group may consist of as many as 10 groups and 300 spots across the sun. The
number of spots changes in a fairly regular pattern called the sunspot cycle.
The largest number occurs about every 11 years. At sunspot minimum, there are at
most just a few small spots. ? ?The average lifetime of an
individual spot group is roughly one solar rotation, which is about 25 days. The
most persistent large spots, however, can survive for two to three
months. |
Careful observations and systematic studies of sunspots
A:were made by ancient astronomers B:started in the early 17th century C:were made by Galileo only D:could be made without a telescope
Astronomers believe that matter in different parts of the universe( )
A:obeys different laws. B:obeys one common law. C:obeys the same laws. D:obeys no common law.
Astronomers believe that matter in different parts of the universe
A:obeys different laws. B:obeys one common law. C:obeys the same laws. D:obeys no common law.
1贝尔(Bel)等于______分贝(dB)。
1贝尔(Bel)等于( )分贝(dB)。
A:100 B:1 C:10 D:1000