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【单选题】
History of the Solar CalendarA Solar Calendar is a way of measuring and recording periods of time.It takes for the Earth to revolve around the Sun. With the help of the solar calendar, we can predict the times in which the sun will set and rise every day throughout the course of the year as well as the occurence of Solar and Lunar Eclipses when it is compared to the Lunar Calendar.The solar calendar was first developed by the Egyptians who used the annual appearance of the Dog Star-Sirius , which coincided with the yearly flooding of the Nile River, as a fixed point. However, the Egyptians forgot to consider the extra fraction of a day in their 365 day calendar. Later, the Roman republic calendar, based on the Lunar Calendar of the ancient Greeks, was replaced by Julius Caesar in favour of the Julian Calendar. The Julian Calendar allowed for February’s leap year but made the solar year too long by adding a quarter of a day annually. By the 16th Century, the extra time accumulated to form an error of around 10 days which was corrected in the form of the current Gregorian Calendar.In the Western World, the definition of the year is based on the Earth’s revolution around the Sun and, therefore, is referred to as a “Solar Year”. However, several varieties of Solar years exist:A Tropical Year lasts 365.242199 days UT and the name refers to the changes of seasons (from the greek ‘tropai’ meaning “the turning points”) which are fixed in this kind of year.A Sidereal Year lasts 365.256366 days UT and is the interval between two successive passages of the Mean Sun at the same star.What is the difference between a Lunar and Solar Calendar?There are 365 days in a solar calendar year and an additional day during leap years. In a Lunar calendar, there are 354 days and 384 in a leap year. A Lunar Calendar will shift very quickly in contrast to a solar calendar. 5. Which one is wrong about the solar calendar?
A.
The solar calendar was first developed by the Egyptians.
B.
The solar calendar coincides with the yearly flooding of the Nile River.
C.
In the Western World, the definition of the year is based on the Earth’s revolution around the Sun.
D.
A Tropical Year lasts 365.256366 days UT.
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【单选题】随着温度的升高,气体、液体的密度分别( )
A.
减小、增大
B.
减小、减小
C.
增大、减小
D.
增大、增大
【单选题】在RLC串联谐振电路中,增大电阻R,将使
A.
谐振频率降低
B.
谐振频率升高
C.
谐振曲线变平坦
D.
谐振曲线变尖锐
【单选题】在 RLC 串联谐振电路中,增大电阻 R ,将使( )
A.
谐振频率升高
B.
阻抗谐振曲线变尖锐
C.
阻抗谐振曲线变平坦
D.
谐振频率和阻抗谐振曲线都不变
【单选题】在RLC串联谐振电路中,增大电阻R,将使()。
A.
谐振频率降低
B.
谐振频率增高
C.
电流谐振曲线变尖锐
D.
电流谐振曲线变平坦
【单选题】从对流层到高层大气,随着高度的升高,会发生哪些现象? ①气温逐渐降低 ②气压逐渐降低 ③空气密度逐渐减小 ④臭氧含量逐渐减少 [     ]
A.
①②
B.
②③
C.
③④
D.
①④
【单选题】正截面受弯承载力图包住设计弯矩图,就可以保证
A.
斜截面受剪承载力
B.
斜截面受弯承载力
C.
正截面受弯承载力
D.
正截面受弯承载力和斜截面受弯承载力
【单选题】随着空气温度的升高,密度会越来越;
A.
B.
C.
不变
D.
无法确定
【单选题】刚性多层抹面水泥砂浆防水层中起防水作用的主要是 ( )
A.
结构层
B.
素灰层
C.
水泥砂浆
D.
水泥浆
【判断题】一般来说,超临界流体的密度介于气体和液体之间。随着压力的升高,同一超临界流体的密度可以类似气体的密度值连续的改变到类似于液体的密度值,且密度将随温度和压力的改变而发生很大的变化。
A.
正确
B.
错误
【多选题】甘草粉末的显微特征有
A.
纤维成束,晶鞘纤维较多
B.
具缘纹孔导管较大
C.
淀粉粒多为单粒
D.
木栓细胞多角形、红棕色
E.
棕色块状物
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