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某化合物为无色结晶。mp．82～83℃，紫外光谱见蓝紫色荧光，异羟肟酸铁反应(+)，元素分析C 15 H 16 O 3 。 ：321，257。IR(KBr)cm -1 ：1720，1650，1560。 1 H-NMR(CDCl 3 )δ：1.66(3H，s)，1.81(3H，s)，3.52(2H，d，J=7Hz)，3.92(3H，s)，5.22(1H，t，J=7Hz)，6.20(1H，d，J=9Hz)，6.81(1H，d，J=8Hz)，7.27(1H，d，J=8Hz)，7.59(1H，d，J=9Hz)。MS m/z：[M] + 244(基峰)，229，213，211，201，189，186，159，131。 (1)计算不饱和度。 (2)写出完整的结构式。 (3)将氢核的位置进行归属。
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【单选题】In a single machine power system, the maximum power transfer from the generator to the system is directly proportional to ().
A.
bus voltage
B.
the system frequency
C.
the machine internal voltage
D.
the line reactance
【单选题】In the marine high voltage power system, _____.
A.
there is still low voltage AC power supply for some power and lighting loads
B.
there is only low voltage AC lighting system
C.
there is not low voltage AC power supply at all
D.
there is only low voltage AC power supply
【简答题】(V,D)表中的V代表( )。标识该路由可以达到的目的网络或目的主机；D代表( )，指出该路由器到达目的网络或目的主机的距离。
【单选题】How does the great power system of the twentieth century compare with that of the eighteenth and nineteenth centuries?
A.
The great power system in the twentieth century was global, whereas the great power system in the eighteenth and nineteenth centuries was European.
B.
The United States dominated the great power system of the twentieth century, whereas France dominated the great power system of the eighteenth and nineteenth centuries.
C.
The Concert of Europe was a feature of the great power system of the twentieth century, whereas the great power system of the eighteenth and nineteenth centuries saw constant conflict in Europe.
D.
World Wars I and II were major conflicts in the great power system of the twentieth century, whereas the great power system of the eighteenth and nineteenth centuries saw no major conflicts as Britain served as an effective balancer.
【单选题】The frequency of a power system is determined mainly by ( ).
A.
bus voltages
B.
active power generation
C.
reactive power generation
D.
active power generation and consumption
【单选题】The power supply system contains .
A.
start motor
B.
battery and alternator
C.
starting system
D.
cooling system
【单选题】在Excel2007中，在单元格A1中输入函数“=LEN('信息处理技术员')”，按回车键后，则A1单元格中的值为（）。
A.
7
B.
信息
C.
信息处理
D.
信息处理技术员
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