在速率散射比浊分析中，不出现第二峰值信号提示（）。
A.抗原过剩，出现前带现象
B.抗原过剩，出现后带现象
C.抗体过剩，出现前带现象
D.抗体过剩，出现后带现象
E.抗原抗体均过剩，出现带现象
参考答案：B
解析：当在规定时间内反应介质中的抗体应将待测抗原全部结合，无游离抗原存在，此时再次加入已知相应抗原，该抗原与剩余游离抗体结合，而出现第二个峰值信号，故证明第一峰值信号是由全部待测抗原产生。反之，不出现第二次峰值信号说明待测标本中抗原浓度过高，抗原过剩，应进一步稀释后测量。
| The sun today is a yellow dwarf star. It is fueled by thermonuclear reactions near its center that convert hydrogen to helium. The sun has existed in its present state for about 4 billion, 600 million years and is thousands of times larger than the Earth. By studying other stars, astronomers can predict what the rest of the sun’s life will be like. About 5 billion years from now, the core of the sun will shrink and become hotter. The surface temperature will fail. The higher temperature of the center will increase the rate of thermonuclear reactions. The outer regions of the sun will expand approximately 35 million miles, about the distance to mercury, which is the closest planet to the sun. The sun will then be a red giant star. Temperatures on the earth will become too hot for life to exist. Once the sun has used up its thermonuclear energy as a red giant, it will begin to shrink. After it shrinks to the size of the earth, it will become a white dwarf star. The sun may throw off huge amounts of gases in violent eruptions called nova explosions as it changes from a red giant to a white dwarf. After billions of years as a white dwarf, the Sun will have used up all its fuel and will have lost its heat. Such a star is called a black dwarf. After the Sun has become a black dwarf, the earth will be dark and cold. If any atmosphere remains there, it will have frozen onto the earth’s surface. |
What will probably be the first stage of change as the sun becomes a red giant
A．Its core will cool off and use less fuel.
B．Its surface will become hotter and shrink.
C．It will use up its thermonuclear energy.
D．Its center will grow smaller and hotter.