在电容器回路中串接串联电抗器，以改变电容器回路的阻抗参数，可限制（）。 A.高次谐波

如图1所示，一个质量m=0.1kg的正方形金属框总电阻R=0.5Ω，金属框放在表面绝缘且光滑的斜面顶端（金属框上边与AA′重合），自静止开始沿斜面下滑，下滑过程中穿过一段边界与斜面底边BB′平行、宽度为d的匀强磁场后滑至斜面底端（金属框下边与BB’重合），设金属框在下滑过程中的速度为v，与此对应的位移为s，那么v²-s图象（记录了线框运动全部过程）如图2所示，已知匀强磁场方向垂直斜面向上．试问：（g取10m/s²）

（1）根据v²-s图象所提供的信息，计算出金属框在进入磁场区域前下滑的加速度a，及从斜面顶端滑至底端所需的时间为多少？

（2）匀强磁场的磁感应强度多大？

（3）现用平行斜面沿斜面向上的恒力F作用在金属框上，使金属框从斜面底端BB′（金属框下边与BB′重合）由静止开始沿斜面向上运动，并匀速通过磁场区域后到达斜面顶端（金属框上边与AA′重合）．试计算恒力F的大小．

Culture means any human behavior that is learned in human society. All of the meaningful parts of a culture are passed on to different generations through tradition or social learning. From this view point, all human groups have a culture. Culture exists in agricultural as well as industrialized societies.

Culture is necessary for the survival and existence of human beings as human beings. Practically everything humans know, think, value, feel, and do is learned through taking part in a socio-cultural system. This statement is well supported by some well-written cases. Here is one of the cases of children growing up apart from human society. In the province of Kidnaper in India, the director of a children’s home was told by local villagers that there were “ghost（鬼）” in the forest. Upon looking into the case, the director found that two children, one about eight years old and the other about six years old, appeared to have been living with a pack of wolves in the forest. These children were the ghosts described by the local people. In his diary, the director describes his first view of Kamala(as the older child was named) and Amala(the name given to the younger child).

Kamala was a terrible-looking being—the head, a big ball of something covering the shoulders. Close at its heels there came another terrible creature exactly like the first, but smaller in size. Their eyes were very bright and sharp, unlike human eyes. They were very fond of raw meat and raw milk. Gradually, as they got stronger, they began going on all fours, and afterwards began to run on all fours like squirrels. Children learn human language in the same way they learn other kinds of human behavior by taking part in a cultural community. They learn a certain human language as well as certain kinds of human behavior through their membership in a certain cultural community.

1. From the passage we can learn that               .

A. human beings can develop human abilities only if they are raised by their biological parents

B. Amala and Kamala were raised in forest by ghosts

C. human beings will not grow up human unless they are raised by human beings in human culture

D. culture refers only to the high art and classical music of a particular society

2. Who were the “ghosts” of the Kidnapper forest seen by the local villagers?

A. They were two children Amala and Kamala, who ran on fours.

B. They were two squirrels, Amala and Kamala, who ran on fours.

C. They were two young wolves, Amala and Kamala, whose eyes were bright and sharp.

D. They were two children, Amala and Kamala, who were growing up in a children’s home.

3. How would you understand the description by the director “they began going on all fours,” in his

diary?

A. They began to continue with all their four eyes.

B. They started walking with their four feet.

C. They began going with their four hands.

D. They started walking with both their hands and feet.

4. Which of the following do you think is the best title to this passage?

A. Wolf-children                                   B. Culture and Human Behavior

C. Culture and Language Learning              D. A director’s Diary

简要说明环境中人为的放射性核素污染来源、向食品中的转移途径、对人体的危害及预防措施。

下列不属于城市燃气工程系统详细规划的主要的是( )。

A．估算分区燃气的用气量
B．规划布局燃气输配设施，确定其位置、容量和用地
C．规划布局燃气输配管网
D．计算燃气管网管径

空气斜槽输送细灰所需要的空气，可以从（）出口接入，或用小型离心式风机供给，风压一般在3～5kPa，风量约为1.5～2.5m／min。

A.引风机；

B.排粉机；

C.空压机；

D.送风机。