用于控制小动脉出血,如胃肠道、肾脏少量出血的短期可吸收栓塞剂是()
A.自体血凝块
B.明胶海绵
C.螺圈
D.鱼肝油酸钠
E.碘化油
参考答案:A
For more than two centuries, American’s colleges and universities have been the backbone of the country’s progress. They have educated the technical, managerial, (1) and provided generation after generation of national leaders. Today educators from around the globe are turning to U. S. institutions of higher learning (2) . They are apt to find many reasons for the excellence of American universities, but (3) stand out as watersheds: Education (4) : In 1862 Congress enacted the Land-Grant College Act, which essentially extended the opportunity of higher education (5) , including such disenfranchised groups as women and minorities. Each state was permitted to sell large tracts of (6) and use the proceeds to endow at least one public college. (7) : Over the years, the decentralization and diversity of the America’s colleges and universities have promoted competition for students and resources. Competitive pressure first arose (8) . The academy’s impact really grew after World War II, when (9) commissioned by President Roosevelt argued that it was the federal government’s responsibility to (10) for basic research. Instead of being centralized in government laboratories, scientific research (11) in American universities and generated increasing investment. It also gave graduate students research opportunities and helped (12) far and wide, to the benefit of industry, medicine and society as a whole. (13) : The end of the World War II saw passage of the Servicemen’s Readjustment Act of 1944. The law, which provided for (14) for returning veterans, made an already democratic higher-education system accessible in ways that were (15) in Europe, opening the doors of the best universities to men and women who had (16) of going to college. (17) : The creation of federal loan guarantees and subsidy programs, as well as outright grants for college students brought (18) to higher education and further helped to democratize access. Since its founding (19) , the Federal Family Education Loan Program has funded more than 74 million student loans worth more than (20) .
在做“探究串联电路中的电压规律”的实验时,有多个灯泡可供选择,小明把两只灯泡L1、L2串联起来接到电源上,如下图所示:
(1)当分别把电压表连在图中AB两点、BC两点及AC两点时,闭合开关后测得的数据是:UAB= 0,UBC= 12V,UAC =12V,则故障可能是________________________.
(2)故障排除后,实验正常进行,通过测量得到了两组实验数据如下表:
分析两组实验数据,可得出:__________________________________________.
(3)本实验设计你认为有什么不合理或可以改进的地方吗?若有,请加以说明(若是电路改进则填写在下边虚线框内).