某女性患者，67岁，因病态窦房结综合征植入AAI起搏器5年。近1周来反复出现头晕、乏力、黑矇。活动时动态心电图记录如下图所示。
如下图提示
A:起搏器故障 B:电极导线断裂 C:磁铁试验 D:肌电干扰 E:起搏器介导的心动过速
H.263
Instr（“abc@263.net”，”@”）的值是（）
A:4 B:3 C:5 D:6
http：//www.263.net/bbs/id=101765，这个URL各部分的正确含义是（）。
A:http是协议，表明主机是www服务器 B:http是服务名称，表示提供www服务 C:www.263.net是主机名 D:/bbs/id=101765表示当前页面的编号是101765
假如你的用户名为ajy，电子邮件服务商的主机名为263、net，你的E-mail地址为（）。
A:Ajy.263.net B:Ajy$263.net C:Ajy@263.net D:Ajy#263.net
牙冠短小，
力大，面无法制备出足够的空间。制作PFM全冠时金-瓷衔接线的位置应为（）
A:在舌侧距龈缘2mm处 B:面距颊侧边缘嵴lmm处 C:舌侧距边缘嵴2mm处 D:中央沟处 E:颊侧距颈缘2mm处
对于邮件地址apple．263．net，下列说法错误的是( )。
A:读作“at” B:表示“在”的意思 C:表示邮件apple在邮件服务器263．net上 D:表示邮件263在邮件服务器apple上
{{B}}第二篇{{/B}}
{{B}}
Superconducting Ceramic (陶瓷){{/B}}
? ?An underground
revolution begins this winter. With the flip (轻击) of a switch, 30,000 homes in
one part of Detroit will soon become the first in the country to receive
electricity transmitted by ice-cold high-performance cables. Other American
cities are expected to follow Detroit’s example in the years ahead, which could
conserve enormous amounts of power.
? ?The new electrical cables at
the Frisbie power station in Detroit are revolutionary because they are made of
superconductors. A superconductor is a material that transmits electricity with
little or no resistance. Resistance is the degree to which a substance resists
electric current. All common electrical conductors have a certain amount of
electrical resistance. They convert at least some of the electrical energy
passing through them into waste heat. ?Superconductors don’t. No one
understands how superconductivity works. It just does.
? ?Making
superconductors isn’t easy. A superconducting material has to be cooled to an
extremely low temperature to lose its resistance. The first superconductors,
made more than 50 years ago, had to be cooled to -263 degrees Celsius before
they lost their resistance. Newer superconducting materials lose their
resistance at -143 degrees Celsius.
? ?The superconductors cable
installed at the Frisbie station is made of a ceramic material that contains
copper, oxygen, bismuth (铋), strontium (锶), and calcium (钙). A ceramic is a
hard, strong compound made from clay or minerals. The superconducting ceramic
has been fashioned into a tape that is wrapped lengthwise around a long tube
filled with liquid nitrogen. Liquid nitrogen is supercold and lowers the
temperature of the ceramic tape to the point where it conveys electricity with
zero resistance.
? ?The United States loses an enormous amount of
electricity each year to resistance. Because cooled superconductors have no
resistance, they waste much less power. Other cities are watching the Frisbie
experiment in the hope that they might switch to superconducting cable and
conserve power, too. |
At what temperature does the superconducting ceramic lose its resistance?
A:-143 degree Celsius. B:-263 degree Celsius. C:As long as it is ice-cold. D:Absolute zero.
第二篇 Superconductor Ceramic(陶瓷)
An underground revolution begins this winter．with the flip(轻击)of a switch，30，000 homes in one part of Detroit will soon become the first in the country to receive electricity transmitted by ice．cold high．performance cables．Other American cities are expected to follow Detroit’s example in the years ahead．which could conserve enormous amounts of power．
The new electrical cables at the Frisbie power station in Detroit are revolutionary because they are made of superconductors．A superconductor is a material that transmits electricity with little or no resistance．Resistance is the degree to which a substance resists electric current．All common electrical conductors have a certain amount of electrical resistance．They convert at least some of the electrical energy passing through them into waste heat．Superconductors don’t?No one understands how superconductivity works．It just does．
Making superconductors isn’t easy．A superconductor material has to be cooled to an extremely low temperature to 10se its resistance．The first superconductors，made more than 50 years ago，had to be cooled to-263 degrees Celsius before they lost their resistance．Newer superconducting materials 10se their resistance at-143 degrees Celsius．
The superconductors cable installed at the Frisbie station is made of a ceramic material that contains copper．oxygen．bismuth(铋)。strontium(锶)．and calcium(钙)．A ceramic is a hard．strong compound made from clay or minerals．The superconducting ceramic has been fashioned into a tape that is wrapped lengthwise around a long tube filled with liquid nitrogen．Liquid nitrogen is supercold and lowers the temperature of the ceramic tape to the point where it conveys electricity with zero resistance．
The United States loses an enormous amount of electricity each year to resistance．Because cooled superconductors have no resistance．they waste much less power．0ther cities are watching the Frisbie experiment in the hope that they might switch to superconducting cable and conserve power．too．
At what temperature does the superconducting ceramic lose its resistance?
A:-143 degree Celsius． B:-263 degree Celsius． C:As long as it is ice-cold． D:Absolute zero．
257， 178， 259， 173， 261， 168， 263，( )
A:275 B:178 C:164 D:163
单选集
