题目内容
描述飞机的飞行性能时需使用绝对高度。()
查看答案
搜索结果不匹配？点我反馈
更多问题
《中国共产党党内监督条例》针对当前党内监督存在的薄弱环节提出了明确措施，形成了新的制度安排，顺应了新形势新任务对加强党内监督的要求。()
Watching Microcurrents Flow
We can now watch electricity as it flows through even the tiniest circuits. By scanning the magnetic field generated as electric currents flow through objects, physicists have managed(46). The technology will allow manufacturers to scan microchips for faults, as well as revealing microscopic defects in anything from aircraft to banknotes.
Gang Xiao and Ben Schrag at Brown University in Providence, Rhode Island, visualize the current by measuring subtle changes in the magnetic field of an object and(47)
Their sensor is adapted from an existing piece of technology that is used to measure large magnetic fields in computer hard drives. "We redesigned the magnetic sensor to make it capable of measuring very weak changes in magnetic fields," says Xiao.
The resulting device is capable of detecting a current as weak as 10 microamperes, even when the wire is buried deep within a chip, and it shows up features as small as 40 nanometers across.
At present, engineers looking for defects in a chip have to peel off the layers and examine the circuits visually; this is one of the obstacles(48). But the new magnetic microscope is sensitive enough to look inside chips and reveal faults such as short circuits, nicks in the wires or electro migration -- where a dense area of current picks up surrounding atoms and moves them along. "It is like watching a river flow," explains Xiao.
As well as scanning tiny circuits, the microscope can be used to reveal the internal structure of any object capable of conducting electricity. For example, it could look directly at microscopic cracks in an aeroplane's fuselage,(49). The technique cannot yet pick up electrical activity in the human brain because the current there is too small, but Xiao doesn't rule it out in the future. "I can never say never," he says.
Although the researchers have only just made the technical details of the microscope public, it is already on sale, from electronics company Micro Magnetics in Fall River, Massachusetts. It is currently the size of a refrigerator and takes several minutes to scan a circuit, but Xiao and Schrag are working(50).
在一个部门或单位中，营造一个和谐宽松的工作环境影响着下属的心情。而这种环境的营造，良好的物质环境当然重要，但软环境也同样重要，而管理者就是软环境的建设者和维护者。你若被录用，该如何去营造这样的一个环境呢？
在其它条件不变的情况下,速度差越大,流体间的内摩擦力越小。()
微信支付 
支付宝支付