采用后张法施工,如设计无规定,张拉预应力筋时,要求混凝土的强度至少要达到设计规定的混凝土立方体抗压强度标准值的()。
A. 0.85
B. 0.8
C. 0.75
D. 0.7
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石子与砂子的分界线为粒径()mm。
A. 4.5
B. 4.75
C. 5
D. 6
某项资产的风险收益率是市场风险溢酬与该资产系统风险系数的乘积。 ()
A. 正确
B. 错误
The human brain contains 10 thousand million cells and each of these may have a thousand connections. Such enormous numbers used to discourage us and cause us to dismiss the possibility of making a machine with human-like ability, but now that we have grown used to moving forward at such a pace we can be less sure. Quite soon, in only 10 or 20 years perhaps, we will be able to assemble a machine as complex as the human brain, and if we can we will. It may then take us a long time to render it intelligent by loading in the right software or by altering the architecture but that too will happen.
I think it certain that in decades, not centuries, machines of silicon will arise first to rival and then exceed their human ancestors. Once they exceed us, they will be capable of their own design. In a real sense they will be able to reproduce themselves. Silicon will have ended carbon's long control. And we will no longer be able to claim ourselves to be the finest intelligence in the known universe.
As the intelligence of robots increases to match that of humans and as their cost declines through economies of scale we may use them to expand our frontiers, first on earth through their ability to withstand environments, harmful to ourselves. Thus, deserts may bloom and the ocean beds be mined. Further ahead, by a combination of the great wealth this new age will bring and the technology it will provide, the construction of a vast, man-created world in space, home to thousands or millions of people, will be within our power.
In what way can we make a machine intelligent?
A. By making it work in such environments as deserts, oceans or space.
By working hard for 10 or 20 years.
C. By either properly programming it or changing its structure.
D. By reproducing it.
The motorcar will undoubtedly change significantly over the next 30 years. It should become smaller, safer, and more economical, and should not be powered by the gasoline engine. The car of the future should be far more pollution-free than present types.
Regardless of its power source, the auto in the future will still be the main problem in urban traffic congestion. One proposed solution to this problem is the automated highway system.
When the auto enters the highway system, a retractable arm will drop from the auto and make contact with a rail, which is similar to those powering subway trains electrically. Once attached to the rail, the car will become electrically powered from the system, and control of the vehicle will pass to a central computer. The computer will then monitor all of the car's movements.
The driver will use a telephone to dial instructions about his destination into the system. The computer will calculate the best route, and reserve space for the car all the way to the correct exit from the highway. The driver will then be free to relax and wait for the buzzer that will warn him of his coming exit. It is estimated that an automated highway will be able to handle 10,000 vehicles per hour, compared with the 1,500 to 2,000 vehicles that can be carried by a present-day highway.
One significant improvement in the future car will probably be ______.
A. its power source
B. its driving system
C. its monitoring system
D. its seating capacity