The amount of heat released by steam when it changes to water at the same temperature is called（）.

A . Develop ductility B . Improve machining qualities C . Relieves stresses D . All of the above

A . centrifuging B . pressurizing C . atomization D . igniting

A . 97 times greater B . 94 times greater C . 10 times greater D . 2 times greater

A . New properties for better control of the JSF lifecycle B . Domino Designer built on top of Eclipse C . JavaScript interpreter performance D . End user experience / browser rendering

A . physical deformation B . state exchange C . chemical reaction D . coalescence

A . keep the propeller from being fouled B . increase propeller speed C . help calm the waves in the vicinity of the craft D . increase the holding power of the sea anchor

A . dry bulb temperature B . wet bulb temperature C . saturation temperature D . water vapor superheat

A . conductivity B . viscosity C . volume D . specific gravity

A . Overcoming sliding friction B . Overcoming rolling friction C . Overcoming fluid friction D . Overcoming oil wedge frictio

A . growth B . increase C . expansion D . extensio

A . In any case B . In case C . In no case D . In case of

A . eliminate hot air from the condenser B . maintain steady pressure in a system C . heat, or cool one fluid by means of another fluid D . reduce the engine room temperature in tropical climate

A . not good B . good C . better D . the best

A . conduction B . convection C . radiation D . windage

A．Y B．N C．NG

A．supplies B．receives C．provides D．requires

A．A B．B C．C D．D

A.the temperature equals B.equals the temperature C.does the temperature equal D.does the temperature equals

A．man can get heat from things like wood, coal and oil B．man cannot get the heat directly from the sun C．only wood, coal and oil have heat D．all the sun's heat is trapped in things

The first study was done at Duke University in Durham, North Carolina. Researchers pumped extra carbon dioxide into a test area where pine trees were growing. The trees grew thirty-four percent faster during the first three years. However, in time, the trees slowed to about their normal growth rate. The scientists say this is because trees need other nutrients, such as nitrogen. In the second study, researchers from Duke and Bowdoin College in Brunswick, Maine examined the soil around trees. They discovered that as the leaves broke down into the soil, all the carbon was not trapped in the soil. Much of it was released into the atmosphere as carbon dioxide. The findings of the two studies were published last month in Nature magazine. They suggest there is limited value in planting trees to reduce the carbon dioxide pollution in the atmosphere. Forest planting has been a part of negotiations on a world agreement to reduce greenhouse gases that scientists believe cause global warming. The United States, Canada, Japan and some other industrial countries have supported the idea. But this new research suggests the idea is not as effective as environmental activists had thought. Scientist Ram Oren of Duke University led the study on tree growth. He says that earlier estimates on the ability of forests to absorb carbon dioxide were overly hopeful. Some scientists not involved in the studies say the research provides some of the first evidence on how trees react to carbon dioxide. Other scientists say the research disputes a belief among some coal and power companies. The companies say that rising levels of carbon dioxide in the atmosphere will not create harmful global warming. Instead, they say it will increase forests and other plants. What is the purpose of this passage？ A．Introduce some new ideas about the relationship between trees and carbon dioxide. B．Introduce recent condition of global industrial pollution. C．Call on people to plant more trees to reduce greenhouse gases. D．Point out that power companies should be responsible for the rising levels of carbon dioxide.

A．sodium dodecyl sulfate （SDS） B．ammonium sulfate C．ferric phosphate D．phenol