复合材料(Composite materials)的概念是由()或()不同性质的材料,通过物理或化学的方法,在宏观上组成具有新性能的材料。
The purpose of this book is______.
A.to provide students with helpful and interesting material
B.to preface the Curriculum Guide with a brief account of biochemistry
C.to present inorganic and organic chemistry in details
D.to raise nonprofessional students' interests in chemistry
[A] cover
[B] change
[C] differ
[D] range
The primary reason for using a coupling agent(silane)in a resin composite is to()
A.stabilize its shade
B.improve its physical properties
C.provide it with a pleasant odor
D.make it more reflective
Sialic material refers to______.
A.the broken,rock resulting from the impact of a meteorite against the earth
B.material that exists on planets other than the earth
C.a composite of rock typical of continental areas of the earth
D.material that is man-made to simulate materials that existed far back in geological history
A.复合材料的某项性能等于组成复合材料各组分的性能之积
B.复合材料的某项性能等于组成复合材料各组分的性能之和
C.复合材料的某项性能等于组成复合材料各组分的性能除以该组分的体积分数之和
D.复合材料的某项性能等于组成复合材料各组分的性能乘以该组分的体积分数之和