Explore the Materials——From an Atom to a Device（走进材料——从原子到器件）(北京航空航天大学) 中国大学mooc慕课答案2024版 m79713

Chapter 1 Materials and Devices： An Introduction 第一章测验

1、 The basic unit of materials is_____, which can bond directly together to form materials, or convert into ions, or assemble into molecules. 

答案: atom

2、 Crystalline structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material. We often use ____to illustrate the 3D structure, which is an array of ‘small boxes’ infinitely repeating in three spatial directions.

答案: crystal lattice

3、 Atoms could be bonded in different patterns, we call them chemical bonds. The three main types of chemical bonds are metallic, ionic and ______bonds. 

答案: covalent

4、 According to chemical composition, materials are usually classified as metals, _, polymers and ______. 

答案: ceramics;
composites

5、 The sequence of different scales is macro, mini, meso, ______, nano and atomic.
答案: micro

6、 According to the dominant material used by human being, the early development of mankind can be named as the Stone Age, the Copper age, the Bronze Age and the _____ age.

答案: Iron

7、 Atoms are made from even smaller particles. They are Protons, Neutrons and Electrons.

答案: 正确

Chapter 2 Metals and Alloys 第二章测验

1、 Metallic materials are mostly ______ in nature. 

答案: crystalline

2、 Based on the 3-dimensional configurations of atoms in crystals, all the crystal lattice structures can be classified as _ crystal systems and ______ Bravais lattice system.

答案: seven, fourteen

3、 As indicated in following figure, the crystal plane in the cubic cell could be written as _____. 

答案: (110)

4、 Steel is actually an alloy of _ and ___. 

答案: iron, carbon

5、 Which one is not the typical property of metallic materials?

答案: brittle

6、 Because of the strong bonding, metallic materials usually have high packing density. Typical lattice structures of metals include _, and __ structure. 

答案: body-centered cubic;
face-centered cubic;
hexagonal close-paced structure

7、 An alloy phase diagram is a graphical representation to show the relationships between the various phases that appear within the system under equilibrium conditions. In a phase diagram, usually composition is plotted on the x-axis and pressure is plotted on the y-axis.

答案: 错误

Chapter 3 Corrosion and Protection of Metallic Materials 第三章测验

1、 The majority of metal has a tendency to change into ______ gradually, except several noble metals, due to the exposure to the environment.

答案: metallic compounds

2、 Among various types of corrosions, _corrosion is the most common one. 

答案: electrochemical

3、 Al foils could keep shining, instead of corrosion. It’s because of____, which forms a very thin layer of oxidized film to inhibit Al for further corrosion.

答案: passivation

4、 Based on the inserted table of standard electrode potentials of metals, it could be inferred that ______ shows higher tendency to be corroded in aqueous solution at 25°C. 

答案: Zinc

5、 In order to reduce the loss from corrosion, we could use the following methods: ______. 

答案: electrochemical protection;
application of coatings;
appropriate materials selection;
suitable design

6、 The standard electrode potential of different metals in an aqueous solution could approximately show their thermodynamic stability.

答案: 正确

7、 The cathodic reaction is probably oxygen reduction reaction (ORR) when steel is corroded in an acid aqueous solution

答案: 错误

Chapter 4 Inorganic Non-metallic Materials 第四章测试

1、  ______is not the property of inorganic non-metallic materials.

答案: low melting temperature

2、  Which is not correct?

答案: The ordinary ceramic is not transparent because they are made of ultra pure raw materials.

3、 ______are the chemical bonds in inorganic non-metallic materials. 

答案: ionic bonds;
mixed bonds

4、 Choose the general properties of ceramics from the following

答案: Hard;
Wear-resistant;
Oxidation resistant

5、 The glass have various colors because they contain different metals or rare earth metals. 

答案: 正确

6、 Inorganic non-metallic materials have higher thermal conductivity than metals.

答案: 错误

7、 Which are correct in the following options?

答案: The ordinary ceramic is not transparent because they contain gas cavity.;
The ordinary ceramic is not transparent because they absorb lights and cause light scattering. ;
The ordinary ceramic is not transparent because they contain impurities.

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