無機材料化学 中間試験 参照可
１)次の(１)〜(８)の英文の（ ）の中に最も適当なものを答えなさい。
（１）The density of flat glass is ( @ )kg/dm3.
（２）Heat-absorbing glasses may absorb ( A )% of the visible light and ( B )% of the infra-red light.
（３）The lamination process is carried out in an autoclave at a pressure of ( C )kg/cm2 and a temperature of approximately ( D )℃.
（４）Cladding glasses are usually ( E )mm thick , depending on their surface area.
（５）The linear coefficient of expansion for flat glass , per unit change in temperature (℃) is ( F )x10-7 .
（６）At high temperature glass is a good conductor of electricity. If the resistivity is 1012Ω. cm at room temperature it may be as low as ( G )Ω. cm at 1400℃.
（７）The c.g..s. unit of heat is the calorie and is the quantity of heat required to raise ( H )g of water through 1℃.
（８）A window glazed with two panes of plate glass will transmit a maximum heat of ( I )kcal/h.m2 of the sun and sky radiations.
２）つぎの（１）〜（７）の英文の内容を説明しなさい。
（１）A VOLCANIC glass called obsidian was created by nature a long time before man learned how to make glass. This natural glass was used to make arrow heads, knives and similar tools.
（２）Some of the raw materials decompose during melting and give off large quantities of gases. When these gases pass up through the molten glass they help in stirring and homogenizing the glass. It is very important that the final glass has a homogeneous composition, in order to obtain constant physical properties. Before the glass is removed from the furnace it must also be free from bubbles, seeds and unmelted particles.
（３）The temperature , Tg, at which the bend occurs is called the transformation or glass-transition temperature. Only below Tg is it correct to describe the material as a glass. Between Tg and Tf the material is a supercooled liquid. At Tg the viscosity is extremely high - about 1013 poise.
（４）The basic units of the glass structure are the tetrahedral groups of SiO4 in which the central silicon atom is surrounded by four oxygen atoms (Figure 3.1). The SiO4 tetrahedra form a three-dimentional network in the glass. In crystalline forms of silica, e.g. quartz, the SiO4 tetrahedra form a regular network. In glass, however, the network is irregular. This indicates that glass is not a crystalline substance (Figure 3.2).
（５）The derkened colour of the glass is usually grey , sometimes tending towards brown or purple. These reactions are reversible and therefore the colour disappears when the light is removed and returns when the glass is exposed to light. Photochromic glasses contain silver halides which give rise to the reversible reactoins within the glass. They may be used as windows and sunglasses and as optical memory and self-erasing display devices.
（６）In 1959 Pilkington Brothers Limited presented their float glass process (Figure 2.10). The glass is melted in a tank furnace and a ribbon is formed by passing the glass through a pair of rollers. The ribbon of glass is then drawn across the surface of molten tin. Heat is applied to both surfaces of the ribbon and this ' fire polishing ' gives perfectly flat and parallel surfaces.
（７）The solar heat transmittance is thus apporoximately 65% higher if the Venetian blinds are put on the room side of the window than if they are placed between the panes of glass.
３）次の英文を和訳しなさい。
Lime and cementitious water will corrode glass very heavily. Rain water after having been in contact with a new cement joint or concrete may become very corrosive and it is important, therefore, to prevent it from flowing over the glass windows. It is usually very difficult to remove a cement deposit from a glass surface.