已选分类
工学
单选题高分子的主链结构对单键内旋转有重要影响。下列最易单键内旋转的主链结构是______。
单选题______ is not a true composite? A) Bamboo B) Human bone C) Safety glass D) Steel
单选题______ is not the common phenomena of thermoplastics deterioration. A．Weight loss B．Discoloration C．Swelling D．Cracking
单选题铸件薄壁处出现白口组织，造成切削加工困难。解决的办法是( )。 A．正火 B．等温淬火 C．石墨化退火
单选题fcc、bcc、hcp三种晶体结构的材料中，塑性形变时最容易生成孪晶的是______。
单选题Which is NOT the name ofthe recently discovered carbon structure that resembles a soccer ball? A) Buckyball B) C-60 C) Fullerene D) Graphite
单选题The force ofintermolecular attraction within the adhesive or adherend is defined as ______. A．Surface tension B．Adhesive bond C．Cohesive force D．Contact bonding
单选题Interface features are regarded as a type of adhesion phenomenon and are often interpreted in terms of the surface structure of the bonded material. Which are the major factors to be considered in explaining the adhesion phenomenon? A．The color, surface electric resistance, free radical groups, and roughness of the material to be bonded B．The weight, surface free energy, smell, and roughness of the material to be bonded C．The wettability, surface free energy, polar groups, and roughness of the material to be bonded D．The thickness, surface free energy, polar groups, and flatness of the material to be bonded
单选题置换型固溶合金中溶质原子的扩散是通过______实现。
单选题下列Burgers矢量可能表示了简单立方晶体中的全位错：
单选题六方晶系中晶面间距______晶面间距。(A)小于(B)等于(C)大于
单选题三元合金相图中，共晶反应的三相平衡的连接三角形应为______。
单选题Which of the following symbol is used to specify a family of directions in a crystal structure? A) ＜ ＞ B) ( ) C) [ ] D) {}
单选题长石属于______类型的硅酸盐结构。 A．岛状硅酸盐结构 B．层状硅酸盐结构 C．链状硅酸盐结构 D．架状硅酸盐结构
单选题铸铁与碳钢的区别在于有无______。 (A) 莱氏体 (B) 珠光体 (C) 铁素体
单选题Which statement is MOST TRUE about materials technology? A) Existing specifications and laws make it easy to introduce new materials in fields such as building construction and commercial aircraft. B) Materials Science and engineering usually follows the lead of developments in other technologies C) Industry and the consumer are quick to accept new materials and processes innovations D) Developments in materials science and engineering have allowed for innovations in most other technologies.
单选题大多数固相反应是由界面上的化学反应速度所控制的。
单选题A useful tool that is used to study the crystal structures of solids by measuring the angles of electrons glancing off material specimens. A．Electronmicroscope B．Opticalmicroscope C．X-ray diffraction (XRD) D．Differential thermal analysis (DTA)
单选题调质钢的含碳量大致为( )。 A．0.1/%～0.25/% B．0.25/%～0.50/% C．0.6/%～0.9/%
单选题玻璃在常温下能长期稳定存在，因而它是热力学稳定态。