The three cutting parameters for turning processing are ( ). A: cutting speed, feed and depth of cut B: cutting speed, workpiece rotational frequency and depth of cut C: workpiece rotational frequency, feed and depth of cut D: depth of cut, workpiece rotational frequency and feed

The piston moves up and down， thus causing the rotational movement of the（）

The main purpose of rotational grazing is to keep the chickens sufficiently active.（ ）

The main purpose of rotational grazing is to keep the chickens sufficiently active.（ ） A: 正确 B: 错误

The first condition for equilibrium(平衡) ensures that a body(物体) should be in translational(平动的) equilibrium; the second, that it be in rotational(转动的) equilibrium.

A sidereal day is shorter than a solar day. This difference is due to（）. A: irregularities in the daily rotational rate of the Sun B: the space motion of the solar system C: the precession of the equinoxes D: the use of different reference point

Which process involves dipping a seed crystal into a molten silicon liquid and pulling it upwards at a specific rotational speed? A: Multicrystalline ingot casting B: Float-zone pulling C: Czochralski casting D: Silicon wire casting

Which process involves dipping a seed crystal into a molten silicon <br/>liquid and pulling it upwards at a specific rotational speed? A: Multicrystalline ingot casting B: Float-zone pulling C: Czochralski casting D: Silicon wire casting

Read the following passage and then do the exercises (multiple choice) given below. Classification of Muscle Actions It is useful to be able to describe the effect of muscle contraction on a joint in terms which may be applied throughout the body and which are related to the anatomical position. The descriptive terms express very poorly, however, the complexities of movement, since they resolve movement to arbitrary planes of action. Flexion is the term used to describe the bending of a pan or the making of an angle, most easily visualized in the bending of the elbow or the knee. The opposite term extension fundamentally means a straightening. In the anatomical position most of the members of the body are in the extended position; the arms and legs are straight, as is also the back. In the case of the foot, these terms lead to some confusion since, in the erect position, the ankle is almost continuously semiflexed. From this position, further flexion is more readily understood under the term dorsiflexion and extension under the term plantar flexion. Plantar flexion is obviously bending in the direction of the sole; dorsiflexion, bending in the direction of the dorsum. For movement away from or toward the central axis of the body the terms abduction and adduction are applied. These terms lead to no confusion except in the hands and feel where there is movement of the digits away from and toward a plane wholly within these parts. Rotational movement is also recognized. Rotation of the anterior surface of a member toward the midplane of the body is medial rotation; rotation away from the midplane is lateral rotation. The rotary action of the forearm and hand, which can he readily observed as the hand is turned palm up or palm down, has a special designation. Pronation is rotation so as to turn the palm downward or backward; supination carries the palm upward or forward. There is a similar though less extensive movement of the foot in which rotation takes place in tile tarsal joints. The rotation of the foot so that the sole turns outward is eversion; the opposite movement so that the sole turns inward is inversion. A special case of rotation is that which is seen in the very important opposing action of the thumb. This movement of rolling the thumb over onto the hand so that the pads of the digits converge into a firm grasp is termed opposition; it is exhibited to a lesser degree in the little finger and in the great and small toes. Circumduction is circular movement; to produce this type of motion, flexion and extension, abduction and adduction are combined in a proper sequence. Special terms, such as protrusion and retraction, elevation and depression, will be referred to in their proper context but are relatively self-evident. a)Muscle actions in various patterns, have been mentioned this passage except________.