搜题请搜索小程序“爱下问搜题”
问题 问答题 简答题

简述经济订货批量模型的前提假设有哪些？

答案

参考答案：

（1）需求率已知，为常量.年需求量以D表示，单位时间需求率以d表示

（2）一次订货量无最大最小限制

（3）采购，运输均无价格折扣

（4）订货提前期已知，为常量

（5）订货费与订货批量无关

（6）维持库存费是库存量的线性函数

（7）补充率为无限大，全部订货一次交付

（8）不允许缺货

（9）采用固定量系统

填空题

风筝在空中运动时，改变了空气流动情况，在风筝的背面空气流速大，因此，风筝的前面与背面出现了___________差，风筝前面受到的压力__________风筝背面受到的压力，使合力方向向_________，从而使风筝上升。
查看答案
填空题


Throughout history has (1) changed his physical environment in order to improve his (2) of life. With the tools of technology he has (3) many physical features of the earth. He has (4) woodlands and prairies into farms and made lakes and reservoirs (5) of rivers for irrigation purposes or hydroelectric (6) . Man has also modified the face of the earth by (7) marshes and cutting through mountains to (8) roads and railways.
However, man’s (9) to the physical environment have not always had beneficial results. Today, (10) of the air and water is an increasing danger to the health of the (11) . Each day thousands of tons of gases come out of the exhausts of motor vehicles. (12) from factories pollutes the air of industrialized areas and the surrounding (13) of the countryside. The pollution of water is equally harmful. The whole ecological (14) of the sea is being changed and (15) wastes have already made many rivers lifeless.
Now (16) protection is more pressing than ever before. As we know, massive destruction of the environment has brought about (17) effects and even poses a great (18) to man’s existence. Indifference to these problems will mean committing suicide. Therefore, effective (19) should be taken and laws passed to (20) the environment. Otherwise, man is certain to suffer from the serious consequences caused by this lack of care for his living surroundings.
查看答案