篊ement is o ne of the most important material in project construction，Afterstudying the law of variable demand of fixed lifetime materials such as cement，we promptan optimal ordering policy model.
本文研究了水泥这类具有有限使用期的物资在施工中的需求变化规律，并提出了相应的最优订货策略。
pot life working life
适用期（有效使用期）
{You have tried to use an effective date that is the same as an existing effective date.}Use a different effective date.
{试图使用的有效日期和已有的有效日期相同。}请使用其他有效日期。
The Sealed Coupon is vaild and Should be used before the expiry date.
*本券盖章有效，在有效期内使用，过期作废。
To grant use or occupation of under the terms of a contract.
允诺使用在契约的有效期限内准许使用或占有
The maker guarantees this hair dye to stay on three weeks.
制造商保证染发剂使用后的有效期间为三星期。
The expiry date of condom is printed on each package,please use within valid date.
功夫王安全套包装上均标明使用期限，请在有效期内使用。
It can effectively restore the plump and healthy elasticity of the hair, suitable for long time use.
*有效恢复头发的丰盈和健康弹性，适合长期使用。
Where plastic dosimeters are used they should be used within the time-limit of their calibration.
塑料剂量指示剂应在其校正的有效期内使用。
The crammed shipping space complies our request for extension of credit validity.
船位拥挤使我们不得不延长信用证有效期。
The drug should not be used after the expiration date printed on the package.
本品在超过包装上印刷的有效期后不得使用。
Using the product on a long-term basis would keep skin moistening, healthy, tender and white.
长期使用本品，可有效改善皮肤质地，使皮肤亮丽嫣红、腻柔嫩。
First be sure that your license has not expired (usually 1 year).
首先请确保你的使用权并未过期(通常有效期是一年)。
"The term of reservation of such land shall be one year, But may be extended upon application by the joint venture within ten days before the expiration of the term. However, the extended period shall not exceed half a year."
预期使用土地的有效期为一年。期满前十天可申请延长预约期。延长预约期不超过半年。
an economic use of home heating oil.
家用燃油的有效使用.
Property used or occupied under the terms of such a contract.
租物在这种契约的有效期限内使用或占有的财产
The Home-Visiting Certificate for Compatriots from Hong Kong and Macao shall be kept by the certificate holder, and the period of validity of the Certificate shall be 10 years;within this period of validity, the Certificate can be used many times.
港澳同胞回乡证由持证人保存，有效期十年，在有效期内可以多次使用。
The Quality Department shall guarantee those devices have been verified and they are still within validity period.
质量部确保使用的监测和测量装置必须是经检定并在有效期内。
These additives shall be compatible with the contents and remain effective throughout the life of the body
这些添加剂必须与内装物质相容，并在箱体整个使用期间保持有效。