Based on the theory of risk analysis, using the data related to water demand and supply of winter wheat in recent 40 years in North China, the risk probabilities of the different water demand and supply rates for non- irrigation or under conditions of irrigation for 1~5 times with the amount of 675 m/hm2 every time during the whole growing period of winter wheat were estimated.
依据风险原理,利用北方冬麦区近40年冬小麦水分供需的相关资料,基于灌水定额为675m3/hm2,估算了冬小麦全生育期无灌溉、灌1~5水条件下不同水分供需率等级出现的风险概率。
The paper chooses 365 cities to study the current situation of water demand,water supply and water shortage.
选取了全国365个城市作为研究对象,进行城市需水、供水和缺水分析,并按照六大分区统计汇总。
water demand forcasting is the effective way to plan and manage the water resources.
需水预测是进行水资源规划和管理的有效手段，尤其是在世界上不少城市和地区面临缺水局面的今天，如何合理而准确地预测未来的需水量以避免投资的浪费或减少将来用水危机的发生就显得更为重要。
The reliability and maintainability of spare in the process of equipment maintenance are studied in this paper,and the significant factors which have influence on spare demand rate are analyzed.
通过研究装备维修过程中器件的固有可靠性和维修性,着重分析了影响维修器件需求率的主要因素,利用系统建模和仿真的方法,分别针对耗损类型器件和可修复类型器件建立了相应的需求数学模型,最后给出了维修备件需求率的预计方法。
Stock model of economical order batch is established under the objective of maximum total profit according to the hypotheses of constant demand rate.
在需求率为常数的假定下,以总利润最大为目标,建立了确定性的经济订购批量存储模型。
The paper discusses a memory model whose demand rate is an arbitrary function.
讨论了一类推广的需求率为任意次函数的存贮模型 ,通过间接法给出了该模型的解析最优解 。
This suit needs dry cleaning and these shirts are to be washed .
这套衣服需要干洗，这几件衬衫需水洗。
isoline map of crop evapotranspiration
作物需水量等值线图
Not requiring water, as a cooling system.
不需水的，如一冷却系统
and necessities (food, water).
必需品(食物，水)。
More grain needed means more water needed.
需要更多谷物意味着需要更多的水。
These plants need watering every day.
这些植物需要每天浇水。
The garden is crying out to be watered
这个花园需要马上浇水。
We need numerous drinking water.
我们需要大量的饮用水。
We need some water and vegetables.
我们需要一些水和蔬菜。
We need someone to pour.
我们需要人斟茶倒水
biological aerobic treatment of wastewater
废水需氧生物处理法
seals without the application of moisture.
不需要用水就可以封口。
What do we need for the fruit salad?
做水果沙拉你需要什么？
The plants are starving for water.
这些植物极需要水。
The bathtub drain needs repairing.
浴盆的下水道需要修理。
Does electric - arc furnace need water too ?
电弧炉也需要水吗?
biochemical oxygen demand meter for seawater
海水生化需氧量测定仪
Water is essential for life – to drink, bathe, cook,clean, grow food, fuel engines, support ecosystems.
水是生命必需品，饮用、沐