比是

因此认为，应用BP神经网络方法预测油田注采比是有效、可行的。

Therefore BP neural network method can effectively and practically predict oilfield injection-production ratio .

土壤微生物生物量C和N及其C/N比是反映土壤质量的重要生物学指标。

Soil microbial biomass carbon , nitrogen and its C / N ratio are the important biological indicators characterizing soil quality .

使在PCB上电子元器件的贴装具有良好的性能价格比是进行贴装工作的目标。

Cost effective placement of electronic components onto the PCB is the goal of the pick-and-place operation .

结果表明，前驱体碳化复合技术制备的TiFeC系反应喷涂复合粉末中C/Ti原子比是影响涂层相组成、显微结构和硬度的关键因素。

The results show that C / Ti atomic ratio has strong influence on the component , microstructure and hardness of TiC / Fe composite coating .

GA3与ABA的量比是种子休眠的关键因素。

The rate of GA_3 and ABA is a pivotal factor of the seed dormancy .

由于加窗插值FFT算法得出的幅值比是频率偏移量的N次多项式，同时复振幅的修正系数中不仅含有频率偏移量的N次多项式还有三角函数，计算量很大。

The amplitude ratio is N polynomial of the frequency offset , and the complex amplitude correction factor has N polynomial as well as trigonometric function . So it gets a lot of calculated amount .

对于Taylor模式的液体射流，射流速度、温度梯度、气液密度比是射流破碎的失稳因素，而液体黏度是液体射流破碎的促稳因素。

On the other hand , for a liquid jet under Taylor regime , jet speed , density ratio and temperature gradi - ent are all positive factors , whereas the liquid viscosity is negative factor .

本文第二章引入了一个类似于Malthus指数增长规律的模型，此模型可以存在一个全局稳定的两性指数解，但是种群的性比是趋向稳定的；

In the second chapter , a model similar to Malthus analogy is introduced , which supports an exponential solution which is globally asymptotically stable ; however , the sex ratio is stable .

分子束外延生长GaAlAs/GaAs量子阱材料时，适当的衬底温度和Ⅴ/Ⅲ束流比是改善AlGaAs材料生长质量的重要因素。

The GaAlAs / GaAs material with gradient refraction index quantum well structure has been grown by MBE . On the base of AlGaAs , GaAs fundamental material growth , excellent materials by the substrate temperature and ⅴ / ⅲ flux ratio optimization were achieved .

由于与光刻胶的刻蚀选择比较低，随着石英和BK7玻璃刻蚀深度的增加，图形转移精度下降。因此提高刻蚀选择比是获得高分辨率图形的前提。

Since the fidelity of pattern transfer degrades with the increasing of the etched depth , etching selectivity of photo-resist remains to be improved .

制作了直径为20mm的柱面驱动压电电动机，并对其输出特性进行测试，得到测试结果为输出力矩／质量比是0.426。

Finally a cylinder-driving piezoelectric motor with a diameter 20 mm is manufactured , and the test on its output characteristics is carried out . Result of the test shows that the ratio of output torque / mass is 0.426 .

位移和压缩比是经常使用的发动机规格。

Displacement and compression ratio are two frequently used engine specifications .

作为这种算法的应用，给出了一种脱线算法，其最坏情况绝对性能比是2。

It proves that the absolute worst - case ratio is 2 .

西北型日光温室最佳通风面积比是18%~25%。

The optimal ventilation area ratio is 18 % - 25 % .

加速比是并行程序的重要指标之一。

Speedup ratio is one of the key indexes of parallel programs .

广义方差比是一个效率度量。

The generalized variance ratio is a measure of efficiency .

黄金比是自然界物质最常见的自相似比例；

Golden proportion is most common self-similarity proportion of of objects in nature .

提高连铸比是优化钢铁企业结构的关键环节

Improvement in Concasting ratio ── key to optimization of structure of steel enterprise

混凝土配合比是工程施工的关键技术之一。

The proportioning of cement concrete is the key technology of the engineering ?

包合比是包合物加工的重要参数之一。

Host / guest ratio is one of the important parameters of IC .

泊松比是推测地球内部物质构成的有效参数之一。

The Passion ratio is an efficient parameter inferring the constitution of earth interior .

频带宽度与占空比是可控中子源的主要技术指标。

Frequency bandwidth and duty ratio are main specifications for the controllable neutron source .

甲状腺疾病发病率男女之比是1∶2.60，其中以甲亢差别最大、男女之比是1∶4.03。

The proportion between male and female is 1 ∶ 2.60 for incidence of thyroid diseases .

温度和C/N比是影响生物反硝化速率的2个重要参数，以反硝化生物膜为对象，研究了温度和C/N比对生物膜反硝化速率的影响。

Temperature and C / N ratio are the two important parameters affecting biological denitrification rate .

煤水比是水采矿井水提系统中最重要的运行指标之一。

The coal-water ratio is an important measure among others of the economics of hydromining operations .

曲轴的转速与凸轮轴的转速之比是2∶1。

The ratio of the crankshaft to the revolutions of the camshaft is 2 ∶ 1 .

涂层发射比对集热器的热效率影响较大，降低涂层发射比是提高集热器效率的有效途径；

And reducing the emission ratio of coat was an effective way to increase solar collector efficiency ;

在胶结充填采矿法中，选择一个恰当的水灰比是一件十分重要的工作。

In cemented filling method , to choose a proper water cement ratio is an important work .

电解温度、电解质初晶温度电解质分子比是铝电解过程的重要经济技术指标。

Bath temperature , liquidus temperature and cryolite Ratio are important parameters in Hall-Heroult for aluminum electrolysis .

在这两种不利因素中，是个女人比是黑人更糟。

Of the two handicaps , being black is much less of a drawback than being female .