Calculation method of piston air induced by train motion in subway tunnels is derived based on fluid continuity equation and Bernoulli equation. Further qualitative analysis is carried out on some key factors affecting the piston effect.

Bernoulli's equation is an important equation in fluid mechanics. The equation has different forms for various fluid flow. The note analyses and gives Bernoulli's Equation for incompressible fluids compressible gases and viscous fluids.

伯努利方程是流体力学中的一个重要公式，对于不同的流体流动方程的形式不同，本文分析并给出了不可压缩流体、可压缩气体和粘性流体的伯努利方程。

On the pressure-energy in the Bernoulli' sequation

浅谈伯努利方程中的压强能

The prominent characteristics of gear pump in application to flow metering and fluid transportation were introduced in this article.

文章介绍了流体力学理论如何和流量计量结合，给出连续性方程和伯努利方程在流量上的推导和经典的应用。

Bernoulli equation in human body

人体中的伯努利方程

We are charged with finding a safe passage for a single surface ship and fliers.

所以我们奉命寻找一条能容一艘水面舰船和快艇通过的安全通道.

Torpedo has been the mainly threat to large surface ship and submarine.

鱼雷已经成为大型水面舰和潜艇的最大威胁.

Every surface ship is not equipped with anti-ship missiles.

并非每艘水面舰艇都装备有 反 舰导弹.

Xiao Zhang has been Xiao Yuan's teacher for years but they rarely have chance to meet.

小张和小袁是多年西席,却一直难得一见.

Teacher Zhang is our family tutor, and we respect him very much.

张老师是我们家的西宾, 我们都很尊重他.

While the equivalent energy way will simplify the group into a new group of two linear equations and it increases the computing speed and accurancy.

而采用等效能量法后，可以将这个积分方程组转化为一个二元一次线性方程组来进行求解，从而提高了计算的速度和准确度。

By use of the continuous conditions between adjoining sections, ge-neral formulas of internal forces and displacements are derived and the prob-lem finally becomes to solve a simultaneous linear equations with two unk-nowns.

然后给出每一小段用初参数表示的解，再利用各段之间的连续条件，给出内力与位移的一般表达式，并最后将问题归结为一个二元一次方程组的求解。

A computer system that learns to solve simultaneous linear equations from examples

计算机通过样例学习解二元一次联立方程

Methods: The length of cervical spinal curving strings and arcs were measured on middle potential lateral radiographs in 378 normal persons cervical spines by computer imaging processing system, and the physiological curvature were figured out through solution of dualistic once equation.

方法：采用计算机图像处理技术，对378例正常人体颈椎中间位侧位片弦、弧长度进行测量，通过二元一次方程求解计算出正常颈椎生理曲度。

Case of Teaching about the Application of Binary Linear Equation Group

初中代数教学中的数学情境与提出问题&二元一次方程组的应用教学案例

Configuration feature: Constant green undershrub, its individual plant can amount to 1 meter high.

形态特征: 常绿小灌木, 其株高可达1米.

Introduced the work flow and database design of the system, took the quadratic equation with one unknown in math course of middle school as an example and demonstrated the study diagnosis process under the two models.

介绍了系统的工作流程和数据库设计。以初中数学中的一元二次方程章节为例，演示了系统在两种模式下对学生的知识状态进行诊断测试的过程。

After deriving Swt from the model, we find out that the water saturation equation is a quadratic equation about Swt, so its solution is very simple and obtained by using the standard quadratic-root formula.

通过研究混合泥质砂岩有效介质通用HB电阻率模型的求解方法，表明模型导出的关于S（wt）的方程是一个一元二次方程，可用求根公式求解，解法非常简单。

The method solves an algebraic equation instead of a set of nonlinear differential equations to find the two initial conditions for the periodic relative rotating orbits for any eccentric orbit with nonlinear relative motion.

该方法不用求解非线性相对运动微分方程，只需解一个一元二次代数方程，就可给出任意偏心率和非线性条件下，两个具有明显物理意义的周期性相对运动初始条件。

The Properties of the Real Root of Equation of One-place 2-th Order

含参数一元二次方程根的性质

Based on single quadratic equation of nitrogen, phosphorus and potassium under suitable fertilization rate, the optimum amount of N fertilizer among years had significantly increasing trend, the one for P fertilizer increased and K fertilizer with a slightly increase.

据适宜施肥条件下水稻氮、磷、钾单因素一元二次肥效方程分析，氮肥最佳施用量呈逐年显著增加趋势，钾肥最佳施用量有所上升，磷肥最佳施用量缓慢增加。