条件表达式

Firstly, The sufficient con-ditions of the existence and uniquity of the positive equlibria by applying functional derivative isobtained; Secondly, the global attractability of the positive equlibria is investigated by charateristicroots theory and oscillation theory; Thirdly, regarding the delay as a parameter, conditions of theexistence of Hopf bifurcation and the peridic solution, furthermore, the form of the approximateperidic solution are obtained; Finally, Some specific examples are given and the solution diagrameappears by Matlab.

首先利用导数性质，得到了该模型正平衡态存在惟一性的充分条件；其次，利用特征值和振动性理论得到了该模型正平衡态全局渐近稳定性充分条件；然后，应用Hopf分支理论证明了该模型Hopf分支及近似分支周期解的存在性，并给出了周期解的近似表达式；最后，借助于MATLAB数学软件，举例并绘出了模型数值解的拟合图象，验证了文中定理条件的可行性。

Second, we rewrite the simple path expression into SQL statements. We research the different rewriting techniques for the different mapping nodes and different condition in where clause. For the query optimizing, we propose the path index based on the notion of node equivalence which is computed by bi-simulation algorithm.

第二步把简单路径表达式通过DTD字典重写为SQL语句，主要研究了对于SPE上的结点由于其映射的结点类型不同而进行不同的重写处理，同时研究了对于带有条件的查询在各种情况下的重写过程（如返回路径和条件路径不在一条路径上、多条件查询等）。

For example, the conditional operator is often used to print one or another value, depending on the result of a condition. Incompletely parenthesized uses of the conditional operator in an output expression can have surprising results

例如，经常使用条件操作符根据一定的条件输出一个或另一个值，在输出表达式中，如果不严格使用圆括号将条件操作符括起来，将会得到意外的结果

The theory of high-strain dynamic testing of pile bearing capacity. The basic calculation expression of pile high-strain dynamic testing is rederived in a simple way, especially the semi-empirical analytical expression of wave equation . Besides, theoretically it has been proved that it's not necessary to have identic section hypotaxis along pile, and the application condition and reasonable operation have been pointed out. the CASE comprehensive method is suggested to replace the traditional CASE method. author has made a lot of improvement for the mathematical model of the matching analysis measured curves in the business software CCWAPC and scientific research software JXWAPC of which the author is in charge.

关于高应变动力试桩法的理论研究以简明方式重新推导了高应变动力试桩法基本计算表达式，尤其波动方程半经验解析表达式，同时从理论上证明了CASE法并不需要桩身等截面假设，亦指出了该方法的适用条件及合理使用办法，并建议利用CASE综合分析法取代传统的CASE分析法；作者在其负责编制的商业软件CCWAPC及科研软件JXWAPC中，对波动方程拟合分析法数理模型进行了一系列重大改进，考虑了灌注桩桩周土体的变形特性和动荷截作用下的非线性效应、大直径桩的横向惯性效应。

The effects of the linear birefringence and incident polarizing angle upon the performance of a bulk glass optical current sensor are derived and analyzed, a modulation formula to describe the influences of the linear birefringence to the output signal of the sensor is given.The effect of the incident polarizing angle upon the performance of the system and the condition to determine if or not it can exert the influence are also given.

对线性双折射及入射起偏角对光学玻璃电流传感器输出特性的影响进行了理论推导与分析，给出了光学玻璃电流传感器在非理想状态下线性双折射对输出电压的调制函数的数学表达式，并给出了入射起偏角对系统影响的数学表达式及其对系统有无影响的条件。

Several models are advanced in this dissertation, such as precision model with Kepler orbit and approximate models with conditions in the proper order of small orbital noncoplanarity, small eccentricity, short distance, short running time and equal orbital semimajor axis.

采用逐步递进的方式，推导了一系列对应Kepler轨道的精确表达式和对应小轨道非共面度、小轨道偏心率、近距离、短时间、相等的轨道半长轴等条件的近似表达式，以适合各种情形下对航天器相对轨道运动的描述。

Based on the Mie scattering theory, a formula to calculate the scattered light flux in a certain solid angle under the condition of polarized light input is derived form the formula for calculating scattered light intensity. The results are compared with the condition illuminated by a unpolarized light.

在Mie散射理论基础上，由单分散射的光强表达式导出在偏振光的入射条件下一定立体角内的散射光通量的表达式，并与自然光入射作比较。

In the research on the backward-wave oscillation suppression the startoscillation current which is derived from Two-wave theory approximately is given up. Four typical un-uniform slow wave structures start-oscillation current equations are derived by backward-wave amplifing gain expressions with the Two-wave theory. Then the start-oscillation current rates I〓/I〓 between ununiform circuit and uniform circuit of the four structures have been got.

在返波抑制问题的研究中，从二波理论出发，抛弃了二波理论中从起振条件出发来得到起振电流近似表达式的方法，而是利用二波理论的基本关系式分别推导出了四种典型实用的非均匀输出线路的返波增益表达式，采用计算返波增益的方法来得到四种非均匀输出线路的起振电流与均匀输出线路起振电流的比值I〓/I〓。

Language righteousness checked without any error, we can get table name and the corresponding fields names. The paper adopts the stack to realize calculating the logic expressions type. Through the value of the logic expressions, we can check whether conditions in the QL establish or not.

语义检查无误后，经分析可以得到表名和相应的列名，用栈来实现布尔表达式的求值等，布尔表达式的计算结果，用以检查条件是否成立，为事务处理提供函数接口，以便进行正确的查询。

Language righteousness checked without any error, we can get table name and the corresponding fields names. The paper adopts the stack to realize calculating the logic expressions type. Through the value of the logic expressions, we can check whether conditions in the QL establish or not. And we pass the result to the tranction disposal layer which can deal with the right search.

语义检查无误后，经分析可以得到表名和相应的列名，用栈来实现布尔表达式的求值等，布尔表达式的计算结果，用以检查条件是否成立，为事务处理提供函数接口，以便进行正确的查询。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。