瞬变时间

This paper analyzed thoroughly the transient electromagnetic field analytic expression in homogeneous half space, discovered that the transient response curve has a characteristic of translational expansion and contraction with the underground conductivity, transmit loop length and observation time. According to that, we proposed a new direct method to calculate full time domain apparent resistivity.

深入分析了均匀半空间中瞬变电磁场的解析表达式，发现瞬变响应曲线随地下电导率、发射回线边长与观测时间具有平移伸缩特性，并据此提出了一种新的直接计算全区视电阻率的方法。

Three expert systems for inversion were applied into practical engineering. Basing on the formulation of apparent resistivity in whole space, the curves of time vs. response which were gotten from practical exploring were transformed into the curves of depth vs. apparent resistivity by VC program. The data which were gotten from measurement line on working face in tunnel were transformed into the section map of depth vs. apparent resistivity. The result shows that expert system for inversion is feasible.

将三种反演专家系统应用于实际工程中，同时根据全空间视电阻率公式，采用VC编程的方法，将实际工程探测所得到的时间——响应曲线转化为深度——视电阻率曲线，将掌子面测线数据转化为深度——视电阻率断面图，对比两种计算方法的结果，说明反演专家系统在瞬变电磁反演中的可行性

Decaying with time, especially as a simple ''.

瞬变的随时间延续而衰减的，尤指作为时间的一个简单的''。

Physics Decaying with time, especially as a simple exponential function of time.

瞬变的：随时间延续而衰减的，尤指作为时间的一个简单的指数函数

The results show that, 3D Dufort-Frankel method is unconditional stable; the diffusion velocity of transient field is related to sample interval and resistivity contrast.

结果表明：三维DuFort-Frankel差分算法是无条件稳定的，瞬变电磁场的扩散速度与采样时间间隔和电阻率差异有关。

In order to analyze and correct this effect, the method to calculate turn-off time is given. According to theoretical TEM response of multiturn loop source, TEM response affected by linear and half-sine turn-off current was calculated, and Taylor's series expansion was used by calculating TEM response of half-sine turn-off current. The two mode's responses, linear mode's response and half-sine mode's response, were analyzed in turn-off time 2μs-100μs.

为了分析和校正这种影响，文中给出了关断时间的计算方法，根据多匝回线源产生的瞬变场理论解析式，计算了线性和半正弦关断电流影响下瞬变场表达式，计算半正弦关断电流产生的瞬变场时将正弦函数进行泰勒展开；分析了关断时间在2 μs~100 μs之间两种关断模式产生的瞬变响应。

Numerical method for calculating the exact all-time apparent resistivity for time domain transient electromagnetic method is proposed in this paper.

bstract 给出了一种时间域瞬变电磁法视电阻率的数值计算方法，利用该方法可以容易地求出中心方式的全程视电阻率。

A numerical method for calculating the exact all-time apparent resistivity for time domain transient electromagnetic method is proposed in this paper.

给出了一种时间域瞬变电磁法视电阻率的数值计算方法，利用该方法可以容易地求出中心方式的全程视电阻率。

A numerical method for calculating the exact alltime apparent resistivity for time domain transient electromagnetic method is proposed in this paper.

给出了一种时间域瞬变电磁法视电阻率的数值计算方法，利用该方法可以容易地求出中心方式的全程视电阻率。

A seven-node difference scheme of the diffusion equation was proposed to study the behaviors of transient electromagnetic field in complicated 3-D geoelectric body. Models of roadway and anomaly body were set up for simulating the transient field excited by a vertical magnetic dipole source. The result of numerical simulation shows that the presence of low resistive conductor leads to noticeable distortion of isolines for the "smoke ring" field, whereas the distortion is not so obvious where the roadway and the poor conductor are located.

为了探讨复杂三维地电体中瞬变电磁场的响应特征，推导了三维扩散方程的七点差分格式，建立了巷道和异常体模型，并对垂直磁偶源激发的瞬变场进行了数值模拟，观察到早期&烟圈&场在低阻体处等值线发生的明显畸变，在巷道和高阻体处的畸变较弱，随着时间的增加异常体的影响逐渐减弱。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了