地震仪

People laughed at Zhang Heng when he first introduced his seismograph and it was only later that the world recognized his greatness .

张衡最初介绍他的地震仪时，人们还嘲笑他呢，只有在后来世界才承认他的伟大。

But since the innate modern seismograph＇s hundred years.

但自有近代地震仪的百年以来。

The seismograph reported 300 quakes for the period of 1905-1907 alone.

地震仪仅在1905至1907年期间便报告了300次震动。

Curie point isotherm is the temperature isotherm where ferromagnetic minerals in the rocks change from ferromagnetism into paramagnetism because the temperature increases to the Curie point. Below this isotherm, the rocks are thought to be almost non-magnetism because their temperature is higher than the Curie point. Sino-US two-ship expanding spread profiles eastern transect in 1985 and Sino-Japan Ocean Bottom Seismography profile in 1993 (OBS93) crossed the major structural belts and basins in the northeastern South China Sea.

居里面是岩石中铁磁性矿物因温度升高达到居里点而由铁磁性变为顺磁性时的温度界面，在这个面以下的岩石由于温度超过居里点而被认为几乎无磁性。1985年中美双船地震扩展排列东剖面和1993年中日合作海底地震仪剖面(OBS93)均穿越南海东北部各主要构造带和盆地，获得了完整的地震及重、磁资料。

The ground motion at each seismometer is amplified and recorded electronically at a central recording site.

每个地震仪的运动都被电子扩大并记录在记录中心。

They would have been taught, and proudly, that almost 2,000 years ago an astronomer named Chang Heng invented the world's first seismoscope.

他们应该被骄傲地告知，大约在2000年前，一位叫张衡的天文学家发明了世界上第一个地震仪。

When the drawing board rotates it makes direct contact with the earth itself, but paper can only contact with the earth loosely through the drawing board. The seismoscope works according to this principle.

四线摆在运动时画笔直接与地球本身相连，而纸只是通过四根摆线松散的与地球相连，地震仪就是用这种原理工作的。

In terms of the documentation frequency of these historical data on earthquakes of 4.7 magnitude or above in the past 3000 years ( Table 5 ) the frequency was below 2 times per 10 years for most of the time before the Song Dynasty; when printing was invented in the Song Dynasty the frequency increased to 3 times per 10 years; after the invention of seismoscope in 1900 it reached 100-1000 times per 10 years.

从3000年来4.7级以上的(ji2 yi3 shang4 de0)历史地震的史料记录频度看（图5），宋朝以前的绝大部分时间都在（2次/10年）以下；宋朝出现了印刷术，记录频度增到（3次/ 10年）以上；1900年后现代地震仪问世，记录频度达到（100-1000次/10年）的高水平。

So we designed a adaptive synchronizing controller based on hereinbefore hardware environment: first a small magnitude reference signal r is outputted to system through the signal card (to ensure that the vibrating system works in a linear state), and this signal is sent to the moving coil of vibrator through the power amplifier, so vibration is produced through electromagnetic induction. Secondly the vibration signal can feedback to the data acquiring card in the servo system through the acceleration sensor on the Vibroseis reactor M〓 and the base-plate M〓, then the computer can get the current vibrating state y〓 of the coil of vibrator according to the feedback information from the data acquiring card, and give a real time comparing between the current state y〓 and the reference output y〓 of the set-in reference model with current reference input being r , then regulates the correlative controlling parameters according to the error e〓=y〓-y〓 till y〓→y〓, finally normal signal sweeping begins with a certain phase fixed. Meanwhile a synchronization signal for seismic signal record is sent to seismograph from synchronization signal outputting component in the Vibroseis system to perform the controlling process of synchronization of sweeping phases.

为此，我们基于以上的硬件环境设计了一个自适应同步控制器：首先通过信号发生卡对系统输出小幅度的参考信号r(从而保证振动系统工作处于线性状态)，信号通过前置放大器、功率放大器等送到激震器动圈，并通过电磁感应产生振动，振动信号通过可控震源激震器反应块M〓和基板M〓上的加速度传感器反馈给伺服系统中的数据采集卡，工控计算机根据采集卡的反馈信息，获取当前激震器动圈的振动状态y〓，并实时地将该状态与内置的参考模型在当前参考输入r下的参考输出y〓进行辨识，再将两者输出误差e〓＝y〓-y〓对系统的有关控制参数进行调整，直至y〓→y〓，最后在经过某一固定的相位后，开始信号的正常扫描过程，与此同时，由可控震源系统的同步信号输出部件向地震仪送出一地震信号记录同步信号，进而完成扫描相位同步控制过程。

It is specially pointed Out that the comb filter has the property of preserving spectral shape of noise from Σ－△A/D moodulation.

给出了梳状滤波器的设计方法，作为一个例子对地震仪中广泛采用的Σ－△A／D转换器CS5324中的梳妆滤波器进行了分析说明。

Since historical times,England ,where the early inhabitants were Celts, has been conquered three times .

从有历史以来，英国，在此地早期居住的是凯尔特人，已经被征服了三次。

Bluetooth OBEX File Transfer Enables the sending and receiving of files on your phone via Bluetooth.

蓝牙OBEX文件移动允许经过蓝牙传送和接受文件。。。。