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Users can take their ecg instantly by pressing two fingers on the side of the phone for 30 seconds .

而要获得心电图，用户只需要将2根手指按住手机侧面30秒钟即可。

So with more research , it may be that gps could use the ecg to identify women who are at hidden risk of heart disease and stroke .

因此，随着研究的逐步深入，或许普通医生也可以利用心电图来辨别哪些妇女具有患心脏病和中风的潜在可能性。

But devices like ecg machines are expensive , hard to find and require expertise - especially in the developing world .

但类似于心电图机的仪器是十分昂贵的，而且对于普通人他很难使用也不易找到在发展中国家尤其如此。

As a proof of concept , lin 's system currently takes the user 's ecg reading from each palm once , and a key based on that reading is stored and used for all later decryptions .

作为此想法的佐证，林先生的系统目前从使用者的左右手掌各读取心电图一次，基于此存储一个密钥用于后续的所有解密。

The devices were small and relatively inexpensive and they were originally " developed for markets in emerging economies ( the ecg device for rural india and the ultrasound machine for rural china ) and are now being sold in the us " .

这些设备体型小、价格相对不贵，起初“是为发展中经济体的市场而研发的（心电图仪是为印度农村开发，而超声波仪是为中国农村开发），如今都在美国销售”。