为植入医疗设备提供权力是一个主要挑战。明显的方法，例如使用可充电电池或超级电容器以及“无线”充电，甚至是外部电线，除了尺寸外，还有各种问题。使用RF能量，超声或磁场的无线充电带来了由于吸收，局部局部加热，换能器的大小和可靠性而引起的效率低下问题。
Now, in research supported by the National Science Foundation and the National Institutes of Health, a team at Rice University developed what they say is the first energy-capture and conversion device driven by external magnetic fields in a manner that’s largely unattenuated by the body-tissue mass. They tested it by implanting it along with needed drive circuitry into a rodent’s brain to invoke various types of neural stimulation. Different waveforms and patterns of such stimulation are already used to treat or reduce conditions such as Parkinson’s disease, depression, pain, and obsessive-compulsive disorders.
磁力传输是一种已被使用的技术，但在临床“高频”中不起作用范围超过50 Hz。神经工程计划项目可实现微型磁性神经刺激剂，可直至临床相关的高频。该项目的结果是将磁能捕获/转化率和刺激电子设备的组合结合在一起（图。1）（我们还将跳过他们的生活和生活如何）。
The power-transfer technique avoids the issues of absorption by the body or differences in impedance at interfaces between air, bone, and tissue associated with use of RF, ultrasound, light, and even magnetic coils. These have been evaluated in other projects and products for powering tiny wireless implants, but they have difficulties due to living tissue acting as a path impediment or producing harmful amounts of heat.
紧密整合的水稻项目具有两个电子方面：功率传感器和源函数以及神经刺激电子产品。我们将重点介绍在此处的前一个功能，并绕过神经刺激本身的复杂生理主题，这些刺激模式会影响哪些疾病及其实际基于啮齿动物的临床测试。他们非常详细且高度可读的论文”磁电材料在治疗频率下的微型，无线神经刺激涵盖了所有这些，以及对替代权力转移技术提出的挑战的有趣的前期解释（发表在Neuron但在付费墙后面；幸运的是，相同的预印已发布）。
The power-transfer arrangement merges two diverse physical phenomena: the magnetostrictive effect and the piezoelectric effect to transform a magnetic field to an electric field and voltage. Rather than use an implanted coil, they employed a material that generates a voltage via mechanical coupling between magnetostrictive and piezoelectric layers in a thin film. The imposed varying magnetic field creates strain in the magnetostrictive layer as the magnetic dipoles align with the applied field. That strain, in turn, exerts a force on the piezoelectric layer, which generates a voltage. The combined magnetoelectronics (ME) don’t suffer from the same miniaturization issues that affect coils and can be driven by weak magnetic fields on the order of a few millitesla（图2）。
To further improve energy-transfer efficiency, a constant-bias field with a permanent magnet or an electromagnet was applied. Since the strain in the magnetostrictive material is a sigmoidal function of the magnetic-field strength, the change in voltage produced by the alternating field is largest when the field oscillates about the midpoint of the sigmoid（图3）。
该偏置场在S形磁刻度响应曲线附近产生磁场的抵消，并在应用Millitesla交替磁场时产生有用的电压水平。他们使用电磁线圈和定制电路来控制交替磁场的频率和时机(Fig. 4)。
尽管该项目的功率“侧”是一项重大努力，但它与刺激器和电子部分密切相关。纸质合着者兼神经工程计划成员Caleb Kemere与应用物理学学生Amanda Singer一起领导了这项工作，此外还有一个大型项目团队（如本文作者列表所示）。总体而言，该项目花费了五年以上，主要是因为辛格必须“从头开始”几乎将所有内容都进行，并且还必须进行临床测试。
正如凯梅尔（Kemere）所解释的那样，“这种电力转移技术没有基础设施。如果您使用的是射频（RF），则可以购买RF天线和RF信号发电机。如果您使用的是超声波检查，那就不像有人说：“哦，顺便说一句，首先必须构建超声波机。”
He noted that “Amanda had to build the entire system, from the device that generates the magnetic field to the layered films that convert the magnetic field into voltage and the circuit elements that modulate that and turn it into something that’s clinically useful. She had to fabricate all of it, package it, put it in an animal, create the test environments and fixtures for the in vivo experiments, and perform those experiments. Aside from the magnetostrictive foil and the piezoelectric crystals, there wasn’t anything in this project that could be purchased from a vendor.”
