Optical imaging techniques provide low-cost, non-radiative images with high spatiotemporal resolution, making them advantageous for long-term dynamic observation of blood perfusion in stroke research and other brain studies compared to non-optical methods. However, high-resolution imaging in optical microscopy fundamentally requires a tight optical focus, and thus a limited depth of field (DOF). Consequently, large-scale, non-stitched, high-resolution images of curved surfaces, like brains, are difficult to acquire without z-axis scanning. To overcome this limitation, we developed a needle-shaped beam optical coherence tomography angiography (NB-OCTA) system, and for the first time, achieved a volumetric resolution of less than 8 μm in a non-stitched volume space of 6.4 mm × 4 mm × 620 μm in vivo. This system captures the distribution of blood vessels at 3.4-times larger depths than normal OCTA equipped with a Gaussian beam (GB-OCTA). We then employed NB-OCTA to perform long-term observation of cortical blood perfusion after stroke in vivo, and quantitatively analyzed the vessel area density (VAD) and the diameters of representative vessels in different regions over 10 days, revealing different spatiotemporal dynamics in the acute, sub-acute and chronic phase of post-ischemic revascularization. Benefiting from our NB-OCTA, we revealed that the recovery process is not only the result of spontaneous reperfusion, but also the formation of new vessels. This study provides visual and mechanistic insights into strokes and helps to deepen our understanding of the spontaneous response of brain after stroke.

相比传统电生理方法,基于光遗传学的神经调控技术具有低侵入性、可结合基因工程实现特定神经元选择性激发等优势,近年来在脑科学研究领域得到广泛应用。对基于光遗传学的神经调控方法进行了系统回顾,详细介绍了双光子光遗传技术及其在在体高空间分辨率神经调控方面的研究进展,包括串行螺旋扫描激发、串行扩展光斑扫描激发以及基于广义相衬和计算机生成全息图的并行激发技术等。此外,还讨论了目前双光子光遗传技术在激发精度及激发视场等方面存在的问题及解决方案,并指出将双光子成像与双光子光遗传结合的全光电生理技术可实现神经活动的同步观测与调控,进而极大地推动神经环路解析等神经科学研究。

借鉴阻尼谐振子正则量子化的方法,实现了对耗散介观RLC串并联电路的量子化,并 在此基础上,研究了真空态下电路中电荷和自感磁通链、电压和电流的量子涨落。结果表明,电路 中电荷和自感磁通链、电压和电流在真空态下都具有各自的量子涨落,且量子涨落及量子涨落积的 大小皆与电路中的器件参数有关,并随时间按指数规律衰减。

随着短距离通信网的不断发展,多模光纤(MMF)已经成为实现高速大容量信息传输的理想介质,但多模光纤严重的模式色散限制了其传输能力。为了提高多模光纤的传输能力,设计了基于自适应调制(AM)的正交频分复用(OFDM)多模光纤通信系统。提出了适用于该系统的自适应比特分配算法,并通过仿真证明了该算法的有效性。在此基础上重点分析了自适应调制对系统性能的影响,对比了自适应前后不同传输速率、不同信道情况下的误码特性。结果表明,自适应调制能较好地克服深衰落点对系统性能的影响,有效降低了系统误码率(BER)。