Surgical Continuum Manipulator Control Using Multiagent Team Deep Q Learning.

Continuum manipulator has shown great potential in surgical applications. The flexibility of the continuum manipulator helps it achieve many complicated surgeries, such as neurosurgery, vascular surgery, abdominal surgery, etc. In this paper, we propose a Team Deep Q learning framework (TDQN) to control a 2-DoF surgical continuum manipulator with four cables, where two cables in a pair form one agent. During the learning process, each agent shares state and reward information with the other one, which namely is centralized learning. Using the shared information, TDQN shows better targeting accuracy than multiagent deep Q learning (MADQN) by verifying on a 2-DoF cable-driven surgical continuum manipulator. The root mean square error during tracking with and without disturbance are 0.82mm and 0.16mm respectively using TDQN, whereas 1.52mm and 0.98mm using MADQN respectively.Clinical Relevance-The proposed TDQN shows a promising future in improving control accuracy under disturbance and maneuverability in robotic-assisted endoscopic surgery.

Improvement in near-infrared absorbance attenuation by using nanometer black silicon composited with gold nanoparticles.

In order to solve the problem of near-infrared (NIR) absorbance attenuation of silicon, a method of preparing gold nanoparticles (AuNPs) on the micro-nano-structured black silicon (B-Si) is proposed. In this study, the local surface plasmon resonance (LSPR) of AuNPs excited by a light field is used to achieve B-Si materials with broad spectrum and high absorption. The results show that nanometer B-Si composited with 25-nm AuNPs has an average absorption of 98.6% in the spectral range of 400-1100 nm and 97.8% in the spectral range of 1100-2500 nm. Compared with ordinary B-Si, the absorption spectrum is broadened from 400-1100 nm to 400-2500 nm, and the absorption is increased from 90.1 to 97.8% at 1100-2500 nm. It is possible to use the B-Si materials in the field of NIR-enhanced photoelectric detection and micro-optical night vision imaging due to the low cost, high compatibility, and reliability.

A Dual Four-Quadrant Photodetector Based on Near-Infrared Enhanced Nanometer Black Silicon.

In this paper, a new preparation process of nanometer black silicon is proposed, by which high trapping optical Se-doped black silicon material is prepared by nanosecond pulsed laser ablation of high-resistance silicon coated with Se film in HF gas atmosphere. The results indicate that the average absorptivity of 400-2200 nm band before annealing is 96.81%, and the absorptivity maintains at 81.28% after annealing at 600 degrees. Meanwhile, black silicon prepared under the new technology is used in double four-quadrant photodetector, the results show that, at a reversed bias of 50 V, the average unit responsiveness is 0.528 A/W at 1060 nm and 0.102 A/W at 1180 nm, and the average dark current is 2 nA at inner quadrants and 8 nA at outer quadrants. The dual four-quadrant photodetector based on near-infrared enhanced black silicon has the advantages of high responsiveness, low dark current, fast response and low crosstalk, hence it is appropriate for a series of direction of applications, such as night vision detection and medical field.