Chaos-assisted broadband momentum transformation in optical microresonators

The law of momentum conservation rules out many desired processes in optical microresonators. We report broadband momentum transformations of light in asymmetric whispering gallery microresonators. Assisted by chaotic motions, broadband light can travel between optical modes with different angular momenta within a few picoseconds. Efficient coupling from visible to near-infrared bands is demonstrated between a nanowaveguide and whispering gallery modes with quality factors exceeding 10 million. The broadband momentum transformation enhances the device conversion efficiency of the third-harmonic generation by greater than three orders of magnitude over the conventional evanescent-wave coupling. The observed broadband and fast momentum transformation could promote applications such as multicolor lasers, broadband memories, and multiwavelength optical networks

Utilization of soybean curd residue for polysaccharides by Wolfiporia extensa (Peck) Ginns and the antioxidant activities in vitro

To reduce nutrient cost and improve the production of polysaccharides by Wolfiporia extensa (Peck) Ginns (F.A. Wolf), soybean curd residue (SCR), a food waste, was chosen as the nutrient source in this study. The objective of this research is to determine optimum culture conditions for solid state fermentative production of polysaccharides and evaluate the antioxidant activities. Response surface methodology (RSM) was employed to optimize the fermentation conditions of F.A. Wolf for the enhancement of polysaccharides. The optimal conditions were obtained by response surface methodology as follows: fermentation temperature 23.7 °C, fermentation time 7.5 days, and inoculum size 15.5 mL. Under optimized conditions, the polysaccharides yield reached 88.93 ± 1.87 mg/g, which was in close agreement with values predicted by the mathematical models. Furthermore, the polysaccharides exhibited positive antioxidant activities. This research provides references for the large-scale production of polysaccharides by F.A. Wolf and points to a new direction for SCR utilization

Dynamic Trajectory Planning for Automated Lane Changing Using the Quintic Polynomial Curve

As one of the key algorithms in supporting AV (autonomous vehicle) to complete the LC (lane changing) maneuver, the LTP (LC trajectory planning) algorithm generates safe and efficient LC trajectory for the AV. This paper proposes a novel dynamic LTP algorithm based on the quintic polynomial curve. This algorithm is capable of adjusting LC trajectory according to the state changes of the surrounding driving environment. The formulation of our proposed algorithm mainly consists the underlying form of trajectory equation, the optimization objective function, the corresponding constrains, and the SQP (sequential quadratic programming) algorithm. For each planning step, the time-based quintic polynomial function is introduced to model the trajectory equation. The problem of solving the parameters of the corresponding equation is then transformed into an optimization problem, which takes driver’s safety, comfort, and efficiency into account. After that, the SQP algorithm is employed to solve this optimization problem. Finally, both numerical simulation and field-data validation are used to verify the effectiveness of our proposed algorithm. We anticipate that the research could provide certain valuable insights for developing more reliable LC algorithms for AVs

Method for Quantitative Study of Airway Functional Microanatomy Using Micro-Optical Coherence Tomography

We demonstrate the use of a high resolution form of optical coherence tomography, termed micro-OCT (μOCT), for investigating the functional microanatomy of airway epithelia. μOCT captures several key parameters governing the function of the airway surface (airway surface liquid depth, periciliary liquid depth, ciliary function including beat frequency, and mucociliary transport rate) from the same series of images and without exogenous particles or labels, enabling non-invasive study of dynamic phenomena. Additionally, the high resolution of μOCT reveals distinguishable phases of the ciliary stroke pattern and glandular extrusion. Images and functional measurements from primary human bronchial epithelial cell cultures and excised tissue are presented and compared with measurements using existing gold standard methods. Active secretion from mucus glands in tissue, a key parameter of epithelial function, was also observed and quantified