60 research outputs found
Fig. 2 in Alkaloids from the stem barks of Erythrina stricta
No full textFig. 2. The experimental and calculated ECD spectra of 15 and 18 in CH3OH(left: 15; right: 18).Published as part of Li, Fengqiu, Bi, Dewen, Liang, Xuesong, Luo, Ruilong, Zhuang, Hongdan & Wang, Liqin, 2020, Alkaloids from the stem barks of Erythrina stricta, pp. 1-6 in Phytochemistry (112220) 170 on page 4, DOI: 10.1016/j.phytochem.2019.112220, http://zenodo.org/record/829297
Fig. 3 in Alkaloids from the stem barks of Erythrina stricta
No full textFig. 3. Hypothetical biogenetic pathways of compounds 16–19.Published as part of Li, Fengqiu, Bi, Dewen, Liang, Xuesong, Luo, Ruilong, Zhuang, Hongdan & Wang, Liqin, 2020, Alkaloids from the stem barks of Erythrina stricta, pp. 1-6 in Phytochemistry (112220) 170 on page 4, DOI: 10.1016/j.phytochem.2019.112220, http://zenodo.org/record/829297
Hydrodynamic Analysis of Flow Stabilization Process in a Miniature Circulating Water Channel Equipped with Combined Porous Plate Structures
No full textAs a foundational platform for fluid dynamics research on underwater devices, the quality of stable and uniform incoming flow in a circulating water channel (CWC) is essential. Due to the inherent structural characteristics of porous media, their application has become widespread in offshore and marine engineering. This study presents the design of a miniature circulating water channel, alongside the development of a computational fluid dynamics (CFD) numerical model to simulate the interaction between porous media and incoming flow. By analyzing the pressure loss of fluid within the porous plates and incorporating it as a source term in the momentum equation, heavy computational costs associated with fine mesh requirements in micro porous models were avoided. Simulations were conducted to investigate the effects of combined porous plates on the flow field, and the porous media model was validated by comparisons with experimental data. The distribution of the flow field within the channel was analyzed to define the test section, which was conducive to further structural optimization. The results indicated that the combined porous plates stabilized the flow field of the CWC, and, following structural optimization, the occurrence of backflow was reduced, thereby expanding the effective test section range
Interactions of New Synthesized Fluorescent Cationic Amphiphiles Bearing Pyrene Hydrophobe with Plasmid DNA: Binding Affinities, Aggregation and Intracellular Uptake
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Surface damage of single-crystal diamond (100) processed based on a sol-gel polishing tool
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Stable and Fast Planar Jumping Control Design for a Compliant One-Legged Robot
No full textCompliant bipedal robots demonstrate a potential for impact resistance and high energy efficiency through the introduction of compliant elements. However, it also adds to the difficulty of stable control of the robot. To motivate the control strategies of compliant bipedal robots, this work presents an improved control strategy for the stable and fast planar jumping of a compliant one-legged robot designed by the authors, which utilizes the concept of the virtual pendulum. The robot was modeled as an extended spring-loaded inverted pendulum (SLIP) model with non-negligible torso inertia, leg inertia, and leg damping. To enable the robot to jump forward stably, a foot placement method was adopted, where due to the asymmetric feature of the extended SLIP model, a variable time coefficient and an integral term with respect to the forward speed tracking error were introduced to the method to accurately track a given forward speed. An energy-based leg rest length regulation method was used to compensate for the energy dissipation due to leg damping, where an integral term, regarding jumping height tracking error, was introduced to accurately track a given jumping height. Numerical simulations were conducted to validate the effectiveness of the proposed control strategy. Results show that stable and fast jumping of compliant one-legged robots could be achieved, and the desired forward speed and jumping height could also be accurately tracked. In addition to that, using the proposed control strategy, the robust jumping performance of the robot could be observed in the presence of disturbances from state variables or uneven terrain
A Prototype Design and Sea Trials of an 11,000 m Autonomous and Remotely-Operated Vehicle Dream Chaser
No full textTo better study the biology and ecology of hadal trenches for marine scientists, the Hadal Science and Technology Research Center (HAST) of Shanghai Ocean University proposed to construct a movable laboratory that includes a mothership, several full-ocean-depth (FOD) submersibles, and FOD landers to obtain samples in the hadal trenches. Among these vehicles, the project of an FOD autonomous and remotely-operated vehicle (ARV) named “Dream Chaser” was started in July 2018. The ARV could work in both remotely-operated and autonomous-operated modes, and serves large-range underwater observation, on-site sampling, surveying, mapping, etc. This paper proposed a novel three-body design of the FOD ARV. A detailed illustration of the whole system design method is provided. Numerical simulations and experimental tests for various sub-systems and disciplines have been conducted, such as resistance analysis using the computational fluid mechanics method and structural strength analysis for FOD hydrostatic pressure using the finite element method and pressure chamber tests. In addition, components tests and the entire system tests have been performed on land, underwater, and in the pressure chamber in the laboratory of HAST, and the results are discussed. Extensive experiments of two critical components, i.e., the thrusters and ballast-abandoning system, have been conducted and further analyzed in this paper. Finally, the procedures and results of lake trials, South China Sea trials and the first phase of Mariana Trench sea trials of the ARV in 2020 are also introduced. This paper provides a design method for the novel three-body FOD ARV. More importantly, the lessons learned from the FOD pressure test, lake tests, and sea trials, no matter the success or failure, will guide future endeavors and the application of ARV Dream Chaser and underwater vehicles of this kind
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