300 publications from this institution
In this paper, the chemical constituents of voltile oils from Geranium wlassowianum were analyzed by GC-MS. 24 constituents in the oils were identified (75.42% of total oil), saturated alkanes of them are main components.
Due to stricter municipal wastewater discharge standards, there is an increased need for further treatment of nitrate in the secondary effluent of wastewater treatment plants. This is achieved through denitrification by the addition of external carbon sources, which leads to increased costs in wastewater treatment. The aim of this study was to examine the possibility of simultaneous removal of nitrate and phosphorus from simulated secondary effluent by employing a sponge-iron-based denitrifying filter at room temperature. The results indicate that at hydraulic retention times of over 2 h, more than 60% of the nitrate was reduced to ammonia and nitrite via iron-based abiotic nitrate reduction. However, sponge iron easily scaled after two months of operation. Therefore, a little glucose was added to the influent, resulting in a final COD/N ratio of 1:1. Mixotrophic nitrate reduction was observed, and the rust of sponge iron was successfully dissolved. Batch test results demonstrate that biological nitrate denitrification accounted for 70.0% of the total nitrate reduction. Additionally, high-efficiency phosphorus removal through the chemical reaction of released iron and phosphorus was achieved throughout the entire experiment, with removal efficiencies of more than 90% at hydraulic retention times of over 2 h. Moreover, high-throughput sequencing data show that the species diversity obviously increased after adding organic carbon, suggesting the coexistence of heterotrophic and autotrophic denitrifiers. Hence, the sponge-iron denitrifying filter has considerable prospects in the field of secondary effluent treatment and is likely to be the future direction of zero-valent iron application in sewage treatment.
The investigation of indigenous wine yeast can facilitate the production of distinctive Beijing wine by providing wineries with more choices in distinctive wine yeasts. Wine yeasts that were isolated from grape must during spontaneous fermentation and from vineyard soil were preliminarily classified by their colony morphologies when cultured on Wallerstein Laboratory Nutrient (WLN) medium and then were identified by 5.8S ITS sequence analysis. Four selected strains were involved in inoculated fermentation tests. The results showed that five yeast species were isolated from the grape must, and five non‐ Saccharomyces yeast species were found in vineyard soil. The colony morphology of Pichia occidentalis on the WLN medium was described herein for the first time. An effective way which could be used for isolate and select wine yeasts from soil samples on WLN medium was described. And one of the selected indigenous strains shared over 99% similarity on 5.8S ITS sequence with commercial wine yeast, which indicated that commercial yeast might have influenced the local yeast diversity. The two selected indigenous Saccharomyces cerevisiae strains, which showed good fermentation performances, could be applied in the local wine industry in the future.
<abstract><p>We investigate a new cross-diffusive prey-predator system which considers prey refuge and fear effect, where predator cannibalism is also considered. The prey and predator that partially depends on the prey are followed by Holling type-Ⅱ terms. We first establish sufficient conditions for persistence of the system, the global stability of constant steady states are also investigated. Then, we investigate the Hopf bifurcation of ordinary differential system, and Turing instability driven by self-diffusion and cross-diffusion. We have found that the $ d_{12} $ can suppress the formation of Turing instability, while the $ d_{21} $ promotes the appearance of the pattern formation. In addition, we also discuss the existence and nonexistence of nonconstant positive steady state by Leray-Schauder degree theory. Finally, we provide the following discretization reaction-diffusion equations and present some numerical simulations to illustrate analytical results, which show that the establishment of prey refuge can effectively protect the growth of prey.</p></abstract>
This study focuses on the static output feedback control of nonlinear Markov jump singularly perturbed systems within the framework of Takagi–Sugeno fuzzy approximation. From a practical point of view, the phenomenon of asynchronous switching between the plant and the controller is considered and characterized by a finite piecewise‐homogenous Markov process. Particularly, for facilitating the controller synthesis, the closed‐loop system is transformed into a fuzzy Markov jump singularly perturbed descriptor system by adopting descriptor representation. In order to fully accommodate the system features, an appropriate stochastic Lyapunov function is constructed. Afterwards, by combining Finsler’s lemma, the mean square exponential admissibility of the system is analyzed. The conditions ensuring the existence of the predesigned controller are given and further solved by designing a brief search algorithm. Finally, a typical circuit system is used to demonstrate the application potential of the developed control technology and the effectiveness of the control strategy.
In order to study the operation of planetary gear transmission, the article takes the two-stage planetary gear transmission system as the research object to determine the correct meshing parameters between the sun gear, planetary gears and internal gears. With the help of a plug-in in SolidWorks, a three-dimensional planetary gear is carried out. Modeling and virtual assembly, using ANSYS Workbench to simulate and analyze the planetary gear transmission. Through the direct integration method of transient dynamics, the equivalent stress, equivalent strain, and equivalent deformation of the planetary gear tooth meshing are obtained, which can provide reference for the future planetary gear transmission design and simulation analysis.
