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Aiming at the problems of long computation time, error-prone results, and difficulty in verification associated with the traditional determinant feedback loop calculation method in system dynamics, a rapid calculation method for system dynamics feedback loops was proposed.This method utilizes the Loops function of Vensim software, the feedback loop set of the system was generated by taking each level bit variable as the starting point, followed by the removal of duplicate feedback loops to obtain a set of all non-repetitive feedback loops in the system. Taking the "Base+Farmers" supply chain complex system of Mingxin Farm in Pingxiang as an example, 11 strongly simplified flow rate basic in-tree models that have been constructed, and both the determinant calculation method and this new method were used to compute all feedback loops in the system.The research showed that both methods yielded the same results, but the fast calculation method of the feedback loop significantly reduced the calculation time and improved the calculation accuracy.Based on this, the system structure can be deeply analyzed to put forward corresponding management countermeasures. [ABSTRACT FROM AUTHOR]

Qualitative analysis of A. senticosus plants in Pingliang was conducted using trait identification and microscopic identification methods, and the content of active ingredients in the leaves of A. senticosus in Pingliang was determined using high-performance liquid chromatography. Trait identification showed that the leaves of A. senticosus in Pingliang were mostly elliptic obovate or oblong, the base was broadly wedged, the edge was heavily serrated, and the leaves had special aroma. Microscopic identification showed that the powder of A. senticosus leaves in Pingliang contained many amorphous pores, threaded conduits, calcium oxalate clusters, fibers and so on. The regression equations of eleutheroside B and eleutheroside E had a good linear relationship, and the RSD of precision, stability and repeatability tests were all less than 5.00%. Among the three extraction methods, microwave ultrasonic-assisted extraction had the highest content of active components, the content of eleutheroside B and eleutheroside E was 0.085% and 0.358%, respectively; microwave extraction method followed, with contents of 0.075% and 0.328%, respectively; the ultrasonic-assisted extraction method had the lowest content, which was 0.054% and 0.222%, respectively. [ABSTRACT FROM AUTHOR]

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Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Advances in Water Science / Shuikexue Jinzhan is the property of Editorial Board of Advances in Water Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to coordinate the relationship between social and economic development and ecology, a water allocation model for Hekoucun Reservoir based on gradual upgrading guarantee for ecological flows was proposed. The results show that four levels for ecological flows (I-IV) are 2.84, 3.98, 5.35 and 7.36 m3/s respectively by basic flow ration and Tennant methods, which are used in the water allocation model as the ecological objective function; in the year of 2030 of long-term planning, the guarantee rates of domestic and industrial and agricultural users are 95.0% and 66.7% respectively. The guarantee rate of river ecology decreases from 71.7% of LevelⅠto 38.3% of Level Ⅳ. Along with the rapid development of society and economy and the growth of population, it will be difficult to coordinate the contradiction among different water users relying only on the inflow of the reservoir. The in-stream ecological water will be squeezed for off-stream water users. In the long run, the river ecosystem will be degraded and destructed. [ABSTRACT FROM AUTHOR]