Search

Your search keyword '"Cheng, Xiangju"' showing total 122 results
Start Over Author "Cheng, Xiangju"
122 results on '"Cheng, Xiangju"'

16. Analysis of the Rainfall Pattern and Rainfall Utilization Efficiency during the Growth Period of Paddy Rice.

Author

Chen, Mengting, Shen, Yingying, Wang, Haili, Cheng, Xiangju, and Luo, Yufeng

Subjects
PADDY fields, RAINFALL probabilities, RAINFALL, WATER shortages
Abstract

Rainfall is one of the most important water sources for rice production in China. However, its temporal and spatial variability is leading to water shortages. The present study collected a long series of historical rainfall data from research sites during the rice growth period to analyze the characteristics of rainfall distribution and the correlation with rainfall utilization efficiency, aiming to investigate its impact on rice irrigation practices. It is found that the rainfall distribution varied greatly between the different locations and growth periods. The average rainfall of the whole growth period ranges from 135.5 mm to 694.5 mm. The rainfall curve exhibits a typical unimodal pattern with variations in the intensity, duration, and timing of peak precipitation across different growth periods. During the rice growth period, the cases in southern China are more prone to waterlogging for a high probability of continuous rainfall, and the cases in northern China are more prone to drought. The rainfall utilization efficiency of all cases exhibits a significant inter-year fluctuation range, negatively influenced by the rainfall amount and rainfall inhomogeneity. The efficiency in utilizing precipitation is diminished with greater and more uneven rainfall experienced during the growth period. These findings can provide a decision-making basis for optimizing rice irrigation strategies and enhancing rainfall utilization efficiency in diverse regions across China. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

21. Impact analysis of hydraulic loading rate and antibiotics on hybrid constructed wetland systems: Insight into the response to decontamination performance and environmental-associated microbiota

Author

Baoshan, Shi, primary, Cheng, Xiangju, additional, Zhu, Dantong, additional, Jiang, Shenqiong, additional, Chen, Hongzhan, additional, Zhou, Zhihong, additional, Xie, Jun, additional, Jiang, Yuheng, additional, Liu, Chunsheng, additional, and Guo, Heyi, additional

Published
2023
Full Text
View/download PDF

26. Effect of water temperature on internal nitrogen release from sediments in the Pearl River Delta region, China

Author

Zhu, Dantong, Cheng, Xiangju, Sample, David J., Qiao, Qingsong, Liu, Zhaowei, Zhu, Dantong, Cheng, Xiangju, Sample, David J., Qiao, Qingsong, and Liu, Zhaowei

Abstract

Nitrogen (N) has received attention as an indicator of water quality and pollution. However, there is still a lack of systematic research on its influence of temperature. An experiment was conducted with five tanks containing sediments from the Pearl River Delta region of China and distilled water to assess the release of N from sediments under controlled conditions; temperatures from 10 to 30 degrees C were assessed. Results show that the effect of temperature on N in the water column and sediment is nonlinear. NO3-N was affected at temperatures between 20 and 25 degrees C in shallow sediments (1-3 cm below the sediment-water interface) with rapid increase concentration, while NH4-N concentration in water column was decreased significantly with increased temperature between 10 and 15 degrees C. NO3-N was dominant at temperatures from 25 to 30 degrees C. However, the presence of NH4-N in a water body can inhibit its release, thus the relationship between the diffusive flux with temperature is not linear. The relationship between N diffusive flux at the sediment-water interface was described by Polynomial2D and Lorentz2D models.

Published
2023

36. Impact of microecological agents on water environment restoration and microbial community structures of trench system in a Baiyangdian wetland ecosystem

Author

Zhijun Liu, Cheng Xiangju, Yang Liu, Jun Xie, Chaojiong Sang, Guangjun Wang, Zhang Junwang, and Zhifei Li

Subjects
geography, geography.geographical_feature_category, biology, Bacteria, Nitrogen, Microorganism, Microbiota, Sediment, Wetland, Phosphorus, General Medicine, biology.organism_classification, Applied Microbiology and Biotechnology, chemistry.chemical_compound, Microbial population biology, chemistry, Rhodoferax, Environmental chemistry, Calcium peroxide, Wetlands, Water environment, Environmental science, Water quality, Ecosystem, Biotechnology
Abstract

Aims To evaluate the effects of periodic application of effective microorganism (EM) bacteria and calcium peroxide on water environment restoration of a trench wetland ecosystem and its impact on microbiota in water and sediment. Methods and Results The EM bacteria and calcium peroxide were alternately sprayed into the trench water, and changes in the physicochemical indices of water and sediment, and in microbiota structure were subsequently investigated. Alternately spraying of calcium peroxide and EM bacteria improved the water quality, especially in terms of the dissolved oxygen and transparency of water body, and could further reduce the levels of total nitrogen, total phosphorus and ammonia nitrogen. At the same time, the microbiota structure of the water body was significantly changed by spraying with calcium peroxide and EM bacteria, and the relative abundances of Pseudanabaena, Legionellaceae, Planktothrix, Planctomyces, Phenylobacterium, Rhodobacter, Rhodoferax and Aquirestis were significantly increased. However, there was no significant effect on the physicochemical indexes and microbiota composition of the sediment. Conclusions The water quality of the Baiyangdian trench could be significantly restored by regular sprinkling of calcium peroxide and EM bacteria. Significance and Impact of Study The results provide an effective technical method for the restoration of trench wetland water.

Published
2021

49. Progress in Numerical Simulation of High Entrained Air-Water Two-Phase Flow

Author

Chen Xuewei and Cheng Xiangju

Subjects
Physics::Fluid Dynamics, Flow (mathematics), Computer simulation, Computer science, Turbulence, Multiphase flow, Volume of fluid method, Particle-laden flows, Mechanics, Two-phase flow, Stratified flow, Physics::Atmospheric and Oceanic Physics, Simulation
Abstract

The progress of numerical simulation for high entrained gas-liquid two phase flow were summarized and analyzed. The results show that the Euler-Euler method is the most suitable for the air-water two-phase flow. The advantages and disadvantages of three multiphase flow models (VOF, Mixture and Eulerian model) are analyzed and the results show that the Eulerian model is most popular and accurate for simulation the strong turbulent air-water two-phase flow, especially needing to consider the conversion of continuous and discrete phase. The coupled Eulerian model and mixture turbulence model is the best choice for simulation the flow field on the strong air entrained flow in hydraulic engineering.

Published
2012

Catalog

Books, media, physical & digital resources
See catalog results