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| 1 | Effects of landuse change on surface runoff and sediment yield at different watershed scales on the Loess Plateau显示文摘Erosion and sediment yield from large and small watersheds exhibit different laws. Variations in surface runoff and sediment yield because of landuse change in four watersheds of different scales from 1 km2 to 73 km2 were analyzed. Due to reforestation and farmland terracing, surface runoff and sediment yield reduced by 20-100% and 10-100% respectively. Reductions in surface runoff were differed significantly under different precipitation regimes. For the large watershed (73 km2) landuse change had similar effects on surface runoff regardless of changing of precipitation. For the small watershed (1 km2) landuse change had fewer effects on surface runoff under high precipitation. The relative changes of sediment yield in the four watersheds under reforestation and farmland terracing decreased as precipitation increased from 350 mm to 650 mm, then increased as precipitation increased from 650 mm to 870 mm. Where initial forest coverage rate was below 45%, sediment yield decreased dramatically as forest coverage rate increased. Watershed management with aiming at reducing both surface runoff and sediment yield should be conducted both on sloping surfaces and in channels in large watersheds. | ZHANG Xiaoming CAO Wenhong GUO Qingchao WU Sihong | 2010 | International Journal of Sediment Research2010，25，3： | 20 |
| 2 | Regularity of sediment transport and sedimentation during floods in the lower Yellow River,China显示文摘The flood season is the main period of flow,sediment transport,and sedimentation in the lower Yellow River(LYR).Within the flood season,most of the flow,sediment transport,and sedimentation occurs during flood events.Because of the importance of floods in forming riverbeds in the LYR,the regularity of sediment transport and sedimentation during floods in the LYR was studied.Measured daily discharge and sediment transport rate data for the LYR from 1960 to 2006 were used.A total of 299 floods were selected;these floods had a complete evolution of the flood process from the Xiaolangdi to the Lijin hydrological stations.For five hydrological stations(Xiaolangdi,Huayuankou,Gaocun,Aishan,and Lijin),a correlation was first established for floods of different magnitudes between the average sediment transport rate at a given station and the average sediment concentration at the closest upstream station.The results showed that the sediment transport rate at the downstream station was strongly correlated with the inflow(upstream station)sediment concentration during a flood event.A relation then was established between sedimentation in the LYR and the average sediment concentration at the Xiaolangdi station during a flood event.From this relation,the critical sediment concentrations were obtained for absolute erosion,sedimentation equilibrium,and absolute deposition during floods of different magnitudes in the LYR.The results of the current study contribute to a better understanding of the mechanisms of sediment transport and the regularity of sedimentation in the LYR during floods,and provide technical support to guide the joint operation of reservoirs and the regulation of the LYR. | Qingchao Guo Zhao Zheng Liemin Huang Anjun Deng | 2020 | International Journal of Sediment Research2020，35，1： | 6 |
| 3 | Modeling sediment transport in the lower Yellow River and dynamic equilibrium threshold value显示文摘A major problem in the lower Yellow River is the insufficient incoming water and excessive sediment supply, which results in serious deposition, continuous rise of the river bed, and austere flood control situation. To understand the sediment transport regularity of the lower Yellow River and determine the relationship between sedimentation, incoming water and sediment, and zone water diversion, a mathematical model of the sediment suitable for the characteristics of the lower Yellow River has been developed. This model is first rated and verified by large quantity of observed data, and it is then used to analyze silting reduction for the lower Yellow River by Xiaolangdi Reservoir’s operation, the relationship between zone water diversion and channel sedimentation, and critical equilibrium of sedimentation in the lower Yellow River. The threshold values of equilibrium of sedimentation in the lower Yellow River are estimated and they suggest that deposition in the lower Yellow River can be effectively reduced by the operation of regulating flow and sediment from Xiaolangdi Reservoir, water-soil conservation, and controlling water diversion along the lower Yellow River. | HU Chunhong GUO Qingchao | 2004 | Science China(Technological Sciences)2004，47，z1： | 6 |
| 4 | Phytochemical Analysis of Ziziphus jujuba Leaves in Six Cultivars at the Whole Life Stage by High Performance Liquid Chromatography显示文摘 | CUI Xueqin MA Zhongxiao BAI Lu WU Yong GUO Sen LIU Qingchao ZHANG Li HO Chi-Tang BAI Naisheng | 2017 | Chemical Research in Chinese Universities2017，33，5： | 2 |
| 5 | Estimating coefficients in one-dimensional depth-averaged sediment transport model 显示文摘 | Guo Qingchao Jin Yee-Chung | 2001 | Canadian Journal of Civil Engineering CSCE2001，28，3： | 1 |
| 6 | Nine-Step Total Synthesis and Biological Evaluation of Rhizonin A显示文摘of main observation and conclusion We have achieved the total synthesis of an architecturally and biologically intriguing cyclic polypeptide,rhizonin A(1);in an exceptionally concise and convergent fashion.The strategic route entails 9 longest linear steps to elaborate commercially available materials into the natural product with an overall yield of 9.7%.The brevity of sequence and high overall yield was fueled by the judicious selection of chemical tactics.Rhizonin A(1)showed weak inhibitory effects on the cell viability of HCT116 colorectal cancer cells and this activity was dependent on hypoxia-inducible factors. | Qingchao Liu Langlang Liu Ranjala Ratnayake Hendrik Luesch Yian Guo Tao Ye | 2020 | Chinese Journal of Chemistry2020，38，11： | 1 |
| 7 | Flow movement and sediment transport in compound channels 显示文摘 | Hu Chunghong Ji Zuwen Guo Qingchao | 2010 | Journal of Hydraulic Research2010，48，1： | 1 |
| 8 | Estimating coefficients in one-dimensional depth-averaged sediment transport model显示文摘 | Jin Yee-Chung | 2001 | Canadian Journal of Civil Engineering CSCE2001，28，6： | 1 |
| 9 | Non-equilibrium concentration profile formulas of suspended sediment and their preliminary applications显示文摘The vertical concentration profiles in non-equilibrium sediment transport processes generally deviate from the equilibrium concentration distribution of suspended sediment. The non-equilibrium concentration profile formulas currently available are those of Han and Brown, respectively. However, the complexity of these formulas limits their use in practical calculations. To improve the usefulness of these formulas, the unknown parameters in Han’s formula are reduced from three to two, and the three different forms of Brown’s formula are transformed into one. These formulas then are proved to be essentially the same to some extent, and only different in the expression form of the exponent. Han’s formula then is improved, based on which the theoretical calculation methods and distribution characteristics of non-equilibrium profiles are presented. Han’s and Brown’s formulas are verified qualitatively and quantitatively. Finally, these formulas are applied in the investigation of the characteristics of certain physical quantities, such as the recovery factor of sediment concentration, near-bottom sediment flux, and the non-equilibrium P eclet number in the non-equilibrium sediment transport process. These results clearly reveal that the magnitude of these physical quantities decreases in the erosion process and increases in the deposition process. The results also show that the formulas are largely applicable for the non-equilibrium sediment transport conditions. | Zipu Ma Qingchao Guo Jianzhao Guan Maohua Le | 2022 | International Journal of Sediment Research2022，37，4： | 0 |
| 10 | Quantitative Analysis and Chemical Fingerprint Similarity for Quality Control of the Seeds of Paeonia suffruticosa Andr. by HPLC显示文摘 | TIAN Xiao YANG Meiqi GUO Sen LIU Qingchao ZHANG Li HO Chi-Tang BAI Naisheng | 2017 | Chemical Research in Chinese Universities2017，33，4： | 0 |
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