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| 1 | Formation and Movement of Groundwater in the Thick Loess-Palaeosol Sequences of the Chinese Loess Plateau显示文摘Permeability and water-bearing space are important hydrological characteristics of the loess strata. In this study a systematic experiment was conducted to measure the magnetic susceptibility, grain size, porosity, and infiltration rate of the loess and palaeosol layers on a loess tableland of the central Chinese Loess Plateau, in order to investigate the differences in hydrological conditions between the loess and palaeosol layers. The magnetic susceptibility of the loess layer was lower than that of the palaeosol layer, but the average quasi-steady infiltration rate was about 0.31 mm min^(-1) higher, the coarse silt and very fine sand contents were about7.1% greater, and the porosity was about 5.7% higher. These differences were mainly due to pedogenesis, which was affected by the Quaternary climate. The pedogenesis differences between the loess and palaeosol layers resulted in hydrological property differences in terms of permeability and water-bearing space. The loess layer had a higher permeability and more water-bearing space than the palaeosol layer, which meant that the loess layer is more likely to form aquifers and the palaeosol layer is more prone to form aquitards.The groundwater in the loess strata had a multilayered characteristic, which depended on the relative impermeability of palaeosol layer and the alternate deposition of loess-palaeosol layers. The hydrological characteristics of the loess strata demonstrated that the Quaternary climate had an important control function on the formation and movement of groundwater. This knowledge provides a reliable theoretical basis for water resource development and utilization on the Chinese Loess Plateau, and this study extends the application of Quaternary climate change theory to hydrological systems in loess deposits. | MA Yandong ZHAO Jingbo LIU Rui ZHOU Qi YIN Leipeng | 2018 | Pedosphere2018，28，6： | 2 |
| 2 | Engineering the morphology and electronic structure of atomic cobalt-nitrogen-carbon catalyst with highly accessible active sites for enhanced oxygen reduction显示文摘The stabilization of non-precious metals as isolated active sites with high loading density over nitrogendoped carbon materials is essential for realizing the industrial application of single atom catalysts.However,achieving high loading of single cobalt active sites with greatly enhanced oxygen reduction reaction(ORR)activity and stability remains challenging.Here,an efficient approach was described to create a single atom cobalt electrocatalyst(Co SAs/NC)which possesses enhanced mesoporosity and specific surface area that greatly favor the mass transportation and exposure of accessible active sites.The electronic structure of the catalyst by the strong metal-support interaction has been elucidated through experimental characterizations and theoretical calculations.Due to dramatically enhanced mass transport and electron transfer endowed by morphology and electronic structure engineering,Co SAs/NC exhibits remarkable ORR performance with excellent activity(onset and half-wave potentials of 1.04 V(RHE)and 0.90 V(RHE),Tafel slope of 69.8 mV dec^(-1)and J_(k) of 18.8 mA cm^(-2)at 0.85 V)and stability(7 mV activity decay after 10,000 cycles).In additio n,the catalyst demonstrates great promise as an alternative to traditional Pt/C catalyst in zinc-air batteries while maintaining high performance in terms of high specific capacity of(796.1 mAh/g_(Zn)),power density(175.4 mW/cm^(2)),and long-term cycling stability(140 h).This study presents a facile approach to design SACs with highly accessible active sites for electrochemical transformations. | Zhijun Li Leipeng Leng Siqi Ji Mingyang Zhang Hongxue Liu Jincheng Gao Jiangwei Zhang J.Hugh Horton Qian Xu Junfa Zhu | 2022 | Journal of Energy Chemistry2022，31，10： | 1 |
| 3 | Analysis of the Mechanisms Underpinning Rainstorm-Induced Landslides显示文摘The present study considers the damage mechanisms and the rainfall infiltration process responsible for landslide phenomena which originate from accumulation slopes.Accordingly,a physical test model is developed for different slopes and different rainfall conditions.Moreover,a three-dimensional laser scanner and a camera are used to monitor the slope erosion and the landslide dynamic evolution.Using this approach,the time variation curves of volumetric water content,pore water pressure,soil pressure,slope deformation,and damage are determined.The results show that under similar conditions,similar trends of the pore water pressure are achieved for different slopes and rainfall intensities. | Shaojie Feng Leipeng Liu Chen Gao Hang Hu | 2023 | Fluid Dynamics & Materials Processing2023，19，5： | 0 |
| 4 | Surface protection method for the magnetic core using covalent organic framework shells and its application in As(Ⅲ)depth removal from acid wastewater显示文摘Fe_(3)O_(4)-based materials are widely used for magnetic separation from wastewater.However,they often suffer from Fe-leaching behavior under acidic conditions,decreasing their ac-tivity and limiting sustainable practical applications.In this study,covalent organic frame-works(COFs)were used as the shell to protect the Fe_(3)O_(4) core,and the Fe_(3)O_(4)@COF core-shell composites were synthesized for As(Ⅲ)removal from acid wastewater.The imine-linked COFs can in situ grow on the surface of the Fe_(3)O_(4) core layer by layer with[COFs/Fe_(3)O_(4)]mol ratio of up to 2∶1.The Fe-leaching behavior was weakened over a wide pH range of 1-13.Moreover,such composites keep their magnetic characteristic,making them favorable for nanomaterial separation.As(Ⅲ)batch adsorption experiments results indicated that,when COFs are used as the shell for the Fe_(3)O_(4) core,a balance between As(Ⅲ)removal efficiencies and the thickness of the COF shell exists.Higher As(Ⅲ)removal efficiencies are obtained when the[COFs/Fe_(3)O_(4)]mol ratios were<1.5∶1,but thicker COF shells were not beneficial for As(Ⅲ)removal.Such composites also exhibited better As(Ⅲ)removal performances in the pH range of 1-7.Over a wide pH range,the zeta potential of Fe_(3)O_(4)@COF core-shell compos-ites becomes more positive,which benefits the capture of negative arsenic ions.In addition,thinner surface COFs were favorable for mass transfer and facilitating the reaction of Fe and As elements.Our study highlights the promise of using COFs in nanomaterial surface protection and achieving As(Ⅲ)depth removal under acidic conditions. | Wenjun Huang Haomiao Xu Xiaoshuang Liu Longlong Wang Shutang Li Leipeng Ji Zan Qu Naiqiang Yan | 2022 | Journal of Environmental Sciences2022，34，5： | 0 |
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